National Taiwan Ocean University Research Hubhttps://scholars.ntou.edu.twThe DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Sat, 09 Nov 2024 23:04:09 GMT2024-11-09T23:04:09Z50701Enhanced photoluminescence of DCJTB by silver nanohole arrays with ring-shaped silver nanoparticles over hyperbolic metamaterialshttp://scholars.ntou.edu.tw/handle/123456789/25283Title: Enhanced photoluminescence of DCJTB by silver nanohole arrays with ring-shaped silver nanoparticles over hyperbolic metamaterials
Authors: Chen, Sy-Hann; Fang, Jun-Kai; Du, Cheng-Han; Shih, Min-Hsiung; Liang, Hsing-Chih; Chiang, Hai - Pang
Abstract: In this study, a novel approach for fabricating silver nanohole arrays (AgNAs) on silicon/hyperbolic metamaterial (Si/HMM) substrates is described. This approach involves the use of fixed -size plastic nanoparticles combined with reactive -ion etching, followed by decoration with silver nanoparticles (AgNPs) around the edges of the Ag nanoholes. The HMM structure is composed of six pairs of alternating layers of silver and silicon dioxide (Ag/SiO2). Herein, the interaction of the localized surface plasmon resonance (LSPR) is investigated by the analysis of photoluminescence (PL) responses of 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl- 9-enyl)-4H-pyran (DCJTB) molecules over the AgNAs on the Si/HMM substrates. Both configurations, i.e., with and without ring -shaped AgNPs, are investigated extensively by a combination of experimental measurements and numerical simulations. The substantially enhanced PL for the proposed substrates can be attributed to increased light absorption, leading to the fine-tuning of surface -enhanced electromagnetic fields. Notably, the PL intensity of DCJTB is significantly enhanced (16.4 times) in comparison with that of the reference substrate. Concurrently, the PL lifetime is reduced by 49.45% (0.91 ns-0.46 ns). These results underscore the transformative potential of these enhanced substrates in reshaping the landscape of sensing platforms. The enhanced PL response coupled with the precisely tunable LSPR effects demonstrates promise for innovative applications in optical and photonic technologies.
Mon, 01 Jan 2024 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/252832024-01-01T00:00:00ZInvestigation of low pulse repetition passively mode-locked Nd:YVO4 lasers via multi-pass periodic trajectories in a confocal cavityhttp://scholars.ntou.edu.tw/handle/123456789/25199Title: Investigation of low pulse repetition passively mode-locked Nd:YVO4 lasers via multi-pass periodic trajectories in a confocal cavity
Authors: Liang, Hsing-Chih; Hsu, Yu-Hsin; Chiang, Hai-Pang
Abstract: We derive the parametric equations for the geometric rays of a periodic orbit inside a confocal cavity. Based on the derived formula, we demonstrate a passively mode -locked solid-state laser with a low pulse repetition rate to obtain a pulse train traveling along zigzag multi -pass trajectories. We achieve a stable mode -locked pulse train with a pulse repetition rate of 18 MHz by designing the cavity to satisfy the dual -M trajectory. Furthermore, by precisely adjusting cavity mirrors under the same experimental setup, we can reach pulse repetition rates of 12 and 9 MHz for the modelocked laser. It is believed that the numerical calculation and the developed experiment can provide a straightforward and convenient way to achieve a low pulse repetition rate for passively mode -locked lasers. (c) 2024 Optica Publishing Group
Mon, 01 Jan 2024 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/251992024-01-01T00:00:00ZEnhanced optical sensing with metal-insulator-metal nanohole arrays integrated with silver nanoparticleshttp://scholars.ntou.edu.tw/handle/123456789/24676Title: Enhanced optical sensing with metal-insulator-metal nanohole arrays integrated with silver nanoparticles
Authors: Chu, Cheng Hung; Lin, Gu Yu; Wu, Pin Chieh; Chou, Wei-Yang; Chen, Sy-Hann; Liang, Hsing-Chih; Chiang, Hai -Pang
Abstract: The field of plasmonic sensing has witnessed rapid advancements in recent years. This work proposes an innovative methodology that employs metal-insulator-metal (MIM) nanohole arrays integrated with ring-shaped silver nanoparticles (AgNPs) to serve as an effective plasmonic refractive index sensor. The hybrid substrates are prepared using a combination of nanosphere lithography (NSL), reactive ion etching, and an enhanced plasmonic site-selective photocatalytic reaction, ensuring large-area fabrication, high throughput, and cost-effectiveness. The resonance peaks observed in the visible-NIR spectra are attributed to the coupling of surface plasmon resonance modes between MIM structures and AgNPs. The resonance wavelength exhibits sensitively to changes in the surrounding medium within the refractive index range of 1 to 1.5, with a remarkable sensitivity of 835 nm/RIU. Our findings reveal the significant potential of this technology for advancing optical sensing applications.
Sun, 01 Jan 2023 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/246762023-01-01T00:00:00ZContinuous wave dual-wavelength Nd:YVO4 laser at 1342 and 1525 nm for generating a 714-nm emissionhttp://scholars.ntou.edu.tw/handle/123456789/22171Title: Continuous wave dual-wavelength Nd:YVO4 laser at 1342 and 1525 nm for generating a 714-nm emission
Authors: Chen, Y. F.; Zheng, Z. X.; Huang, C. Y.; Guo, B. C.; Tsou, C. H.; Liang, H. C.
Abstract: Continuous wave dual-wavelength lasers at 1342 and 1525 nm are developed by using separate Nd:YVO4 and YVO4 crystals to form compactly coupled cavities for fundamental and Raman waves, respectively. The design of the coupled cavity not only reduces the thermal lensing effect in the Nd:YVO4 crystal, but also improves the stimulated Raman scattering (SRS) efficiency in the undoped YVO4 crystal. In addition, the Raman crystal is coated to form a highly reflective mirror to minimize cavity losses. By using a plano-concave cavity with a pump power of 40 W, the output powers of the fundamental and Raman waves are 470 mW and 310 mW, respectively. Changed to a concave cavity, the output powers of fundamental and Raman waves are 220 mW and 510 mW, respectively. Basis on the dual-wavelength operation, the maximum output power at 714 nm can reach 2.0 W via the sum frequency generation. A light source at 714 nm can be used for laser spectroscopy of atomic and ionic radium isotopes. (C) 2022 Optica Publishing Group
Mon, 01 Aug 2022 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/221712022-08-01T00:00:00ZStructured transverse modes governed by maximum entropy principlehttp://scholars.ntou.edu.tw/handle/123456789/22170Title: Structured transverse modes governed by maximum entropy principle
Authors: Tung, J. C.; Ke, H. T.; Liang, H. C.; Huang, K. F.; Chen, Y. F.
