High-Efficiency Mid-Infrared Picosecond MgO:PPLN Single Resonant Optical Parametric Oscillator

We demonstrate a high-emciency mid-infrared picosecond optical parametric oscillator （OPO） based on MgO doped periodically poled lithium niobate （MgO：PPLN） with a laser diode array （LDA） pumped Innoslab amplifier as the pumping source. Under a 16 W synchronously pumping power, 4.5 W of idler light at 2896nm is obtained. A tuning range of idler light from 2688nm to 3016nm is achieved, within which the highest optical-optical conversion ettlciency from pump power to OPO output is 35.1%. Moreover, a signal light of -500mW from 1644 to 1700nm with a repetition rate of 233.8 MHz is generated.

Widely Tunable Middle Infrared Optical Parametric Oscillator Pumped by the Q-Switched Ho：GdVO_4 Laser

We demonstrate a middle infrared ZnGeP_2 optical parametric oscillator pumped by the Q-switched Ho：GdVO_4 laser. When the incident Ho pump power is 4.12 W, the maximum average output power of the ZGP-OPO laser is 2.05 W, corresponding to a slope efficiency of 74.6%. The ZGP-OPO laser produces 4.2 ns mid-infrared pulses at a pulse repetition rate of 5 kHz. In addition, we obtain 0.8 um of tunable range for the signal wave and 2.1 um of tunable range for the idler wave.

Optimization of the idler wavelength tunable cascaded optical parametric oscillator based on chirp-assisted aperiodically poled lithium niobate crystal

We present the numerical results for the optimization of the pump-to-idler conversion efficiencies of nanosecond idler wavelength tunable cascaded optical parametric oscillators （OPO） in different wavelength tuning ranges, where the primary signals from the OPO process are recycled to enhance the pump-to-idler conversion efficiencies via the simultaneous dif- ference frequency generation （DFG） process by monolithic aperiodically poled, magnesium oxide doped lithium niobate （APMgLN） crystals. The APMgLN crystals are designed with different chirp parameters for the DFG process to broaden their thermal acceptance bandwidths to different extents. The idler wavelength tuning of the cascaded OPO is realized by changing the temperature of the designed APMgLN crystal and the cascaded oscillation is achieved in a single pump pass singly resonant linear cavity. The pump-to-idler conversion efficiencies with respect to the pump pulse duration and ratio of OPO coefficient to DFG coefficient are calculated by numerically solving the coupled wave equations. The optimal work- ing conditions of the tunable cascaded OPOs pumped by pulses with energies of 350 p_J and 700 ~J are compared to obtain the general rules of optimization. It is concluded that the optimization becomes the interplay between the ratio of OPO coefficient to DFG coefficient and the pump pulse duration when the idler wavelength tuning range and the pump pulse energy are fixed. Besides, higher pump pulse energy is beneficial for reaching higher optimal pump-to-idler conversion efficiency as long as the APMgLN crystal is optimized according to this pump condition. To the best of our knowledge, this is the first numerical analysis of idler wavelength tunable cascaded OPOs based on chirp-assisted APMgLN crystals.

A Mid-IR Optical Parametric Oscillator Pumped by an Actively Q-Switched Ho:YAG Ceramic Laser

We demonstrate a mid-IR ZnGeP2 （ZGP） optical parametric oscillator （OPO） pumped by a dual-end-pumped actively aeoasto-optie Q-switched Ho：YAG ceramic laser. The maximum average output power of 35 W is obtained at a pulse repetition frequency of 20 kHz from the Ho：YAG ceramic laser. Under the maximum incident pump power of Ho：YAG ceramic laser, the maximum output power of 14 W is obtained from the ZGP OPO, corresponding to the slope efficiency of 49.6% with respect to the incident pump power. The wavelength can be tuned from 3.5 μm to 4.2μm （signal）, corresponding to 5.24.1 μm （idler）. The beam quality M2 is less than 2.3 from the ZGP OPO.

