窄带干涉滤光片抗击不同输出方式激光的损伤特性研究

利用Nd∶YAG调Q单脉冲激光和自由脉冲激光对硬膜窄带干涉滤光片进行激光损伤阈值的测试,并且采用表面热透镜技术测量了滤光片的吸收率。实验发现：窄带干涉滤光片的吸收率和激光损伤阈值强烈依赖于辐照激光波长与窄带干涉滤光片通带的相对位置;在调Q单脉冲激光作用下,不同中心波长的滤光片损伤形貌存在明显的差别,而在自由脉冲激光作用下,各滤光片的损伤形貌则趋于相同,均表现为典型的热熔烧蚀破坏。根据实验结果,结合损伤形貌,通过驻波场理论对激光作用下滤光片内电场分布的分析与模拟,探讨了两种激光模式作用下滤光片的损伤特征和损伤机理的不同特点。     

1064 nm窄带干涉滤光片激光破坏研究

干涉滤光片由于内部谐振场共振吸收特性,其激光破坏过程有别于全反膜而具有特殊的性质。本文从谐振场及湿度场理论出发,计算得出了ZnS/MgF2为主材料的滤光片的谐振场及温度场分布规律。在此规律指导下,对相同膜系结构的一系列滤光片的激光破坏阈值、吸收及破坏形貌进行了测量与分析,结合实验结果对干涉滤光片独具特色的破坏发展过程作出了描述,并给出了一定的解释。     

激光入射角对干涉带通滤光片输出性能的影响

利用红外光谱分析技术,研究了激光入射角度对干涉带通滤光片输出性能的影响。激光入射角的变化对滤光片的峰值波长、峰值透过率等性能参数具有明显的影响;分析了中红外滤光片对3.8μm波段激光的透射性能,给出了滤光片的输出特性与入射激光角度的变化关系。     

DWDM极窄带干涉滤光片的误差与自动补偿效应

针对现代光通信中的核心元件之一--密集型波分复用(DWDM)系统中极窄带光学薄膜干涉滤光片的指标要求,提出采用基于四分之一波长的规整膜系是实现密集型波分复用功能的最佳选择.对给定的设计方案的各个膜层的误差灵敏度分布、特定膜层的误差成因进行了分析,并对多个膜层进行了随机分布的误差模拟.通过对直接极值法监控中不同误差的补偿机理的研究,指出采用直接极值法监控是目前为止镀制这种滤光片的有效方法.最后讨论了可能存在的两种系统误差.     

双通偏振干涉滤光片的研究

研究了等厚度双通偏振干涉滤光片，在此基础上提出了新型双通偏振干涉滤光片，并分析了单通、双通以及新型双通偏振干涉滤光片的光谱特性。结果表明，新型双通偏振干涉滤光片不仅具有更好的光谱特性，而且能进一步减少延迟片数目，具有非常重要的实用价值，可望在基于硅片的液晶投影仪分/合色系统中得到广泛应用。     

单腔,双腔窄带干涉滤光片在单色光照射下的光散射

从理论和实验上讨论了单腔、双腔窄带干涉滤光片中的光散射现象，结果表明：光散射主要是由干涉滤不片和腔结构引起的。当波长小球滤光片峰值波长的激光束入射到该滤光片上时，在滤光片两侧形成散射光锥，散射光的散射角等于滤光片峰值紫移到入射光波长时滤光片所转过的角度，理论计算和实验结果符合得很好。     

全向激光告警系统中窄带滤光片的透射率分析

根据全向激光告警系统的结构特点,阐明了系统中大视场接收和窄带光谱滤波技术之间的矛盾.通过建立法布里-珀罗滤光片的模型,从反射膜的反射率、位相跃变以及间隔层介质所产生的光程差等因素,分析了激光从不同入射角入射时,滤光片具有不同的透射率.给出了激光入射角与透射率之间的关系公式,通过实验验证其有效性.     

连续激光辐照ZnSe/MgF2/K9滤光片的透射特性研究

 分析了连续激光辐照ZnSe/MgF₂/K9滤光片引起透射特性的变化。在室温条件下，用波长0.632 8μm激光作为探测光束，测量了1.06μm连续激光辐照ZnSe/MgF₂/K9滤光片温升引起薄膜折射率的改变，导致探测光束通过干涉滤光片后透过率的热致非线性变化。在光斑直径0.75mm条件下，测量了不同功率激光辐照ZnSe/MgF₂/K9滤光片引起温升随时间的变化。在激光功率30W，辐照时间2.52s条件下，实验观测到ZnSe/MgF₂/K9滤光片薄膜破坏温度约为90℃，辐照时间10s时干涉滤光片形成的薄膜龟裂形貌。     

连续激光辐照ZnSe/MgF2/K9滤光片的透射特性研究

分析了连续激光辐照ZnSe/MgF2/K9滤光片引起透射特性的变化。在室温条件下,用波长0.632 8μm激光作为探测光束,测量了1.06μm连续激光辐照ZnSe/MgF2/K9滤光片温升引起薄膜折射率的改变,导致探测光束通过干涉滤光片后透过率的热致非线性变化。在光斑直径0.75mm条件下,测量了不同功率激光辐照ZnSe/MgF2/K9滤光片引起温升随时间的变化。在激光功率30W,辐照时间2.52s条件下,实验观测到ZnSe/MgF2/K9滤光片薄膜破坏温度约为90℃,辐照时间10s时干涉滤光片形成的薄膜龟裂形貌。     

