Red Laser-Induced Domain Inversion in MgO-Doped Lithium Niobate Crystals

A laser beam at wavelength 647nm is focused on a sample of 5mol% MgO-doped lithium niobate crystal for domain inversion by a conventional external electric field. In this case, a reduction of 36% in the electric field required for domain nucleation （nucleation field） is observed. To the best of our knowledge, it is the longest wavelength reported for laser-induced domain inversion. This extends the spectrum of laser inducing, and the experimental results are helpful to understand the nucleation dynamics under laser illumination. The dependence of nucleation fields on intensities of laser beams is analysed in experiments.     

红外线演示实验的再改进

本刊第14卷第4期发表的《实验改进二则》一文中关于红外线反射演示实验仍有两点不妥，讨论如下．原文实验装置如图1，“使铁球位于凹面镜的焦点附近，用烧瓶接收红外线，可以看到红墨水柱沿型管（向外）移动（瓶内空气受热膨胀）．如果取走四面镜，则红墨水柱停止移动（或移动速度十分显著的缓慢）．”以出来说明红外线跟可见光一样是能够被反射的证据明显不够充足．1．虽然铁球放置在四面镜的焦点附近，但由于铁球直径较大（直径为3—5cm，不像光学中的点光源），到达烧瓶的红外线不能理解为全部是来自于四面镜反射的红外线．实际上烧瓶接…     

Chemical Synthesis and Characterization of Flaky h-BCN at High Pressure and High Temperature

Hexagonal boron carbonitrogen （h-BCN） compound is synthesized from a mixture of boron powder and CNH compound prepared by pyrolysis of melamine （CaH6N6） under high temperature （1400-1500℃） and high pressure （5.0-5.5 GPa）. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Raman spec- troscopy are used to determine the chemical composition and bonds of the product. The results show that the product has composition of B0.18C0.64N0.16 （near BC4N） and atomic-level hybrid. X-ray diffraction analysis indicates that the powder has a hexagonal network structure. Scanning and transmission electron microscopy results suggest that h-BCN compound morphology is mainly flaky in width about 1 μm and thickness 200nm.     

Ultraviolet and visible upconversion dynamics in Er^3＋：YAlO3 under ^2H11/2 excitation

The luminescence of Er^3＋：YAlO3 in ultraviolet visible and infrared ranges under the 518 nm excitation of the multiples ^2H11/2 have been investigated. Ultraviolet （275 nm and 318 nm）, violet （405 nm and 413 nm） and blue （474 nm） upconversion and infrared downconversion luminescence has been observed. By means of measuring the fluorescence decay curves and using the theory of rate equations, the luminescence kinetics was studied in detail and the processes of energy transfer upconversion （ETU） and excitation state absorption （ESA） were proposed to explain the upconversion phenomena.     

Design of Infrared Inverted Telephoto-Optical System with Double-Layer Harmonic Diffractive Element

A double-layer harmonic diffractive element （HDE） structure is investigated and the optimization procedure is given based on the equation of diffraction efficiency of the double-layer diffractive optical element. A new infrared double-layer inverted telephoto-optical system with an HDE is designed, which can work in the mid- and farinfrared wavebands. The diffraction efficiency of the system at each wavelength in the designed two wavebands is larger than 90%, which improves the image contrast and the imaging quality significantly.     

Broadband Infrared Luminescence of Ni^2＋ in Petalite-Type Transparent Glass Ceramics

Transparent Ni^2＋-doped magnesium aluminosilicate glass ceramics are prepared. The formation of petalite-type crystallites in the glass ceramics is confirmed by x-ray diffraction. Broadband infrared luminescence centred at around 1235nm with full width at half maximum （FWHM） of about 300nm is observed from the Ni^2＋-doped glass ceramics. The observed infrared emission could be attributed to the ^3T2（F） → ^3A2（F） transition of octahedral Ni^2＋ ions in petalite-type crystallites. Theproduct of the fluorescence lifetime and the stimulated emission cross sections is 1.2 ×10-24 cm^2s.     

Near Infrared Photoluminescence from Yb,Al Co-implanted SiO2 Films on Silicon

Intense room-temperature near infrared （NIR） photoluminescence （980 nm and 1032 nm） is observed from Yb,Al co-implanted SiO2 films on silicon. The optical transitions occur between the ^2F5/2 and ^2F7/2 levels of Yb^3＋ in SiO2. The additional Al-implantation into SiO2 films can effectively improve the concentration quenching effect of Yb^3＋ in SiO2. Photoluminescence excitation spectroscopy shows that the NIR photoluminescence is due to the non-radiative energy transfer from Al-implantation-induced non-bridging oxygen hole defects in SiO2 to Yb^3＋ in the Yb-related luminescent complexes. It is believed that the defect-mediated luminescence of rare-earth ions in SiO2 is very effective.     

