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Tangentially and radially polarized Nd:YAG hollow lasers with two pairs of axicons
摘要： We present a novel method for generating tangentially and radially polarized laser radiations by using two pairs of positive and negative axicons. Tangentially and radially polarized diode-pumped Nd:YAG hollow lasers were demonstrated respectively. At an incident pump power of 17.8 W, the output power of tangentially and radially polarized laser beam is 6.9 W and 8.6 W, respectively. Polarization purity of tangentially and radially polarized laser beam is 99.2% and 98.7%, respectively. The experimental results reveal that tangentially and radially polarized laser beams with high polarization purity can be generated by resonator cavity consisting of only axicons. To the best of our knowledge, this is the first time that the cylindrical vector laser beam was realized only by axicons.
关键词： Solid-state laser,Radially polarized,Tangentially polarized,Axicons
更新于2025-09-23 15:21:01
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Control of the photoluminescence properties of Nd:YAG crystals by laser irradiation
摘要： This paper presents luminescence properties of Nd:YAG crystal defects including oxygen vacancy, O-hole center, F and F+ centers. The Nd:YAG crystal defects have photoluminescence emission peaks in the ~ 350-500 nm range of UV-Vis spectral region. The results show that laser irradiation can control photoluminescence properties of the Nd:YAG crystal samples. Our results can be very important in solid state laser and surface engineering.
关键词： solid state laser,laser irradiation,crystal defects,photoluminescence,Nd:YAG
更新于2025-09-19 17:13:59
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Stable pulse output of a diode-pumped Tm:YAP laser based on the longitudinal mode beating effect
摘要： We successfully demonstrate the stable pulse output of a diode-end-pumped Tm:YAP laser based on the longitudinal mode beating technique. Without any additional modulation elements in the cavity, the stable pulse output of a Tm:YAP laser at 1937 nm is achieved. At an absorbed pump power of 6 W, the average output power of 1.14 W is obtained with a slope efficiency of 23%, and the pulse duration is 5.3 ns with a pulse repetition frequency of 89 MHz. To the best of our knowledge, this is the first 2 μm self-pulsing solid-state laser based on the longitudinal mode beating effect.
关键词： self-pulsing laser,diode pumped lasers,all-solid-state laser,Tm:YAP
更新于2025-09-19 17:13:59
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Laser performance of high repetition frequency on a 970 nm LD side-pumped Er:YSGG crystal operated at 2.79 ??m
摘要： We demonstrate laser performance of high repetition frequency on 970 nm laser diodes side-pumped Er:YSGG crystal rod with concave end faces. The laser performance under different repetition rates and pulse widths was studied with an optimal cavity length. The maximum average output power of 11.81 W operated at a repetition frequency of 500 Hz and 2.79 μm was achieved, corresponding to the slope efficiency of 10.49%. In addition, the beam quality factors M2x/M2y of 7.01/7.10 and far-field divergences Θx/Θy of 9.15/9.18 mrad were also obtained under the high repetition frequency of 500 Hz. These results show that the LD side-pumped Er:YSGG laser crystal rod with concave end faces has the potential of being operated under high repetition frequency.
关键词： Er:YSGG,high repetition frequency,Solid-state laser,concave end face
更新于2025-09-19 17:13:59
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Powerful transversally diode-pumped Nd:YAG laser with low depolarization losses
摘要： The optical losses introduced into the cavity of transversally diode pumped Nd:YAG lasers operating in the linearly polarized Q-switched mode by the induced birefringence were evaluated. The relationship between the loss values and the state of the side surface of laser active elements was established. It has been shown that the active elements with adhesive light-scattering layers on their side surfaces make it possible to create the laser sources not only with a high degree of uniformity of the distribution of radiation within the output beam cross-section, but also with a low level of the optical depolarization losses.
关键词： Solid-state laser,Transversal diode pumping,Depolarization optical losses,Induced birefringence
更新于2025-09-19 17:13:59
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Influence of Fluorescence to Photon Lifetime Ratio on Detection Sensitivity in Laser Self-Mixing Interferometry
摘要： Laser self-mixing interferometry (SMI) has been widely applied in the fields of precision measurement in scientific research, industry and biomedicine, and most researchers preferentially utilize laser diodes (LD) as light sources due to their compact structure and low cost. In most SMI cases, detection sensitivity rather than structure and cost is always the first concern. So in this article, we concentrate on an influencing factor on detection sensitivity named fluorescence to photon lifetime ratio (FPLR) which is an inherent parameter of the active material in a laser cavity. Derivation and simulation based on the time delayed rate equations are followed to validate the significant role played by the FPLR, then experiments according to different laser types including solid state lasers (SSL) and LDs are implemented to further prove the factor mentioned. Results demonstrate that SSLs always have higher detection sensitivity to feedback light than LDs, and is always more suitable to be applied in precision measurement. Additionally, the Yb:YAG laser is more sensitive than the Nd:YAG one. Increasing the pumping level from the threshold will decrease the SMI signal’s sensitivity, and reducing laser feedback strength will also decrease the SMI signal’s sensitivity. The findings from this article are beneficial to studying laser feedback sensitivity and selecting appropriate laser types in designing SMI sensors or instruments. Though with the disadvantages of large size and high cost, SSLs may be more suitable light sources in the field of high performance SMI sensing if miniaturization and cost are not the significant consideration.