Abstract: Based on the birefringent effect of the gain medium, a diode-pumped Nd-doped vanadate laser with nearly hemispherical cavity is exploited to emulate the quantum Green functions of two-dimensional commensurate harmonic oscillators. By matching the theoretical calculations to the far-field patterns of lasing modes, the resonant transverse frequencies can be accurately determined up to extremely high orders. The Shannon entropy is further employed to calculate the spatial entanglement of the quantum Green function as a function the transverse frequency. From the resonant transverse frequencies, all lasing modes are confirmed to be in excellent agreement with the maximum entropy states. This discovery implies that the formation of lasing modes is relevant to the coupling interaction between the pump source and the laser cavity. (C) 2022 Optica Publishing Group
Mon, 01 Aug 2022 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/221702022-08-01T00:00:00ZContinuous-Wave Crystalline Laser at 714 nm via Stimulated Raman Scattering and Sum Frequency Generationhttp://scholars.ntou.edu.tw/handle/123456789/22188Title: Continuous-Wave Crystalline Laser at 714 nm via Stimulated Raman Scattering and Sum Frequency Generation
Authors: Huang, Chien-Yen; Guo, Bo-Cheng; Zheng, Zi-Xuan; Tsou, Chia-Han; Liang, Hsing-Chih; Chen, Yung-Fu
Abstract: A compact high-power continuous-wave (CW) laser at 714 nm is originally developed via intracavity stimulated Raman scattering (SRS) and sum frequency generation (SFG). The fundamental wave at 1342 nm and the first-Stokes Raman wave at 1525 nm are generated by using a Nd:YVO4 and a undoped YVO4 crystals, respectively. Compared to the self-Raman laser, the separation of the gain media for generating the fundamental and Raman waves can effectively reduce the thermal lens effect in the Nd:YVO4 crystal and efficiently enhance the SRS in the undoped YVO4 crystal. Furthermore, the undoped YVO4 crystal is coated to act as a high-reflection mirror for minimizing the cavity losses. At a pump power of 40 W, the output power at 714 nm can reach 1.8 W. The present compact design for CW laser source at 714 nm is believed to be practically useful for laser cooling and trapping of radium.
Mon, 01 Aug 2022 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/221882022-08-01T00:00:00ZCharacterizing propagation-dependent spatial entanglement for structured laser beams generated by an astigmatic mode converterhttp://scholars.ntou.edu.tw/handle/123456789/22069Title: Characterizing propagation-dependent spatial entanglement for structured laser beams generated by an astigmatic mode converter
Authors: Yu, Y. T.; Hsieh, M. X.; Liang, H. C.; Chen, Y. F.
Abstract: The propagation-dependent spatial entanglement for the structured laser beams generated by an arbitrary incident Hermite-Gaussian (HG) mode passing through an astigmatic mode converter (AMC) is theoretically explored. The structured output beams are analytically decomposed into the expansion of HG modes for any given rotation angle of the AMC. Based on the Schmidt decomposition, the propagation-dependent spatial entanglements of the structured output modes are quantified with the von Neumann entropy. To manifest the propagation-dependent entropy, the probability distribution of the expanded HG modes in the structured output beam is quantitatively analyzed. (C) 2022 Optica Publishing Group
Fri, 01 Jul 2022 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/220692022-07-01T00:00:00ZFormation of liquid crystal gratings with crystal/quasicrystal patterns through photoalignmenthttp://scholars.ntou.edu.tw/handle/123456789/21064Title: Formation of liquid crystal gratings with crystal/quasicrystal patterns through photoalignment
Authors: Lin, Hui-Chi; Xu, Zhe-Wei; Li, Ming-Hsien; Hsu, Chi-Shiang; Liang, Hsing Chih
Abstract: In this study, a simple method for generation of liquid crystal (LC) grating with crystal/quasicrystal/kaleidoscopic patterns via photoalignment is proposed. The crystal/quasicrystal/kaleidoscopic patterns are created using multiple-beam interference when the recording beam is divided into multiple beams by passing a multiple-aperture mask and focused by a lens. Two-dimensional (2D) patterns are recorded on LC cells based on the laser-induced adsorption of azo dyes that guide the orientation of the LC molecules. Measurements indicate that the 2D LC gratings with crystal/quasicrystal patterns are electro-optically tunable and possess polarisation-independent diffraction efficiency.
Sat, 12 Feb 2022 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/210642022-02-12T00:00:00ZModeling for Spatial Overlap Effect of End-Pumped Passively Q-Switched Nd:YVO4/Cr4+:YAG Laser and Its Experimental Verificationhttp://scholars.ntou.edu.tw/handle/123456789/21388Title: Modeling for Spatial Overlap Effect of End-Pumped Passively Q-Switched Nd:YVO4/Cr4+:YAG Laser and Its Experimental Verification
Authors: Tu, Yueh-Chi; Hsieh, Min-Xiang; Liang, Hsing-Chih; Yu, Yan-Ting
Abstract: In this work, the spatial effects of the pumping and lasing were considered into the coupled rate equations of passively Q-switched lasers for the condition of no saturation in the gain medium. A transcendental equation of energy utilization was derived, and the solution to the equation was approximated by an analytic model developed in previous work. The reflection factor of output coupler with low reflectivity was modified for more accurate output energy evaluations. Experimentally, an end-pumped Nd:YVO4/Cr4+:YAG laser in a concave-plano cavity with output coupling reflectivity ranging from 10% to 92% was demonstrated, and two different pumping spot sizes of laser diode were adopted for validating the developed spatial model. The experimental results showed good agreements with the theoretical calculations.