Mid-infrared optical parametric oscillator based on ZnGeP_2 pumped by 2-μm laser

We present a 3 5 μ m optical parametric oscillator （OPO） based on ZGP pumped by KTP OPO 2.1-μ m laser. The tuning curves of ZGP OPO are calculated. The 8 ×6 ×18 （mm） ZGP crystal, whose end faces are antireflection coated at 2.1 and 3.7 4.6 μ m, is cut as θ =53.5°, φ =0°. When the pump power of 2.1-μ m polarized laser is 15 W at 8 kHz, 5.7-W output power and 46.6% slope efficiency are obtained with a ZGP type I phase match. Central wavelengths of the signal and idler lasers are 4.10 and 4.32 μ m, respectively. Pulse duration is about 27 ns. Beam quality factor M 2 is better than 1.8. The tunability of 3 5 μ m can be achieved by changing the angle of the ZGP crystal.

13.5 mJ polarized 2.09μm fiber-bulk holmium laser and its application to a mid-infrared ZnGeP2 optical parametric oscillator

A high pulse repetition frequency（PRF）, high energy Ho：YAG laser directly pumped by a Tm-doped fiber laser and its application to a mid-infrared ZnGeP_2（ZGP） optical parametric oscillator（OPO） is demonstrated.The maximum polarized 2.09 μm laser pulse energy is 13.46 mJ at a PRF of 1 k Hz. The corresponding peak power reaches 504 kW. In a double-resonant ZGP-OPO, a maximum mid-infrared laser pulse energy of 1.25 m J,corresponding to a peak power of 79 kW, is accomplished at a PRF of 3 kHz. The nonlinear conversion efficiency reaches 41.7%. The nonlinear slope efficiency reaches 53.3%.

Highly efficient H-β Fraunhofer line optical parametric oscillator pumped by a single-frequency 355 nm laser

A highly efficient laser system output at the H-13 Fraunhofer line of 486.1 nm has been demonstrated. A high pulse energy single-frequency hybrid 1064 nm master oscillator power amplifier was frequency-tripled to achieve 355 nm laser pulses, which acted as the pmnp source of the beta barium borate nanosecond pulse optical para- metric oscillator. With pump energy of 190 mJ, the laser system generated a maximum output of 62 mJ blue laser pulses at 486.1 nm, corresponding to conversion efficiency of 32.6%. The laser spectrum width was measured to be around 0.1 ran, being in conformity with the spectrum width of the solar Fraunhofer line.

Injection-seeded single frequency 2.05μm output by ring cavity optical parametric oscillator

An injection-seeded single-resonant optical parametric oscillator（SROPO） with single frequency nanosecond pulsed 2.05 μm wavelength output is presented. Based on two potassium titanyl phosphate crystals and pumped by a 1064 nm single frequency laser pulse, injection seeding is performed successfully by using the ramp-hold-fire technique in a ring cavity with a bow-tie configuration. The SROPO provides 2.65 m J single frequency signal pulse output with a 17.6 ns pulse duration at a 20 Hz repetition rate. A near-diffraction-limited beam is achieved with a beam quality factor M^2 of about 1.2. The spectrum linewidth of the signal pulse is around 26.4 MHz,which is almost the Fourier-transform-limited value.

棱镜腔技术在1.57μm人眼安全OPO激光器中的应用

介绍了棱镜腔技术在1.57μm人眼安全OPO激光器中应用的理论基础、技术方案和实验结果,为高可靠性OPO激光器的研究提供了一种新的思路和方法。通过对角锥腔本征模式的讨论,发现了腔内的偏振特性满足OPO相位匹配条件,获得了内腔式OPO激光器稳定运转;通过对角锥腔退偏输出性能的分析,研究了角锥腔电光调Q外腔式OPO激光器;介绍了正交波罗棱镜腔OPO激光器。研究结果表明,采用棱镜腔技术的OPO激光器是获得高稳定性1.57μm人眼安全激光输出的有效新途径。