Q开关Nd:YAG脉冲激光对红外滤光片的损伤效应

 介绍了由滤光片膜层结构决定的激光在光学薄膜中形成温度场及驻波场特性。用1.06μm调Q Nd:YAG激光器，在激光脉冲宽度10ns和光斑直径0.61μm的条件下，进行了激光辐照红外滤光片的损伤特性实验研究。根据脉冲激光辐照红外滤光片后样品损伤分析，发现滤光片的最初损伤发生在里面的膜层中，从而在实验上验证了计算得到的滤光片膜层中存在其温度场及驻波场的结果。它对提高红外滤光片的抗激光辐照能力研究具有一定的参考价值。     

Laser-induced damage of Ta2O5/SiO2 narrow-band interference filters under different 1064 nm Nd:YAG laser modes

The laser-induced damage (LID) behavior of narrow-band interference filters was investigated with a Nd:YAG laser at 1064 nm under single-pulse mode and free-running mode. The absorption measurement of such coatings was performed with surface thermal lensing (STL) technique. The damage morphologies under the two different laser modes were also studied in detail. It was found that all the filters exhibited a pass-band-center-dependent absorption and laser-induced damage threshold (LIDT) behavior, but the damage morphologies were diverse. The explanation was given with the analysis of the electric field distribution and the operational behavior of the irradiation laser.     

Laser-induced damage of 1064-nm narrow-band interference filters under different laser modes

The laser-induced damage behavior of narrow-band interference filters was investigated with a Nd:YAG laser at 1064 nm under single-pulse mode and free-running laser mode.The absorption measurement of such coatings has been performed by surface thermal lensing(STL)technique.The relationship between damage morphology and absorption under the two different laser modes was studied in detail.The explanation was given by the standing-wave distribution theory.     

Laser-induced damage of 1064-nm narrow-band interference filters under different laser modes

The laser-induced damage behavior of narrow-band interference filters was investigated with a Nd:YAG laser at 1064 nm under single-pulse mode and free-running laser mode. The absorption measurement of such coatings has been performed by surface thermal lensing (STL) technique. The relationship between damage morphology and absorption under the two different laser modes was studied in detail. The explanation was given by the standing-wave distribution theory.     

Improved performance of InGaZnO thin-film transistors with Ta2O5/Al2O3 stack deposited using pulsed laser deposition

Ta₂O₅/Al₂O₃ stacked thin film was fabricated as the gate dielectric for low-voltage-driven amorphous indium–gallium–zinc-oxide (IGZO) thin film transistors (TFTs). The Ta₂O₅/Al₂O₃ stacked thin film exhibits a combination of the advantages of Al₂O₃ and Ta₂O₅. The IGZO TFT with Ta₂O₅/Al₂O₃ stack exhibits good performance with large saturation mobility of 26.66 cm² V⁻¹ s⁻¹, high on/off current ratio of 8 × 10⁷, and an ultra-small subthreshold swing (SS) of 78 mV/decade. Such small SS value is even comparable with that of submicrometer single-crystalline Si MOSFET.     

Laser Resistance of Ta2O5/SiO2 and ZrO2/SiO2 Optical Coatings under 2 9m Femtosecond Pulsed Irradiation

Ta2O5/SiO2 and ZrO2/SiO2 high reflecting （HR） coatings are prepared by ion beam sputtering and electron beam evaporation, respectively. The laser-induced damage thresholds （LIDTs） of these samples are investigated with 2μm femtosecond pulse lasers （80fs, 1kHz）. It is found that the Ta2O5/SiO2 HR coating has a higher capability of laser damage resistance than the ZrO2/SiO2 HR coating in the 2μm femtosecond regime. The scanning electron microscope results show that the damage sites of the ZrO2//SiO2 FIR coating have a relatively porous structure, the loose structure of coatings will provide more sites for water molecules, and the LIDTs of HR coatings will be reduced as a result of the strong water absorption at the wavelength of 2 μm.     

高重频CO_2激光干扰技术研究

本文针对高重频CO_2激光干扰技术展开分析和研究。首先,概述了激光对抗武器的概念、分类和特点,以及激光对抗武器的干扰与破坏的主要目标对象。其次,分析了红外探测器激光干扰损伤效果的检测方法。再次,分析了光学元件激光变形损伤效果的检测方法以及光学薄膜的激光损伤检测方法。按照上述检测方法进行实验,分别对红外单元探测器、光学元件、光学薄膜和其他材料的激光损伤阈值实验数据进行分析与讨论。最后,总结了全文并且展望了激光干扰技术的发展。     

Induced transmittance in alexandrite laser eye-protectors—a survey of different types of laser filters

Different types of eye-protection filters are examined with the emphasis being laid on the irradiation-dependent spectral transmittance. Most of the dyes used for polycarbonate laser filters show the effect of induced transmittance. This may be critical with respect to eye safety because these absorber types are frequently used in filters for protection against alexandrite laser irradiation.     

不同波长三倍频DKDP晶体的激光损伤

采用传统降温法,利用高纯原料从氘化程度为80%的溶液生长了四方相磷酸二氘钾（DKDP）晶体,并按Ⅱ类三倍频方式切割晶体。三倍频用DKDP晶体的最大问题在于其抗光伤阈值低于KDP晶体,严重限制了激光输出的能量密度和晶体使用寿命。考察了不同波长下三倍频DKDP晶体的损伤阈值,以及激光退火效应。实验表明,激光退火对于DKDP晶体的损伤阈值有显著的提升作用,基频、倍频、三倍频的提升效果分别达到1.4,1.9,2.7倍,是改善DKDP晶体抗光伤能力的有效途径。     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.