Tue, 01 Feb 2022 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/213882022-02-01T00:00:00ZKerr-lens mode-locked Yb:SrLaAlO4 laserhttp://scholars.ntou.edu.tw/handle/123456789/19557Title: Kerr-lens mode-locked Yb:SrLaAlO4 laser
Authors: Lin, Zhang-Lang; Zeng, Huang-Jun; Zhang, Ge; Xue, Wen-Ze; Pan, Zhongben; Lin, Haifeng; Loiko, Pavel; Liang, Hsing-Chih; Petrov, Valentin; Mateos, Xavier; Wang, Li; Chen, Weidong
Abstract: We report on the firstKerr-lens mode-locked laser based on the Yb3+-doped disordered strontium lanthanum aluminate crystal, Yb:SrLaAlO4 (Yb:SALLO), pumped by a high-brightness Yb fiber laser at 976 nm. Nearly Fourier-limited pulses as short as 44 fs were achieved at 1051 nm with an average output power of 277 mW and a pulse repetition rate of similar to 66 MHz via soft-aperture Kerr-lens mode-locking. A higher average output power of 459 mW, corresponding to an optical efficiency of 33.8%, was obtained at the expense of a slightly longer duration (52 fs). (C) 2021 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
Mon, 20 Dec 2021 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/195572021-12-20T00:00:00ZReliable self-healing FBG sensor network for improvement of multipoint strain sensinghttp://scholars.ntou.edu.tw/handle/123456789/17814Title: Reliable self-healing FBG sensor network for improvement of multipoint strain sensing
Authors: Hayle, Stotaw Talbachew; Manie, Yibeltal Chanie; Dehnaw, Amare Mulatie; Hsu, Yuan-Ta; Li, Jyun-Wei; Liang, Hsing-Chin; Peng, Peng-Chun
Abstract: In this paper, we proposed and designed reliable self-healing fiber Bragg grating (FBG) sensor network for improvement of multipoint strain sensing. We use an optical switch (OSW) to reconfigure the sensor network and improve the self-healing function during fault happen in the sensor network. In this work, to prove and validate the detection performance of our proposed Bragg wavelength detection technique even when the number of overlap spectra of FBGs increases, we conduct three experiments and collect three different cases of strain data (namely case 1, case 2, and case 3) by applying different strain steps to FBGs. In case 1 experiment, strain was applied to only FBG1 sensor, while the other four FBGs keeps fixed. In case 2 experiment, strain was applied to FBG1 and FBG2 sensors at the same time and with different strain steps. In case 3 experiment, strain was applied to FBG1, FBG2 and FBG3 sensors at the same time and with different strain steps. As a result, in all cases of the experiment, three situations of spectra were introduced between FBGs like non overlapped, partially overlapped and completely overlapped spectra. To solve this overlap problem, we used deep learning technique to accurately identify the Bragg wavelength of FBGs in the condition of the partially or fully overlapped spectra. Therefore, our proposed FBG sensor system can improve the reliability and detection accuracy of the sensor system even the number of overlaps FBGs spectra increases.
Mon, 15 Nov 2021 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/178142021-11-15T00:00:00ZExploiting Modern Chladni Plates to Analogously Manifest the Point Interactionhttp://scholars.ntou.edu.tw/handle/123456789/19131Title: Exploiting Modern Chladni Plates to Analogously Manifest the Point Interaction
Authors: Tseng, Yu-Chen; Hsu, Yu-Hsin; Lai, Yu-Hsiang; Yu, Yan-Ting; Liang, Hsing-Chih; Huang, Kai-Feng; Chen, Yung-Fu
Abstract: A truncated basis is employed to analyze the influence of the point interaction on the eigenvalues and eigenfunctions in quantum billiards. The point interaction is numerically confirmed to cause the shift in the eigenvalue that leads the original eigenfunctions to be superposed to form the new eigenfunction. The amplitude and nodal-line patterns of the eigenfunctions are found to vary significantly with the coupling strength. It is further verified that the point-driven Chladni plates can be employed to analogously manifest the noticeable dependence of the nodal-line pattern on the coupling strength. More importantly, the dispersion relation between the frequency and the wave number for the flexural wave can be precisely determined in the process of utilizing the point interaction to model the modern Chladni plates.
Mon, 01 Nov 2021 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/191312021-11-01T00:00:00ZQuantum entanglement by a beam splitter analogous to laser mode transformation by a cylindrical lenshttp://scholars.ntou.edu.tw/handle/123456789/18208Title: Quantum entanglement by a beam splitter analogous to laser mode transformation by a cylindrical lens
Authors: Chen, Y. F.; Hsieh, M. X.; Ke, H. T.; Yu, Y. T.; Liang, H. C.; Huang, K. F.
Abstract: Quantum entanglement by a beam splitter (BS) is shown to be analogous to laser mode transformation by an astigmatic mode converter (AMC). Schmidt decomposition is used to characterize the entanglement by an AMC for generating orbital angular momentum and by a BS for creating quantum photon interference. The probability distributions of Schmidt decomposition are calculated to manifest the sameness and difference betweenAMCand BS in generating entanglement. Finally, the theoretical patterns of mode transformations by an AMC are confirmed with experimental results to validate the present analysis. (C) 2021 Optical Society of America.
Fri, 15 Oct 2021 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/182082021-10-15T00:00:00ZSelf-Start Multi-Wavelength Laser Source with Tunable Delay-Line Interferometer and Optical Fiber Reflector for Wireless Communication Systemhttp://scholars.ntou.edu.tw/handle/123456789/19536Title: Self-Start Multi-Wavelength Laser Source with Tunable Delay-Line Interferometer and Optical Fiber Reflector for Wireless Communication System
Authors: Dehnaw, Amare-Mulatie; Shiu, Run-Kai; Chen, Ruei-Bin; Li, Jyun-Wei; Manie, Yibeltal-Chanie; Liang, Hsing-Chih; Peng, Peng-Chun
Abstract: The radio-over-fiber (RoF) technique has gained a lot of interest recently, as the millimeter-wave signals can be generated and delivered in the optical domain with the advantages of low attenuation, high capacity, and being free from electromagnetic noise interference (EMI). In this paper, we propose and experimentally prove a self-start multi-wavelength laser source based on a distributed feedback laser diode (DFB-LD) for the RoF transport system. The self-start multi-wavelength laser source generates stable laser power with less than 0.18 dB power fluctuation and exhibits good stability. In order to estimate the transmission performance, data is externally modulated onto the multi-wavelength by a reflective semiconductor optical amplifier (RSOA) and transmitted through single-mode fiber (SMF). The experimental result proves that the proposed RoF transport system achieves error-free transmission and clear eye diagrams.
Fri, 01 Oct 2021 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/195362021-10-01T00:00:00ZSystematically Investigating the Structural Variety of Crystalline and Kaleidoscopic Vortex Lattices by Using Laser Beam Arrayshttp://scholars.ntou.edu.tw/handle/123456789/17795Title: Systematically Investigating the Structural Variety of Crystalline and Kaleidoscopic Vortex Lattices by Using Laser Beam Arrays
Authors: Chen, Chengshang; Fang, Yuhan; Jang, Chichen; Chen, Wenchi; Lin, Hui-Chi; Liang, Hsingchih
Abstract: We theoretically demonstrate that a family of vortex-lattice structures can be flexibly generated using a multi-beam interference approach. Numerical calculation presents a variety of crystalline and kaleidoscopic patterns. Based on the numerical analysis, we experimentally realized these structure beams by combining an amplitude mask with multiple apertures and a spiral phase plate. The excellent agreement between the experimental and theoretical results not only validates the presented method, but also manifests the structure of vortex lattices.
Wed, 01 Sep 2021 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/177952021-09-01T00:00:00ZCharacterizing the spatial entanglement from laser modes analogous to quantum wave functionshttp://scholars.ntou.edu.tw/handle/123456789/17764Title: Characterizing the spatial entanglement from laser modes analogous to quantum wave functions
Authors: Hsieh, M. X.; Zheng, X. L.; Yu, Y. T.; Liang, H. C.; Huang, K. F.; Chen, Y. F.