加固型人眼安全OPO激光器的设计

考虑到军用激光器对可靠性的特殊要求 ,设计了一种加固型的内腔式人眼安全OPO激光器。采用双定向棱镜折叠谐振腔、Cr4+ ∶YAG被动调Q晶体、Ce Nd∶YAG激光棒、非临界相位匹配KTP光参量振荡晶体 ,获得5 .3mJ/pulse 1 .5 7μmOPO激光输出 ,脉冲宽度约为 6ns,发散角约为 5mrad ,重复频率为 3Hz ,连续工作时间为1min ,且输出能量和光轴指向稳定的结果。该激光器具有结构紧凑、可靠性高的特点。

利用OPO的CARS光谱测温及狭缝函数的影响

论述了在宽带相干反斯托克斯拉曼散射(CARS)光谱技术中,利用光参量振荡器(OPO)替代常用的染料激光器作为斯托克斯光源的可行性,分析了OPO-CARS测温范围和仪器狭缝函数对测温结果的影响。理论分析和实验结果表明:测温范围在2200K以下,在CARS光谱测温技术中可以采用OPO替代染料激光器作为斯托克斯光源;狭缝函数对测量结果的影响是不容忽视的,相对比较来看,采用佛克脱函数形式最好。

Nd^(3+):YAG固体激光器泵浦的KTP-OPO实验研究

利用电光调Q脉冲Nd3+∶YAG固体激光器的532nm绿光作为抽运光源,以Ⅱ类相位匹配(θ=90°,φ=0°)、尺寸7mm×7mm×20mm的KTP晶体为参振晶体,构建了光参量振荡器实验系统.系统将入射抽运光振荡产生1 215nm的参量光及946nm的信号光,结果显示:最高耦合输出为12.14mJ,抽运光能量与参量光能量的最高转换效率为10.82%.

光参量振荡器(OPO)在主动红外化学毒剂遥测中的研究进展

光参量振荡器(OPO)连续的调谐能力以及固体激光器在军事应用中的诸多优点 ,使OPO技术在主动红外化学毒剂遥测的应用研究近年来成为十分活跃的领域之一。在 8～ 1 2 μm的红外光谱区目前已发展了几种连续可调谐的OPO激光系统 ,能量输出在 1mJ/脉冲水平的实验样机已经实现。为了达到探测距离为 1～ 3km ,化学毒剂激光遥测系统必需具有足够的信噪比 ,即要求单脉冲的激光能量应提高到 2～1 0mJ/脉冲或更高。发展的趋势是研制新型的OPO晶体材料 ,降低非线性晶体的激发阈值 ,提高损伤阈值以及将初始的光子撕开 ,以多光子的形式进入 8～1 2

KTP OPO产生2.7μm波段高峰值功率激光实验研究

通过1 064 nm激光泵浦KTP晶体光参量振荡(OPO)技术获得了高峰值功率2.7μm波段激光输出,对实验结果开展了详细的分析。泵浦源为电光调Q Nd:YAG激光器,光参量振荡器谐振腔采用单谐振结构,将两块相同的KTP晶体光轴相向放置以补偿走离效应,KTP晶体按?=0°,θ=62°切割以获得波长2.7μm波段激光输出,采用Ⅱ(B)类相位匹配(o→o+e)以利用较大的非线性系数。在泵浦能量为89 m J,脉宽10 ns的条件下,获得脉冲能量7.5 m J,波长2.67μm,脉宽8.5 ns的激光输出。

利用光学参量振荡器(OPO)测定KTP晶体折射率温度系数

文章提出了一种利用光学参量振荡器Optical Parametric Oscillator(OPO)测定KTP晶体折射率温度系数的实验方法。利用这种方法得到了KTP晶体折射率的温度系数。该方法具有操作简单、测量精度高和测量温度范围广等特点,并可用于其它多种非线性晶体折射率温度系数的测试。该系数对晶体的研究和晶体在非线性作用过程中的位相匹配有实际意义。