Near Infrared Broadband Emission from Bismuth-Dysprosium Codoped Chalcohalide Glasses

We investigate the broadband infrared emission of bismuth doped and bismuth/dysprosium codoped chalcohalide glasses. It is found that the bismuth/dysprosium codoping can drastically enhance the f/uorescence as compared with either bismuth or dysprosium doped glasses. Meanwhile, the full width at half maximum of bismuth/dysprosium codoped glasses is over 170 nm, which is the largest value among all the reported rare-earth doped chalcohalide g/asses. An ideal way for energy consumption between bismuth and dysprosium ions is supposed. Such improved gain spectra of both bismuth and dysprosium ions may have potential applications in developing broadband fibre amplifiers.     

红外测温原理实验

采有经计量校准作为已知温度特性的辐射体，再用其已知特性校准相同辐射体的温度，并用微机对实验数据作回归分析，将难度较大的实验简化成基础物理综合实验，这种“替代校准法”可避开“比辐射率修正”的困难。     

Detection Wavelength of Strained InxGa1-x As/GaAs Very-Long-Wavelength Quantum Well Infrared Photodetectors

Detection wavelength is one of the key performance indices of infrared photodetectors. We study the character of detection wavelength of the strained InxGa1-xAs/GaAs very-long-wavelength （〉 12 μm） quantum well infrared photodetectors （VLW-QWIPs） characterized by the photoluminescence （PL） and photocurrent （PC） measurements. Based on the theoretical calculation and experimental data, we have built a practical model for the Inx Ga1-xAs/GaAs strained VLW-QWIPs, from which the interband transitions, intersubband transition and peak detection wavelength can be determined. Afterwards, the dependences of detection wavelength and device operation mode on the In mole fraction and InxGa1-xAs well width are presented, which will be helpful for device design and optimization.     

脉搏波光电传感器

根据人体工程学、手指的解剖结构和红外线透射原理研制了人体脉搏波光电传感器.其关键在于符合人体工程学的非接触式微功率光电传感器设计,使得人体组织尤其是穴位部分始终保持自然放松状态,确保测试结果不会因自身神经紧张和意外的外界条件变化而发生扭曲.该传感器使用了标准USB1.0接口,从而简化了电路设计.     

Perturbation study via rotational-resolved spectrum in the triplet band d3Δ-a3∏(2, 1) of CO

The triplet band d³Δ-a³∏ (2, 1) of the CO molecule in the near infrared region of 12350--12850cm^-1 has been observed and analysed by taking into account the perturbation interaction between the d³Δ(v = 2) and a³∏ (v = 9) states. The most perturbed lines and most precise perturbation parameters, \alpha₂ and \beta₂, and electronic perturbation constants,\xi _\e and \eta _\e , for the d³Δ (v= 2) and ³∏ (v = 9) states have been obtained.     

红外技术的物理基础及其军事应用

本文介绍了红外技术的物理基础及其在军事领域的主要应用 .     

红外气体浓度测试仪设计

在实验室条件下采用红外光谱对气体浓度进行定量分析的技术已很成熟,但是,适用野外环境条件下进行气体浓度精密测量的仪器并不多见。本文设计的仪器是文献〔３〕所述的一种便携式红外气体浓度测试仪器的改型,测量范围０－１００％,精度比文献〔３〕所述红外气体浓度测试仪器有所提高,且使用方便,工作稳定,数据可靠。     

一种基于遗传算法的红外无损检测缺陷的新方法

红外无损检测的本质可归为热传导反问题的求解。利用通过解析法求解热传导正问题得出的结论，提出基于遗传算法优化求解的红外无损检测缺陷信息新方法，该算法采用浮点数编码，并采用多遗传算子并行损作，不仅获得了好的结果，而且维系了种群的多样性。模拟实验验证了算法的鲁棒性和可靠性。     

红外技术的物理基础及其军事应用

本文介绍了红外技术的物理基础及其在军事领域的主要应用。     

1-W, high-repetition-rate room temperature operation of mid-infrared optical parametric oscillator based on periodically poled MgO-doped LiNbO

In this paper a high-repetition-rate mid-infrared （mid-IR） optical parametric oscillator based on periodically poled MgO-doped LiNbO3 （PPMgLN） at room temperature was demonstrated. The maximum average mid-IR output power at 3.63μm was 1.02 W with the repetition rate of 60kHz and corresponding efficiency from the pump to the idler was 26.7%. The temperature tuning and the period tuning characteristics were also discussed.     

Optimized Optomechanical Micro-Cantilever Array for Uncooled Infrared Imaging

We present a new substrate-free bimaterial cantilever array made of SiN_x and Au for an uncooled micro-optomechanical infrared imaging device. Each cantilever element has an optimized deformation magnification structure. A160×160 array with a 120μm×120μm pitch is fabricated and an optical readout is used to collectively measure deflections of all microcantilevers in the array. Thermal images of room-temperature objects with higher spatial resolution have been obtained and the noise-equivalent temperature difference of the fabricated focal plane arrays is given statistically and is measured to be about 270mK.