Abstract: The Schmidt decomposition is exploited to study the spatial entanglement of laser transverse modes analogous to quantum Lissajous states. Based on the inverse Fourier transform, the stationary Lissajous state can be analytically derived as a coherent superposition of degenerate Hermite-Gaussian eigenmodes. With the derived stationary state, the Schmidt modes and the participation number N can be employed to evaluate the spatial localization and the quantum entanglement. The larger the participation number, the more localized is the stationary coherent state on the Lissajous figure. Moreover, the larger the participation number, the higher is the spatial entanglement. (C) 2021 Optical Society of America
Sun, 01 Aug 2021 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/177642021-08-01T00:00:00ZPowerful Q-switched Raman laser at 589 nm with a repetition rate between 200 and 500 kHzhttp://scholars.ntou.edu.tw/handle/123456789/17367Title: Powerful Q-switched Raman laser at 589 nm with a repetition rate between 200 and 500 kHz
Authors: Hsiao, J. Q.; Huang, Yu Jung; Lee, C. C.; Yu, Y. T.; Tsou, C. H.; Liang, H. C.; Chen, Y. F.
Abstract: We demonstrate a highly powerful acousto-optically Q-switched Nd:YVO4 yellow laser at 589 nm by using a N-p-cut KGW crystal and a phase-matching lithium triborate crystal to performance the intracavity stimulated Raman scattering and second-harmonic generation, respectively. We experimentally verify that the design of the separate cavity is superior to the conventional design of the shared cavity. By using the separate cavity, the optical-to-optical efficiency can be generally higher than 32% for the repetition rate within 200-500 kHz. The maximum output power at 589 nm can be up to 15.1 W at an incident pump power of 40 W and a repetition rate of 400 kHz. (C) 2021 Optical Society of America
Sat, 01 May 2021 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/173672021-05-01T00:00:00ZPedagogically fast model to evaluate and optimize passively Q-switched Nd-doped solid-state lasershttp://scholars.ntou.edu.tw/handle/123456789/17314Title: Pedagogically fast model to evaluate and optimize passively Q-switched Nd-doped solid-state lasers
Authors: Chen, Y. F.; Hsieh, M. X.; Tu, Y. C.; Lee, C. C.; Yu, Y. T.; Tsou, C. H.; Liang, H. C.
Abstract: The coupled rate equations with the spatial overlap effect for four-level passively Q-switched lasers are fully considered. A transcendental equation is derived for the residual fraction of the inversion density after the finish of the Q-switched pulse. Comprehensive calculations for the transcendental equation were executed to attain an analytical function for precisely fitting the residual fraction of the inversion density. With the fitting function, a pedagogical model with the correction for high output coupling is developed to straightforwardly analyze the output pulse energy and peak power. Detailed experiments are carried out to validate the model. (C) 2021 Optical Society of America
Thu, 01 Apr 2021 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/173142021-04-01T00:00:00ZHighly efficient solid-state Raman yellow-orange lasers created by enhancing the cavity reflectivityhttp://scholars.ntou.edu.tw/handle/123456789/17170Title: Highly efficient solid-state Raman yellow-orange lasers created by enhancing the cavity reflectivity
Authors: Chen, Y. F.; Li, D.; Lee, Y. M.; Lee, C. C.; Huang, H. Y.; Tsou, C. H.; Liang, H. C.
Abstract: A new, to the best of our knowledge, output coupler (OC) with enhancement of the cavity reflectivity is proposed to remarkably elevate the output powers and efficiencies of diode-pumped Nd:GdVO4/KGW Raman yellow-orange lasers. The cavity reflectivity is effectively increased by using the double-sided dichroic coating on the OC. In comparison with the conventional single-sided coating, the conversion efficiency can be boosted from 15% to 26.3% in the experiment of a yellow laser at 578.8 nm, and the maximum output power can be increased from 5.7 to 10.5 W in the quasi-continuous-wave mode with 50% duty cycle and frequency of 500 Hz. Furthermore, in the operation of an orange laser at 588 nm, the maximum output power can be improved from 5.6 to 7.0 W by replacing the conventional OC with the new one. (C) 2021 Optical Society of America
Mon, 15 Feb 2021 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/171702021-02-15T00:00:00ZTunable pretilt angle based on gelator-doped planar liquid crystal cellshttp://scholars.ntou.edu.tw/handle/123456789/17132Title: Tunable pretilt angle based on gelator-doped planar liquid crystal cells
Authors: Lin, Hui-Chi; Ke, Li-Yun; Liang, Hsing Chih; Kuo, Wen-Kai
Abstract: This study demonstrates a simple approach for controlling the pretilt angles of liquid crystals (LCs) using gelator-doped cells fabricated with homogeneously aligned substrates. The competition between the gelator-induced spontaneous vertical alignment and planar alignment layer coated on the substrates results in various pretilt angles of LCs. The LC pretilt angle can thus be controlled from a homeotropic to planar state by adjusting the anchoring energy of the planar alignment layer and gelator concentration used for doping. A no-bias pi cell with multistable property is demonstrated by utilizing the proposed method.
Mon, 25 Jan 2021 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/171322021-01-25T00:00:00ZInvestigation of anisotropic thermal lens effect in a dual-polarized Nd:YLF laserhttp://scholars.ntou.edu.tw/handle/123456789/17108Title: Investigation of anisotropic thermal lens effect in a dual-polarized Nd:YLF laser
Authors: Chen, Chi-Wen; Fang, Yu-Han; Cho, Chun-Yu; Liang, Hsing-Chih
Abstract: The anisotropic thermal lens effect of a dual-polarization Nd:YLF laser is experimentally investigated by measuring the transverse beat frequency between TEM0,0 and TEM1,0 modes in the self-pulsing operation, and focal lengths of thermal lensing for both polarizations can be accurately determined. The focal length of the thermal lens for pi polarization was observed to be negative and varies from -1.1 to -0.5 m for the absorbed pump power increasing from 1.7 to 3.8 W. For sigma polarization, the focal length of the thermal lens was determined to be positive and varies from 1.2 to 0.9 m for the absorbed pump power increasing from 8.4 to 10.9 W. The sensitivity factors of the thermal lens for both polarizations were evaluated to be M-pi = -0.54 m(-1) /W and M-sigma = 0.1 m(-1)/W, respectively. (C) 2020 Optical Society of America
Fri, 01 Jan 2021 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/171082021-01-01T00:00:00ZPropagation-dependent evolution of interfering multiple beams and kaleidoscopic vortex latticeshttp://scholars.ntou.edu.tw/handle/123456789/17302Title: Propagation-dependent evolution of interfering multiple beams and kaleidoscopic vortex lattices
Authors: Chen, Y. F.; Tu, Y. C.; Li, S. C.; Hsieh, M. X.; Yu, Y. T.; Liang, H. C.; Huang, K. F.
