共查询到18条相似文献,搜索用时 234 毫秒
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采用中红外CO2激光差频产生太赫兹波是提高转换效率和输出功率的一种有效方法。根据差频过程中的三波互作用对AgGaS2晶体进行了理论分析,数值模拟了oeo类和oee类两种匹配条件下差频产生太赫兹波的角度调谐曲线,并计算了光波在晶体中的走离角和允许参量。另外,还考虑了晶体的有效非线性系数和理论功率转换效率。研究结果表明,AgGaS2晶体适用于中红外CO2激光差频产生可广泛调谐的太赫兹波。 相似文献
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为了发展基于参量上转换的红外成像技术,依据可将10.6 μm红外辐射转换至可见波段的上转换器的理论模型,计算模拟了GaSe、ZnGeP2和AgGaS2晶体在各种相位匹配方式下的相位匹配角、走离角、和频允许角和有效非线性系数,并对结果进行了分析和对比.ZnGeP2晶体和AgGaS2晶体均可以实现非临界相位匹配,和频允许角... 相似文献
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为进一步发挥CO2激光差频产生太赫兹(THz)辐射的潜力,通过计算GaAs, ZnGeP2和GaSe晶体差频的相位匹配参数,结合晶体光学参数和损伤阈值比较3种晶体的差频性能和各自优势,分析相位失配和晶体吸收对差频转换效率的影响,得到3种晶体差频产生THz辐射各自的调谐范围、差频效率和实验操作等特征,表明选择低吸收系数晶体的重要性。 相似文献
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GaSe晶体的CO2激光倍频及其色散特性研究 总被引:1,自引:1,他引:0
为了研究GaSe晶体的倍频(SHG)及色散性质,采用声光调Q可调谐线偏振CO2脉冲激光器,在250 Hz重频脉冲下以共线oo-e相位匹配方式作用于GaSe晶体,得到CO2激光的可调谐SHG输出。测量了基频波长为9.3、9.6、10.3和10.6μm时的相位匹配角,并通过对比现有文献中色散方程的相位匹配角计算结果和测量结果,确定出最适用于GaSe晶体的色散方程。实验对SHG信号与晶体中光束方位角φ的关系进行测量。本文实验可以作为间接测量晶体色散关系的方法,为GaSe晶体的进一步研究打下基础;同时也可为其它非线性晶体的研究提供参考。 相似文献
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LiNbO3晶体的太赫兹参量振荡器设计 总被引:1,自引:1,他引:0
采用参量振荡方法实现太赫兹辐射(THz-wave Parametric Oscillator,TPO),因只需一个固定波长的泵浦源和一块非线性晶体,且具有非线性转换效率高、调谐简单而倍受瞩目.以LiNbO3晶体为例,采用Q调制的Nd:YAG激光器(1.064μm)为泵浦源,角度匹配的非共线相位匹配方式,设计了太赫兹参量振荡器,实现了当入射角α从8.2°变化到14°,相位匹配角θ相应地从16.2°变化到54.75°,太赫兹波与泵浦光之间的夹角β从8.84°~67.88°,闲频光从1.068μm变化到1.079 6μm,太赫兹波从284~74μm(1~4 THz)的连续太赫兹波振荡. 相似文献
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基于非线性光学差频及参量效应的太赫兹源 总被引:1,自引:1,他引:0
基于非线性光学技术的THz源具有其独特的性能和优点,将基于非线性光学差频原理和光学参量效应,从理论上研究并分析THz波与抽运光、闲频光及相位匹配角之间的关系,得到THz波输出的条件和范围,并设计出宽波段连续可调的THz源。以调QNd∶YAG激光器和光学参量振荡器(OPO)作为抽运源,以GaSe和MgO∶LiNbO3晶体作为差频非线性晶体,根据相位匹配理论及光学参量效应,搭建两套THz波产生系统。其中,基于光学参量效应的THz辐射源有效地产生出THz信号。 相似文献
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We have investigated the characteristics of a terahertz (THz) beam steering method based on a combination of difference-frequency
generation (DFG) with the principle of the phased array antenna. In the DFG of THz radiation from a nonlinear optical crystal
pumped by optical beams, the phase front of the THz radiation is indirectly tilted by adjusting the relative incidence angle
between the pump beams to the crystal. A magnification of the steering angle with a factor of 193 is demonstrated as the most
important effect provided by the method. The effect allows the use of a high-speed optical deflector for adjusting the incidence
angle, accelerating the steering more than a hundred times compared with mechanical methods. The phase mismatching between
the THz radiation and the pump beams as well as the refraction at the crystal surface limit the steering angle of the THz
radiation to 56°, full width at half maximum. 相似文献