关键词： sensitivity,laser diode,fluorescence to photon lifetime ratio,Laser self-mixing interferometry,solid state laser
更新于2025-09-16 10:30:52
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THE TEMPORARY CHARACTERISTICS OF VACUUM DISCHARGE WITH LASER IGNITION
摘要： A study was made of the switching process of a vacuum discharger ignited by a pulsed solid-state laser operating in the Q-switched mode. The dependence of the response time on the energy of the igniting pulse of laser radiation and the thermodynamic characteristics of the target material has been demonstrated. On the basis of the experimental data, it was suggested that under the action of a laser pulse in the erosion products of the electrodes an initial glow discharge is ignited, which, as a result of the development of ionization-superheating instability, undergoes a contraction of the current channel and turns into an arc channel.
关键词： vacuum discharge,laser ignition,switching process,Q-switched mode,glow discharge,arc channel,solid-state laser,thermodynamic characteristics
更新于2025-09-16 10:30:52
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Continuous-wave laser performance of 10 at% Yb:YSAG transparent ceramics
摘要： We report on the continuous-wave and tunable laser operation of transparent 10 at% Yb:Y3Sc1.5Al3.5O12 (Yb:YSAG) ceramics, which have a dense and homogenous microstructure after being sintered at 1820 °C for 10 h. The Yb:YSAG ceramics have excellent optical in-line transmittance characteristics. The broad absorption and emission spectra of Yb:YSAG demonstrated that these ceramics are suitable for laser-diode pumping solid-state lasers. For the 2-mm thick ceramic, a continuous-wave output power of 1.79 W at 1031 nm was measured with a slope ef?ciency of 18.3%, and a smooth tunable spectra ranging from 1021 nm to 1040 nm has been obtained, with a tunable wavelength exceeding approximately 19 nm.
关键词： laser materials,ceramic,solid-state laser
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Photothermal Gas Detection of CO <sub/>2</sub> in an Intracavity Solid-State Laser Configuration
摘要： Laser spectroscopy has proven to be a powerful tool for quantitative and selective measurements of gas samples. Numerous techniques have been developed throughout the recent decades. This progress has been driven mostly by the growing demand on sensitive sensors, also for out-of-lab applications. Here we describe a new gas detection technique, which relies on photo-thermal (PT) effects. In PT spectroscopy the gas sample concentration can be derived by measuring a change in the refractive index (RI) of the excited gas particles. This is usually achieved by exciting the gas particles using a radiation source and by measuring the small variations of the RI (usually in the range of 10-5), e.g. in an interferometric sensor configuration, which is complicated and prone to mechanical and acoustic noise. Moreover, appropriate construction of a PT sensor enables encoding the gas concentration into frequency variations (similarly to dispersion spectroscopy), which provides a baseline-free measurement. Here we propose a novel, patent-pending configuration, which is non-complex, cost effective, miniaturized and offers detection limits at least comparable with other methods, having similar complexity, e.g. quartz enhanced photo-acoustic spectroscopy. Base of the sensor is a standard configuration of a monolithic, solid-state laser based on Nd:YVO4 active crystal and a YVO4 birefringent crystal ensuring single polarization operation of the laser at 1064 nm. To enable implementing PT gas detection an intentional air-gap has been obtained inside the resonator by separating the output mirror with a 2x2x2mm3 quartz crystal. In this particular experiment the air gap was filled with CO2 under ambient pressure and excited with an auxiliary fiber laser targeting a strong absorption line localized at 2003,5 nm. Due to the PT effect the density of the excited gas changes, which results in a change of its RI. A change of RI inside the solid-state laser resonator results in a slight variation of the optical pathlength and hence is directly translated to frequency changes of emission of the solid-state laser. The optical frequency changes are detected in a heterodyne configuration (the reference laser emission was obtained in the same crystal structure to minimise noise; the gas is excited in the path of only one of the emissions). The 2 μm excitation laser was modulated with a f0=1 kHz sinewave function and tuned across the absorption line. The induced PT effect was conveniently filtered-out at 2xf0 using a lock-in amplifier. The schematic of the sensor configuration, along with 2f signal registered for a 1000 ppmv and 200 ppmv CO2 sample is depicted in figure 1.
关键词： photothermal gas detection,refractive index,intracavity solid-state laser,CO2,heterodyne configuration
更新于2025-09-16 10:30:52
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A 142 W Ho:YAG laser single-end-pumped by a Tm-doped fiber laser at 1931 nm
摘要： In this paper, a high-power Ho:YAG laser in-band pumped by a Tm-doped fiber laser at 1931 nm is reported. A maximum output power of 142.2 W is achieved at 2091 nm using a single-end-pumped configuration, corresponding to a slope efficiency of 56.7%. This is, to the best of our knowledge, the highest output power directly generated by bulk Ho-oscillators in the 2.1 μm spectral region.
关键词： fiber laser,Ho:YAG,solid state laser
更新于2025-09-12 10:27:22