Abstract: In this Letter, we experimentally explore the propagation-dependent evolution of generating the pseudo-nondiffracting quasi-crystalline (crystalline) beams based on the multibeam interference. We originally derived an analytical formula to exactly manifest the propagation evolution of interfering multiple beams. With the analytical formula, the formation of quasi-crystalline structures in the focal plane can be explicitly verified. Furthermore, the distance of the effective propagation-invariant region can be verified in terms of experimental parameters. More importantly, we employed the developed formula to confirm the formation of kaleidoscopic vortex lattices by means of numerically computing the propagation-dependent phase singularities. (C) 2020 Optical Society of America
Fri, 01 Jan 2021 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/173022021-01-01T00:00:00ZEfficient solid-state Raman yellow laser at 579.5 nmhttp://scholars.ntou.edu.tw/handle/123456789/2541Title: Efficient solid-state Raman yellow laser at 579.5 nm
Authors: Chen, Y. F.; Chen, C. M.; Lee, C. C.; Huang, H. Y.; Li, D.; Hsiao, J. Q.; Tsou, C. H.; Hsing-Chin Liang
Thu, 01 Oct 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/25412020-10-01T00:00:00ZHigh-power diode-pumped Nd:GdVO4/KGW Raman laser at 578 nmhttp://scholars.ntou.edu.tw/handle/123456789/2543Title: High-power diode-pumped Nd:GdVO4/KGW Raman laser at 578 nm
Authors: Chen, Y. F.; Huang, H. Y.; Lee, C. C.; Hsiao, J. Q.; Tsou, C. H.; Hsing-Chin Liang
Thu, 01 Oct 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/25432020-10-01T00:00:00ZHigh-power diode-pumped Nd:GdVO4/KGW Raman laser at 578 nmhttp://scholars.ntou.edu.tw/handle/123456789/22389Title: High-power diode-pumped Nd:GdVO4/KGW Raman laser at 578 nm
Authors: Chen, Y. F.; Huang, H. Y.; Lee, C. C.; Hsiao, J. Q.; Tsou, C. H.; Liang, H. C.
Abstract: A diode-pumped neodymium-doped gadolinium vanadate (Nd:GdVO4) laser is developed as a compact efficient yellow light at 578 nm by means of intracavity stimulated Raman scattering (SRS) in a potassium gadolinium tungstate (KGW) crystal and the second-harmonic generation in a lithium triborate crystal. The SRS process with a shift of 768 cm(-1) is achieved by setting the polarization of the fundamental wave along the N-g axis of the KGW crystal. The self-Raman effect arising from the Nd:GdVO4 crystal is systematically explored by employing two kinds of coating specification for the output coupler. With a specific coating on the output coupler to suppress the self-Ram an effect, the maximum output power at 578 nm can reach 3.1 W at a pump power of 32 W. Moreover, two different lengths for the Nd:GdVO4 crystal are individually used to verify the influence of the self-Raman effect on the lasing efficiency. (C) 2020 Optical Society of America
Thu, 01 Oct 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/223892020-10-01T00:00:00ZEfficient solid-state Raman yellow laser at 579.5 nmhttp://scholars.ntou.edu.tw/handle/123456789/22388Title: Efficient solid-state Raman yellow laser at 579.5 nm
Authors: Chen, Y. F.; Chen, C. M.; Lee, C. C.; Huang, H. Y.; Li, D.; Hsiao, J. Q.; Tsou, C. H.; Liang, H. C.
Abstract: A highly efficient diode-pumped Nd:YVO4/KGW Raman yellow laser is developed to produce a 6.8 W yellow light at 579.5 nm accompanied by a 3.2 W Stokes wave at 1159 nm under an incident pump power of 30 W. The intracavity stimulated Raman scattering with the shift of 768 cm(-1) is generated by setting the polarization of the fundamental wave along the N-g direction of an N-p-cut KGW crystal. The Nd:YVO4 gain medium is coated as a cavity mirror to reduce the cavity losses for the fundamental wave. More importantly, the KGW crystal is specially coated to prevent the Stokes wave from propagating through the gain medium to minimize the cavity losses for the Stokes wave. (C) 2020 Optical Society of America
Thu, 01 Oct 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/223882020-10-01T00:00:00ZHigh-power structured laser modes: manifestation of quantum Green's functionhttp://scholars.ntou.edu.tw/handle/123456789/22378Title: High-power structured laser modes: manifestation of quantum Green's function
Authors: Chen, Y. F.; Tseng, Y. C.; Ke, H. T.; Hsieh, M. X.; Tung, J. C.; Hsieh, Y. H.; Liang, H. C.; Huang, K. F.
Abstract: The distributions of resonant frequencies in an astigmatic cavity are theoretically confirmed to be analogously equivalent to the quantum energy structures of two-dimensional commensurate harmonic oscillators. In the first part [Opt. Lett. 45, 4096 (2020)] of this two-part series study, the lasing modes were verified to reveal a variety of vortex array structures. Here, in the second part of this two-part series study, the lasing modes are confirmed to agree very well with the quantum Green's functions that correspond to a bundle of Lissajous figures in the high-order regime. (C) 2020 Optical Society of America
Sat, 15 Aug 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/223782020-08-15T00:00:00ZHigh-power structured laser modes: manifestation of quantum Green's functionhttp://scholars.ntou.edu.tw/handle/123456789/2551Title: High-power structured laser modes: manifestation of quantum Green's function
Authors: Chen, Y. F.; Tseng, Y. C.; Ke, H. T.; Hsieh, M. X.; Tung, J. C.; Hsieh, Y. H.; Hsing-Chin Liang; Huang, K. F.
Sat, 01 Aug 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/25512020-08-01T00:00:00ZExploiting a monolithic passively Q-switched Nd:YAG laser to mimic a single neuron cell under periodic stimulationhttp://scholars.ntou.edu.tw/handle/123456789/22377Title: Exploiting a monolithic passively Q-switched Nd:YAG laser to mimic a single neuron cell under periodic stimulation
Authors: Chen, Y. F.; Lee, C. C.; Hsiao, J. Q.; Huang, H. Y.; Tsou, C. H.; Liang, H. C.; Huang, K. F.
