Application of plasma shutter in second harmonic generation of AgGaSe2 crystal

A reliable target-triggering plasma shutter was applied to second harmonic generation (SHG) of AgGaSe2 crystal with a TEA CO2 laser. Under normal air pressure, argon charged plasma shutter was triggered by focusing beam companying with a pair of adjustable metal targets. Conversion efficiency was enhanced by 3.3 times and the maximal efficiency 9.3%, with 1.4-mJ second harmonic energy was obtained. Finally, crystal damage was discussed together with previous work.     

可调谐TEA CO2激光倍频的研究

近年来,随着3～5 μm大气窗口热成像系统的开发和应用,国际上正大力展开这一波段激光光源的研究.迄今在3～5 μm波段尚无直接振荡的小型且操作简便的高功率激光器,人们致力于利用波长转换技术来获得这一波段相干光的开发研究.其中,最引人注目的是利用非线性晶体的TEA CO2 激光倍频的研究.我们利用自行研制的小型可调谐TEA CO2激光器和中科院安徽光机所生长的尺寸为7×8×12 mm3的AgGaSe2晶体,实现了CO2激光的倍频.TEA CO2激光器可输出50多条谱线,输出能量大于50 mJ.AgGaSe2晶体采用I型相位匹配,在CO2激光10.59 μm波长下,其相位匹配角为55.43°.实验中采用改变抽运光入射角的方法获得了20多条CO2激光谱线的倍频光输出,其中在CO2激光的10 P(18)谱线下得到较大倍频光输出1.32 mJ.(OB8)     

TEACO2激光器倍频研究的进展

综述了激光倍频技术的发展，并对TEA CO2激光器倍频技术进行了较为详细的分析。给出了3-5μm激光的应用领域。     

面向创新型人才培养的光信息科学与技术专业实践教学体系改革

社会信息化的发展要求不断变化和提高光信息人才,这就要求光信息科学与技术专业应从实践能力培养的目标出发,以深化基础教学、注重实践能力、鼓励创新思维作为指导思想,加强校内外实践教学环节的实效性,注重建立高素质的实践教师队伍和完善科学的实践教学考核方法,努力构建创新人才培养的实践教学培养体系。     

TEA CO2激光在AgGaSe2晶体中的倍频实验研究

实验上实现了TEACO2 激光在AgGaSe2 非线性光学晶体中的倍频光产生。着重研究了TEACO2 激光的能量、脉冲重复频率以及基波的焦点位置对于倍频光输出的影响。实验中得到了倍频光的角度调谐曲线 ,将入射光聚焦在晶体的中心区域 ,获得最大倍频光输出能量为 1 32mJ。脉冲能量转换效率为 2 4 % ,主脉冲的最大转换效率为 4 %。还分析了脉冲重复频率的变化 ( <10Hz)对倍频转换效率的影响。实验结果发现抑制倍频转换效率的主要因素为晶体的光学质量、激光脉冲低功率密度的拖尾以及激光脉冲的不稳定。特别由于脉冲附带长的拖尾加剧了热透镜效应 ,使得脉冲重复频率的增加引起转换效率的降低。     

BBO晶体倍频中的温度场与光场耦合模拟

首先建立了无限大晶体截面近似下的时-空4维光场和温度场耦合的倍频模型. 并在瓦级功率激光抽运下,利用解析公式和迭代方法数值模拟了BBO晶体内的倍频过程.得到了基频光和倍频光的振幅和转换效率曲线以及温度场分布,展示了温度场及光场的时间演化过程. 其次分析了抽运功率和晶体长度对转换效率和温度场的影响. 结果给出,温度分布对转换效率和光束质量都有较大影响;对热效应引起的相位失配进行补偿能够很好地改善转换效率的下降,因此必须在实际应用中加以考虑. 关键词： 倍频 温度场 BBO晶体     

Optical properties and phase-matching in LiInS2

Investigation results on linear and non-linear optical properties, damage threshold and potential efficiencies of biaxial negative LiInS2 crystal are represented. It shows that the crystal has phase-matching and group-velocity matching in wide spectral range for second harmonic, sum- and difference-frequency generation of visible, near and middle IR lasers. The possibilities of designing middle IR optical parametric oscillator (OPO) pumped by Nd:YAG and dye lasers and specially possibility of frequency conversion with 3 um range femtosecond erbium lasers are given.     

小型可调谐TEA CO2激光的二次谐波产生

利用国产的、尺寸为 7mm× 8mm× 12mm的AgGaSe2 晶体 ,实现了可调谐TEACO2 激光的二次谐波产生 ,得到了CO2 激光 10 .6 μm和 9.6 μm谱带的 12条谱线的二次谐波。最大的二次谐波输出能量达到 1.32mJ[10P(16 )谱线 ]。在 10P(18)谱线处获得的最大能量转换效率为 4%。     

掺杂晶体Cd0.35Hg0.65Ga2S4的光学特性

研究了掺杂非线性晶体Cd0.35Hg0.65Ga2S4的线性和非线性光学特性以及相位匹配.在相同的实验条件下，与已知的中红外晶体相比较，测定了该晶体的损伤阈值.实现了CO2激光二次谐波产生实验，与理论预测相一致. 关键词： 掺杂非线性晶体 Cd0.35Hg0.65Ga2S4 二次谐波产生 CO2激光     

Properties of periodic multicrystal configurations in walk-off-compensating second harmonic generation of ultrashort pulses

This work designs a four-platelet periodic multicrystal configuration in the second harmonic generation of ultra-short pulses as a new walk-off-compensating device. It theoretically investigates a proposed active and a typical passive compensating scheme with the undepleted-pump approximation. The result shows that the angular and spectral band-widths are proportional to the number of crystal pairs as expected,but the temperature tunability is basically unaltered owing to inter-plate pulse interference. At the same time,an analysis reveals that a misuse of the phase mismatch factor is responsible for a historic controversy about pulse interference. A real design of an ultraviolet second harmonic generation (262.5 nm) is considered in a passive periodic β-Barium Borate-calcite configuration,where the inter-plate pulse interference is found to form an azimuthal tuning restriction and to lower plate length tolerance. A subsequent numerical simulation with pump depletion is in good accordance with theoretical prediction.