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ABSTRACT: A parameter x is introduced to characterize the strength of thermal lens spherical aberration, whose influences on resonator's stable zones are analyzed theoretically. Some new and helpful results are obtained. For symmetrical plane-plane cavity, spherical aberration has just influence on the back edge of stable zone. For asymmetrical plane-plane cavity, spherical aberration has influence on the back edges of the two stable zones and the front edge of the second stable zone. Effects of transverse mode collapsing to TEM00 mode and stable zones separation of different order's transverse modes are pointed out, which is the foundation of TEM00 mode output power scaling for solid state laser oscillator. Influences of parameters such as resonator's long arm length, short arm length, and pump beam radius on the extent to which of stable zones separation of different order transverse modes are discussed. An experimental setup of a high power diodes dual-end pumped Nd:YVO4 TEM00 mode laser oscillator is built up and investigated experimentally. 51.2 W TEM00 mode output power in CW operation is achieved with an optical-to-optical efficiency of about 50% and beam quality factor M2 being 1.2.
Optics Express 05/2012; 20(10):10605-16. · 3.59 Impact Factor
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ABSTRACT: In end-pumped Nd:YVO₄ amplifiers, beam quality improvement is obtained both in theory and in experiments. A theoretical model of gain-guided laser amplifier is developed by comprehensively considering thermal effect, gain guiding and gain saturation effect. Several key parameters of the amplifier are discussed such as the input beam quality, the beam filling factor between input beam and pump beam, the ratio between input power and pump power, and the length of laser crystal. The theoretical results are confirmed by the experiments.
Optics Express 10/2011; 19(21):21060-73. · 3.59 Impact Factor
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ABSTRACT: Glare is a major factor of influencing visual capacity, and the recovery time of the human eye after glaring is the most important evaluation standard. Now the research of glare refers to the normal illuminance source. With the experiment of the recovery time after strong exposure glaring, the relation of the influence factor is discussed. The formula calculating the recovery time is corrected with the experiment data. An objective method is raised for the glare evaluation of strong exposure.
BioMedical Engineering and Informatics, 2008. BMEI 2008. International Conference on; 06/2008
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ABSTRACT: External cavity feedback for a broad-area laser diode (BAL) with antireflection coating on the front facet is investigated experimentally. The feedback is created by a high-reflection mirror and a blazed grating, which reflect two parts of the laser emission back to the BAL, thereby forming an external resonator. When a Fabry–Perot etalon was inserted into the resonator an output beam with a bandwidth of 0.02 nm and power of 150 mW was obtained. The beam diffraction limited factor amounted to M2=1.16.
Applied Physics Letters 07/2004; 85(4):525-527. · 3.84 Impact Factor
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ABSTRACT: Spherical aberrations of thermal lens of the active media are severe when the solid state lasers are strongly pumped. The aberrations influence the mode profile, the diffraction loss, the output power and other laser beam properties, especially for a dynamically stable resonator with large TEM00-mode volume. Self-consistent modes in a resonator with aberrations are calculated using Fox–Li diffraction iterative algorithm. There are side lobes with the fundamental mode when the spherical aberration is introduced, hence the beam quality is deteriorated. The calculated results agree well with the experimental data. The beam filling factor plays an important role in the design of a laser system. The optimum value of the beam filling factor should be determined by the experimental results according to the spherical aberration effect.
Optics Communications 281(20):5222-5228. · 1.49 Impact Factor