Abstract: A monolithic passively Q-switched Nd:YAG laser under periodic pulse pumping is originally exploited to emulate the response of a single neuron cell stimulated by periodic pulse inputs. Experimental results reveal that the output characteristics of the monolithic passively Q-switched laser can analogously manifest not only the firing patterns but also the frequency-locked plateaus of the single neuron cell. Moreover, the sine circle map is innovatively used to generate the output pulse sequences that can exactly correspond to experimental firing patterns. The present exploration indicates that a monolithic passively Q-switched solid-state laser is highly feasible to be developed as a compact artificial neuron cell. (C) 2020 Optical Society of America
Wed, 15 Jul 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/223772020-07-15T00:00:00ZHigh-power structured laser modes: direct generation of a vortex arrayhttp://scholars.ntou.edu.tw/handle/123456789/22376Title: High-power structured laser modes: direct generation of a vortex array
Authors: Chen, Y. F.; Ke, H. T.; Tseng, Y. C.; Hsieh, M. X.; Tung, J. C.; Hsieh, Y. H.; Liang, H. C.; Huang, K. F.
Abstract: The frequency degeneracy induced by the astigmatism in a nearly hemispherical cavity is originally exploited to generate vortex array laser modes with the output power up to 300 mW. The inhomogeneous Helmholtz equation is employed to derive the wave function for manifesting the characteristics of the lasing modes. The theoretical wave function explicitly reveals the role of the Gouy phase in the formation of vortex arrays. Numerical analyses are further performed to confirm that the thermal lensing effect in the laser crystal assists the lasing transverse order to increase with increasing pump power. It is believed that the high efficiency enables the present laser modes to be useful in the applications of structured vortex beams. (C) 2020 Optical Society of America
Wed, 15 Jul 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/223762020-07-15T00:00:00ZExploiting a monolithic passively Q-switched Nd:YAG laser to mimic a single neuron cell under periodic stimulationhttp://scholars.ntou.edu.tw/handle/123456789/2545Title: Exploiting a monolithic passively Q-switched Nd:YAG laser to mimic a single neuron cell under periodic stimulation
Authors: Chen, Y. F.; Lee, C. C.; Hsiao, J. Q.; Huang, H. Y.; Tsou, C. H.; Hsing-Chin Liang; Huang, K. F.
Wed, 01 Jul 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/25452020-07-01T00:00:00ZTiming jitter reduction of passively Q-switched solid-state lasers by coupling resonance between pumping and firing rateshttp://scholars.ntou.edu.tw/handle/123456789/22370Title: Timing jitter reduction of passively Q-switched solid-state lasers by coupling resonance between pumping and firing rates
Authors: Chen, Y. F.; Chien, P. Y.; Lee, C. C.; Huang, K. F.; Liang, H. C.
Abstract: The coupling resonance between pumping and firing rates is originally proposed to achieve the timing jitter reduction of a Nd : YVO4 laser passively Q-switched with a saturable absorber. When the pumping rate is higher than the spontaneous emission rate, it is experimentally confirmed that the pulse firing rate can be fractionally locked with the pumping rate by controlling the pump power. The locking characteristics of the firing rate display a variety of complex plateaus that can be excellently manifested with the sine-circle map. From numerical analyses, the coupling strength can be verified to be effectively enhanced by reducing the duty cycle of the pumping rate. (C) 2020 Optical Society of America
Fri, 15 May 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/223702020-05-15T00:00:00ZTiming jitter reduction of passively Q-switched solid-state lasers by coupling resonance between pumping and firing rateshttp://scholars.ntou.edu.tw/handle/123456789/2542Title: Timing jitter reduction of passively Q-switched solid-state lasers by coupling resonance between pumping and firing rates
Authors: Chen, Y. F.; Chien, P. Y.; Lee, C. C.; Huang, K. F.; Hsing-Chin Liang
Fri, 01 May 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/25422020-05-01T00:00:00ZGeneration of resonant geometric modes from off-axis pumped degenerate cavity Nd:YVO4 lasers with external mode convertershttp://scholars.ntou.edu.tw/handle/123456789/22369Title: Generation of resonant geometric modes from off-axis pumped degenerate cavity Nd:YVO4 lasers with external mode converters
Authors: Liang, Hsing-Chih; Lin, Han-Yu
Abstract: We propose a theoretical model to generate the resonant geometric modes localized on ray periodic trajectories with orbital angular momentum. Based on the numerical analysis, we realize resonant geometric modes in the off-axis pumped degenerate cavity Nd:YVO4 lasers with an external mode converter. The experimental results reveal that laser output modes display the planar geometric modes when the off-axis displacement is sufficiently large, and the cavity length is set to satisfy the degenerate conditions. To generate the vortex beams, the planar geometric modes are transformed into circular geometric modes. Finally, the resonant geometric modes with large orbital angular momentum (OAM) can be generated from converting the circular geometric modes with an axicon lens. The experimental results are performed to approve the theoretical analyses. (C) 2020 Optical Society of America
Wed, 15 Apr 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/223692020-04-15T00:00:00ZCriterion for optimizing high-power acousto-optically Q-switched self-Raman yellow lasers with repetition rates up to 500 kHzhttp://scholars.ntou.edu.tw/handle/123456789/22368Title: Criterion for optimizing high-power acousto-optically Q-switched self-Raman yellow lasers with repetition rates up to 500 kHz
Authors: Chen, Y. F.; Chen, K. Y.; Liu, Y. C.; Chen, C. M.; Tsou, C. H.; Liang, H. C.
Abstract: The criterion for optimizing the high-power acousto-optically Q-switched self-Raman yellow laser is originally explored for the repetition rate within 100-500 kHz. The minimum allowed value for the gate-open time is experimentally verified to be determined by the pulse buildup time. By using the minimum allowed gate-open time, the highest conversion efficiency can be achieved to raise the output power by approximately 20% in comparison with the conventional results. At a repetition rate of 200 kHz, the maximum output power at 588 nm can be up to 8.8 W at an incident pump power of 26 W. Furthermore, a practical formula is developed to accurately calculate the threshold pump power as a function of the gate-open time for a given repetition rate. (C) 2020 Optical Society of America
Wed, 01 Apr 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/223682020-04-01T00:00:00ZCompact efficient high-power triple-color Nd:YVO4 yellow-lime-green self-Raman lasershttp://scholars.ntou.edu.tw/handle/123456789/22362Title: Compact efficient high-power triple-color Nd:YVO4 yellow-lime-green self-Raman lasers
Authors: Liu, Y. C.; Chen, C. M.; Hsiao, J. Q.; Pan, Y. Y.; Tsou, C. H.; Liang, H. C.; Chen, Y. F.