OPO—CARS测温技术的理论分析与实验研究

本文通过理论分析和实验结果，叙述了在宽带单脉冲反斯托克斯喇曼散射光谱（ＣＡＲＳ）法测温技术中，利用光参量振荡器（ＯＰＯ）代替以往常用的染料激光器作为斯托克斯光源的可行性问题。理论分析指出，测温范围在２２００Ｋ以内，采用ＯＰＯ作为斯托克斯光源是可行的，并利用该实验装置实测酒精灯火焰中的温度分布，其结果与辐射温度计测量结果比较的误差为４％以内。

Line-narrowed electro-optic periodically-poled-lithium-niobate Q-switched laser with intra-cavity optical parametric oscillation using a grazing-incidence grating

We report a line-narrowed electro-optic periodically-poled-lithium-niobate （PPLN） Q-switched laser with intra-cavity optical parametric oscillation using a grazing-incidence grating, producing 8-ns, 5-#J pulses at 10-kHz repetition rate when pumped with a 10-W diode laser at 808 rim. The output wavelength is centered at 1554.3 nm with a 0.03-nm spectral width. Wavelength tuning is achieved by rotating a mirror and changing the crystal temperature.

基于量子阻抗Lorentz振子的含芴二茂铁衍生物双、三光子吸收

文中基于量子阻抗洛伦兹振子(Quantum Impedance Lorentz Oscillator,QILO)模型,研究了含芴二茂铁衍生物的单、双、及三光子吸收特性。首先,理论推导并给出了用有效量子数、电子电量及质量和玻尔半径等微观量表示的该振子四、五阶非线性效应参量的计算参考公式。在此基础上,利用QILO模型,通过拟合取代基为R=NO_(2)的含芴二茂铁衍生物分子线性吸收光谱,得到了其在400 nm峰值附近的电子跃迁前后的有效量子数,并进一步推算了该分子的双、三光子吸收截面。数值计算结果显示:该化合物分子在793 nm波长附近的双光子吸收截面为0.49×10^(-20)cm^(4)⋅GW^(−1),在1260 nm和1314 nm附近的三光子吸收截面分别为2.01×10^(-25)cm^(6)⋅GW^(−2)、1.00×10^(-25)cm^(6)⋅GW^(−2),与实验结果均吻合较好。文中结果说明:QILO模型可以较好地描述以NO_(2)作为取代基的含芴二茂铁衍生物的单、双、及三光子的吸收特性。根据QILO模型的“依据介质的线性吸收光谱可以估算其多光子吸收截面”的特点,该模型或许能为寻找具有大的双、三光子吸收截面的材料提供一种可供参考的理论分析方法,降低研究多光子过程的综合实验成本。

中红外光学参量振荡器技术进展

35μm中红外激光器在环境污染检测、医疗、工业等领域具有重要的应用价值。本文总结了基于ZnGeP2、MgO∶PPLN晶体的光参量振荡器（OPO）的国内外发展现状,分析了其各自不同结构系统设计的优势和发展前景。指出高功率、小体积、轻重量的光学参量振荡器是未来重要发展方向,发展的技术核心是生长更大尺寸的中红外激光晶体以及研制更高性能指标的OPO泵浦源,并对中红外激光器的发展趋势进行了展望。

周期极化铌酸锂THz波产生理论分析

首先采用光参量振荡的机理研究了THz波在准相位匹配媒质周期极化铌酸锂晶体中同向传播与反向传播情况下 ,以及THz波从晶体表面辐射产生的特性 ;其次研究了THz波的温度调谐特性、极化反转光栅周期调谐以及改变入射泵浦光与光栅波矢夹角的调谐特性 ;然后分析了THz波谱宽特性 ,给出解析表达式 ,并与实验结果进行了比较 ,证明理论分析结果与Y .S .Lee等人所给出的实验结果符合很好 ;最后分析了THz波的稳定性与温度、光栅周期。