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1.双轴晶体KTiOPO_4(KTP)由于其优良的非线性光学性能而受到普遍重视,但一般仅限于在一个通光方向上获得一种非线性光学过程。考虑到双 相似文献
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Raju Sinha Mustafa Karabiyik Arash Ahmadivand Chowdhury Al-Amin Phani Kiran Vabbina Michael Shur Nezih Pala 《Journal of Infrared, Millimeter and Terahertz Waves》2016,37(3):230-242
We propose and investigate in detail a novel tunable, compact, room temperature terahertz (THz) emitter using individual microdisk resonators for both optical and THz waves with the capability of radiating THz field in 0.5–10 THz range with tuning frequency resolution of 0.05 THz. Enhanced THz generation is achieved by employing a nonlinear optical disk resonator with a high value of second-order nonlinearity (χ (2)) in order to facilitate the difference-frequency generation (DFG) via nonlinear mixing with the choice of two appropriate input infrared optical waves. Efficient coupling of infrared waves from bus to the nonlinear disk is ensured by satisfying critical coupling condition. Phase matching condition for efficient DFG process is also met by employing modal phase matching technique. Our simulations show that THz output power can be reached up to milliwatt (mW) level with high optical to THz conversion efficiency. The proposed source is Silicon on Insulator (SoI) technology compatible enabling the monolithic integration with Si complementary metal-oxide-semiconductor (CMOS) electronics including plasmonic THz detectors. 相似文献
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Hirohisa Uchida Kengo Oota Koutarou Okimura Kodo Kawase Kei Takeya 《Journal of Infrared, Millimeter and Terahertz Waves》2018,39(6):509-513
OH1 crystal is an organic nonlinear optical crystal with a large nonlinear optical constant. However, it has dispersion of refractive indices in the terahertz (THz) frequency. This limits the frequencies that satisfy the phase matching conditions for THz wave generation. In this study, we addressed the phase matching conditions for THz wave generation by combining an OH1 crystal with prism-coupled Cherenkov phase matching. We observed the generation of single-cycle THz pulses with a spectrum covering a frequency range of 3 THz. These results prove that combining prism-coupled Cherenkov phase matching with nonlinear optical crystals yields a THz wave generation method that is insusceptible to crystal dispersion. 相似文献
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给出了ZnTe电光晶体折射率和吸收系数随太赫兹波频率而变化的计算曲线,比较了太赫兹波在ZnTe中传播时的相速度和群速度。通过与太赫兹频率和晶体厚度相关的电光效率响应函数,理论计算了ZnTe电光晶体对太赫兹脉冲的探测电光响应,得到了晶体厚度与探测到的太赫兹频谱宽度的定性关系,从计算结果中找到了ZnTe电光晶体在5.3 THz和6.2 THz等多个频点的探测盲点,这些探测盲点来自于ZnTe电光晶体与相应频点太赫兹波的栅格共振吸收。结合自制的大口径太赫兹光导天线和1 kHz脉冲重复频率的太赫兹时域光谱实验系统,通过差分探测技术,从实验上得到了太赫兹波极化方向与〈110〉型ZnTe晶体晶轴方向的六个最佳匹配角度,给出了太赫兹电场最大值随晶轴与太赫兹波极化方向之间夹角变化的曲线及经验公式,这将有利于在实践中对该现象的深入理解和对探测灵敏度的有效提高。 相似文献