Abstract: A novel, to the best of our knowledge, approach is developed to realize a high-power compact efficient yellow-lime-green triple-color Nd : YVO4 self-Raman laser. The 588 nm yellow laser, the 559 nm lime laser, and the 532 nm green laser are converted from the 1064 nm fundamental wave and the 1176 nm Stokes Raman field. The simultaneous three-color operation is accomplished with three stages to step-by-step generate the 588 nm, 559 nm, and 532 nm lasers by using three different lithium triborate (LBO) crystals. By tuning the temperature of each individual LBO crystal, the 588 nm, 559 nm, and 532 nm output powers can be nearly the same and concurrently up to 2.4W at the incident pump power of 30 W, corresponding to a conversion efficiency of 24% for the total output power. (C) 2020 Optical Society of America
Sun, 01 Mar 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/223622020-03-01T00:00:00ZGeneration and characterization of burst modes in passively mode-locked lasers with internal Fabry-Perot cavitieshttp://scholars.ntou.edu.tw/handle/123456789/22355Title: Generation and characterization of burst modes in passively mode-locked lasers with internal Fabry-Perot cavities
Authors: Li, S. C.; Huang, T. L.; Hsieh, Y. H.; Liang, H. C.; Huang, K. F.; Chen, Y. F.
Abstract: The generation of burst pulses in a multi-pass passively mode-locked laser is systematically explored. We exploit intracavity mirrors with different thicknesses to serve as reflected Fabry-Perot (RFP) cavities in laser resonators. Using a RFP cavity with the thinnest optical thickness, we can generate picosecond optical burst pulses with the highest intra-burst pulse rate of 33.12 GHz. The maximum output power of 2.6 W is obtained at an incident pump power of 11.9 W. We further develop an analytical model which considers the RFP effects to manifest the first-order autocorrelation and spectral behaviors in experiments. The agreement between theoretical analyses and experimental explorations provides the feasibility to flexibly manipulate the burst modes in practical applications. (C) 2019 Optical Society of America
Wed, 01 Jan 2020 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/223552020-01-01T00:00:00ZOrigin of continuous curves and dotted spots in laser transverse modes with geometric structureshttp://scholars.ntou.edu.tw/handle/123456789/22459Title: Origin of continuous curves and dotted spots in laser transverse modes with geometric structures
Authors: Chen, Y. F.; Tung, J. C.; Hsieh, M. X.; Hsieh, Y. H.; Liang, H. C.; Huang, K. F.
Abstract: The transverse structures of geometric modes in degenerate laser resonators with large astigmatism are systematically investigated by starting from the Gaussian wave packet formulation with ray-wave connections. The overlapping degree D between Gaussian wave packets is derived as an analytic expression that manifests the critical overlapping with D = 1. The transverse patterns are confirmed to display a structure of continuous curves or dotted spots, depending on D > 1 or D < 1, respectively. A thorough comparison between experimental results and numerical calculations is performed to validate the theoretical analysis. (C) 2019 Optical Society of America
Sun, 15 Dec 2019 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/224592019-12-15T00:00:00ZGenerating High-Order Transverse Patterns in Optically Pumped Semiconductor Lasershttp://scholars.ntou.edu.tw/handle/123456789/22451Title: Generating High-Order Transverse Patterns in Optically Pumped Semiconductor Lasers
Authors: Tuan, Pi-Hui; Hsieh, Yen-Hui; Tu, Chin-Wei; Lee, Chi-Chun; Tsou, Chia-Han; Liang, Hsin-Chih; Huang, Kai-Feng; Chen, Yung-Fu
Abstract: High-order pattern formation in an optically pumped semiconductor laser (OPSL) under a selective pumping with varying spatial overlap between the pump beam and transverse modes is explored. In contrast to transverse pattern generation by off-axis pumped solid-state lasers where the mode order can be flexibly increased, experimental results reveal that the selective pumping fails to realize high-order mode operation in OPSLs when the pump-to-mode size ratio and pump power are insufficiently large. On the other hand, several high-order patterns belonging to the Hermite-Laguerre-Gaussian (HLG) modes are observed when scanning a large-ratio pump beam to specific positions on the gain chip. These HLG modes are experimentally confirmed to mainly originate from the transverse non-uniformity of present OPSL chip, while their structural features cannot be simply correlated with the pump scanning positions. Nevertheless, it is believed that the first-time observation of pure HLG modes under the large-ratio pumping can offer useful insights into the high-order pattern manipulation in OPSLs.
Fri, 01 Nov 2019 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/224512019-11-01T00:00:00ZGeneralized wave-packet formulation with ray-wave connections for geometric modes in degenerate astigmatic laser resonatorshttp://scholars.ntou.edu.tw/handle/123456789/22450Title: Generalized wave-packet formulation with ray-wave connections for geometric modes in degenerate astigmatic laser resonators
Authors: Chen, Y. F.; Tung, J. C.; Hsieh, M. X.; Hsieh, Y. H.; Liang, H. C.; Huang, K. F.
Abstract: The parametric equations for periodic rays in degenerate astigmatic laser resonators are derived in a generalized way. The derived parametric equations clearly reveal the formation of Lissajous geometric modes with phase variation along the propagation. Using the representation of a quantum coherent state, a generalized wave-packet formula is derived to connect with the periodic rays of geometric modes. The derived wave-packet formula is not only validated through comparing with various experimental patterns, but also is directly exploited to manifest the spatial asymmetries of Lissajous lasing modes due to a highly transmissive output coupler. (C) 2019 Optical Society of America
Fri, 01 Nov 2019 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/224502019-11-01T00:00:00ZHigh-power dual-color yellow-green solid-state self-Raman laserhttp://scholars.ntou.edu.tw/handle/123456789/2549Title: High-power dual-color yellow-green solid-state self-Raman laser
Authors: Chen, Y. F.; Liu, Y. C.; Gu, D. Y.; Pan, Y. Y.; Cheng, H. P.; Tsou, C. H.; Hsing-Chin Liang
Mon, 01 Jul 2019 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/25492019-07-01T00:00:00ZLaser wave-packet representation to unify eigenmodes and geometric modes in spherical cavitieshttp://scholars.ntou.edu.tw/handle/123456789/22434Title: Laser wave-packet representation to unify eigenmodes and geometric modes in spherical cavities
Authors: Chen, Y. F.; Li, S. C.; Hsieh, Y. H.; Tung, J. C.; Liang, H. C.; Huang, K. F.
Abstract: In terms of the Gaussian beam parameter and Gouy phase, the parametric equations for geometric rays of periodic orbits in spherical resonators are originally generalized as the real parts of polar forms. The derived polar forms are employed to create an analytical wave-packet representation for unifying the ray and wave. The developed wave-packet representation can concurrently manifest the geometric modes and eigenmodes in the degenerate and nondegenerate cavities. Complete comparisons with experimental data are made not only to verify the derived wave-packet representation, but also to disclose the transition from the eigenmodes to geometric modes by increasing the transverse order in a degenerate cavity. (c) 2019 Optical Society of America.
Sat, 01 Jun 2019 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/224342019-06-01T00:00:00ZWave representation for asymmetric elliptic vortex beams generated from the astigmatic mode converterhttp://scholars.ntou.edu.tw/handle/123456789/22425Title: Wave representation for asymmetric elliptic vortex beams generated from the astigmatic mode converter
Authors: Chen, Y. F.; Lai, Y. H.; Hsieh, M. X.; Hsieh, Y. H.; Tu, C. W.; Liang, H. C.; Huang, K. F.
Abstract: An analytical wave representation is derived to express the asymmetric elliptic vortex beams generated by using an astigmatic mode converter to transform the asymmetric Hermite-Gaussian modes. The effect of the spatial asymmetry on the elliptic vortex beam can be straight forwardly considered in the analytical wave representation. A detailed comparison with experimental intensity patterns and phase structures is made. The good agreement between experimental results and theoretical analyses confirms the characterization and generation of the asymmetric elliptic vortex beams. (C) 2019 Optical Society of America
Mon, 15 Apr 2019 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/224252019-04-15T00:00:00ZEfficient high-power dual-wavelength lime-green Nd:YVO4 lasershttp://scholars.ntou.edu.tw/handle/123456789/22419Title: Efficient high-power dual-wavelength lime-green Nd:YVO4 lasers
Authors: Chen, Y. F.; Liu, Y. C.; Pan, Y. Y.; Gu, D. Y.; Cheng, H. P.; Tsou, C. H.; Liang, H. C.
Abstract: An efficient high-power dual-wavelength lime-green Nd:YVO4 self-Raman laser is inventively developed by using two different lithium triborate (LBO) crystals. The first and second LBO crystals are employed to generate the 559 nm lime and 532 nm green lasers, respectively. The temperature of the first LBO crystal is fixed at the optimal phase matching, whereas the temperature of the second LBO crystal is tuned to flexibly control the relative strengths between the 532 and 559 nm waves. When the temperature of the second LBO crystal is set for the maximal total output power, the 532 and 559 nm output powers, respectively, are 7.1 and 2.9 W at a pump power of 31.6 W, corresponding to a conversion efficiency of 31.6%. When the temperature is controlled for the balanced output, the 532 and 559 nm powers, respectively, are 4.3 and 4.2 W at a pump power of 31.6 W, corresponding to a conversion efficiency of 26.9%. (C) 2019 Optical Society of America
Fri, 15 Mar 2019 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/224192019-03-15T00:00:00ZEfficient high-power dual-wavelength lime-green Nd:YVO4 lasershttp://scholars.ntou.edu.tw/handle/123456789/2550Title: Efficient high-power dual-wavelength lime-green Nd:YVO4 lasers
Authors: Chen, Y. F.; Liu, Y. C.; Pan, Y. Y.; Gu, D. Y.; Cheng, H. P.; Tsou, C. H.; Hsing-Chin Liang
Fri, 01 Mar 2019 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/25502019-03-01T00:00:00ZExploring elliptical vortex beams with the spatial damping effecthttp://scholars.ntou.edu.tw/handle/123456789/22418Title: Exploring elliptical vortex beams with the spatial damping effect
Authors: Chen, Y. F.; Hsieh, M. X.; Lai, Y. H.; Hsieh, Y. H.; Tu, C. W.; Liang, H. C.; Huang, K. F.
Abstract: A general integral formula is analytically derived to represent the wave function of elliptical vortex modes. The derived formula can be straightforwardly employed to take account of spatial damping to explore vortex structure. Spatial damping is found to cause the central degenerate singularity of the circular vortex mode to be split into several singularities with different topological charges. For the non-circular vortex beam, the influence of spatial damping on the distribution of singularities is not significant. Theoretical analyses are confirmed to agree very well with the experimental measurements. (C) 2019 Optical Society of America
Fri, 15 Feb 2019 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/224182019-02-15T00:00:00ZEfficient high-power continuous-wave lasers at green-lime-yellow wavelengths by using a Nd:YVO4 self-Raman crystalhttp://scholars.ntou.edu.tw/handle/123456789/22416Title: Efficient high-power continuous-wave lasers at green-lime-yellow wavelengths by using a Nd:YVO4 self-Raman crystal
Authors: Chen, Y. F.; Pan, Y. Y.; Liu, Y. C.; Cheng, H. P.; Tsou, C. H.; Liang, H. C.
Abstract: Efficient high-power continuous-wave Nd:YVO4 visible lasers at versatile wavelengths of 532 (green). 559 (lime). and 588 nm (yellow) are demonstrated to be achieved by using the identical cavity mirrors and gain medium. A dichroic coating is deposited on one end surface of the gain medium to gather the backward green-yellow emission. The green. lime. and yellow outputs are individually optimized by using different phase-matched lithium triborate (LBO) crystals for second harmonic generation (SHG) of the fundamental field, sum frequency generation (SFG) of the fundamental and the stimulated Raman fields. and SHG of the stimulated Raman field, respectively. At a pump power of 31.6 W, the output powers at 532, 559, and 588 nm can be up to 6.8. 5.4. and 3.1 W. The high efficient and compact Nd:YVO4 lasers at green-lime-yellow wavelengths can be potentially beneficial to future applications in retinal photocoagulation. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Mon, 04 Feb 2019 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/224162019-02-04T00:00:00ZNarrowing spectral linewidth in passively mode-locked solid-state lasershttp://scholars.ntou.edu.tw/handle/123456789/2562Title: Narrowing spectral linewidth in passively mode-locked solid-state lasers
Authors: Huang, T. L.; Li, S. C.; Tsou, C. H.; Hsing-Chin Liang; Huang, K. F.; Chen, Y. F.
Sat, 01 Dec 2018 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/25622018-12-01T00:00:00ZInvestigation of the antiphase dynamics of the orthogonally polarized passively Q-switched Nd:YLF laserhttp://scholars.ntou.edu.tw/handle/123456789/2577Title: Investigation of the antiphase dynamics of the orthogonally polarized passively Q-switched Nd:YLF laser
Authors: Hsing-Chin Liang; Li, D.; Lin, E. H.; Hsu, C. C.; Lin, H. Y.
Mon, 01 Oct 2018 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/25772018-10-01T00:00:00ZOrthogonally polarized single-longitudinal-mode operation in a dual-wavelength monolithic Nd:YAG laser at 1319 nm and 1338 nmhttp://scholars.ntou.edu.tw/handle/123456789/2556Title: Orthogonally polarized single-longitudinal-mode operation in a dual-wavelength monolithic Nd:YAG laser at 1319 nm and 1338 nm
Authors: Cheng, H. P.; Liu, Y. C.; Huang, T. L.; Hsing-Chin Liang; Chen, Y. F.
Wed, 01 Aug 2018 00:00:00 GMThttp://scholars.ntou.edu.tw/handle/123456789/25562018-08-01T00:00:00Z