TDI CCD立体相机内方位元素测试技术研究

依据星载单镜头TDICCD立体相机立体成像及测绘要求,结合普通测绘相机内方位元素,提出了星载单镜头立体相机内方位元素由焦距、主点位置、立体成像角(前后视交角)、图像畸变等元素组成。给出了立体相机内方位元素测试的方法,针对立体相机成像特点给出了计算内方位元素的算法,对其进行了实际测量和验证,其测量结果符合设计要求。     

Pupil design based on Fisher information optimization to extend field depth in practical optical system

<正>Wavefront coding(WFC) is used to extend the field depth of an incoherent optical system by employing a phase mask on the pupil.We uses a Fisher information(FI) metric based optimization method to design a phase mask by taking the modulation transfer function(MTF) of the practical optical system into consideration. This method can modulate the wavefront so that the point spread function and optical transfer function are insensitive to the object distance.The simulation results show that the optimized phase mask based on the proposed method can further improve the defocusing image quality while maintaining the focusing image quality.     

Two Kinds of Cavity Geometry for Enhanced Laser Cooling of Solids

We present a comparison between intracavity cooling and external cavity cooling for optical refrigeration. The results show that the intracavity scheme is preferred at low optical densities （〈 0.008）, while the external cavity scheme is preferred at higher optical densities （〉 0.01）. We can choose the proper scheme for different eases in experiments. Moreover, under the same conditions, taking Yb^3＋-doped ZBLAN （ZrF4-BaF2-LaF3-AlFa-NaF） film as an example, the cooling processes of the two scheme are obtained. The calculated results show that intracavity cooling will achieve a larger temperature drop for a thin film sample. Finally, the diode laser may become a candidate for the intraeavity model briefly discussed.     

Adiabatic Passage Based on the Calcium Active Optical Clock

We propose a new application of the optical adiabatic passage effect for the excitation of a thermal atomic beam, which will be used in the calcium active optical clock to produce population inversion. A comparison between the optical adiabatic passage effect and the Rabi π pulse is investigated, 99% of the calcium atoms in the atomic beam that has a wide velocity distribution will be excited to the upper state for population inversion using the adiabatic passage, while 76% at most will be excited to the excited state using the π pulse with suitable parameters.     

Photonic Band Gap Properties of Three-Dimensional SiO2 Photonic Crystals

Three-dimensional SiO2 photonic crystals （PhCs） are fabricated on quartz substrates by the vertical deposition method. Scanning electron microscopy measurement reveals that the samples exhibit an ordered close-packed arrangement of SiO2 spheres. It is found that the position of the [111] photonie band gap （PBG） shifts to a long wavelength （red shift） with increasing sphere size. Gap broadening effects are observed due to the presence of defects in the samples. Moreover, the optical properties of the PBG are very sensitive to the annealing temperature. Our results indicate that the optical properties of the PBG can be easily tuned in the visible region by appropriate experimental parameters, which will be useful for practical applications of PhC optical devices.     

一种数字全息图零级项消除的新方法

针对离轴数字全息图中的零级项问题,提出用独立分量分析方法对零级项进行压缩.首先通过CCD获取同一物体的两幅干涉强度不同的全息图构成观测信号,然后采用独立分量分析方法(Independent Component Analysis(ICA))从观测信号中分离出零级项和共轭项,再从获得的共轭项中减去残余的零级项分量,实现零级项的有效压缩,并用模拟结果论证该方法在处理零级项压缩方面的优越性和有效性.     

Composition-Dependent Characterization of Sb2Te3 Thin Films Prepared by Ion Beam Sputtering Deposition

The optimization of ion beam sputtering deposition process for Sb2 Te3 thin films deposited on BK7 glass substrates is reported. The influence of composition ratio on the thermoelectric properties is investigated. X-ray diffraction shows that the major diffraction peaks of the films match with those of Sb2 Te3. Hall effect and Seebeck coefficient measurement reveal that all the samples are of p-type. The Sb2 Te3 thin films exhibit the Seebeck coefficient of 190μVk^-1 and the electrical conductivity of 1.1 × 10^3 Scm^-1 when the atomic ratio of Sb to Te is 0.65. Carrier concentration and motility of the films increase with the increasing atomic ratio of Sb to Te. The Sb2 Tea film with a maximum power factor of 2.26×10^-3 Win^-1K^-2 is achieved when annealed at 400℃. Raman measurement shows that the main peaks are at about 120 cm^-1, 252 cm^-1 and 450 cm^-1, in agreement with those of V-VI compound semiconductors.     

高速流场对光传输特性的影响

利用一座小型跨超声速风洞进行了高速流场光传输特性试验研究。光束在高速流场中传输时,由于流场密度变化,光波波前会发生畸变。利用风洞提供0.7,2.0和3.0等气流马赫数的流场条件,采用基于夏克-哈特曼波前传感器的光学测量系统,对光束在风洞流场中传输时的波前畸变进行了测量。试验结果表明:随着风洞流场马赫数增加,流场对光波传播的影响增大,光波波前畸变量显著提高。因此,在利用风洞进行气动光学试验研究之前,有必要消除风洞流场本身对光波传输的严重干扰。     

基于孔径分布概念的全景系统光学设计

为了改变坦克现有探测与观瞄系统低效、精确性不足等弱点,进行基于孔径分布概念的全景系统光学设计。原理是利用4个孔径大于90°的物镜对360°全景图像信息进行孔径分布实时采集,采集的四路图像通过内部转像系统的折转汇成一路,由一个CCD接收,提供准确和平整的全景图拼贴的图像,对系统理想情况下的发现和分清目标距离以及盲区范围进行估算,并通过光线追迹估算出系统失效探测距离。系统在57 m~6.45 km的工作距离内,实现全方位、实时性的观瞄与探测功能。     

液体表面波及其谐波的光衍射效应

为了探究液体表面波的波动规律,提出了一种基于激光衍射的探测方法.未扩束的激光束直接斜入射到波动液面,液面波动的强度由电磁式激发器控制、频率由信号发生器控制,用CCD采集光衍射图样并传送到计算机中实时处理.根据波动光学理论,给出了衍射光场和液体表面波之间的解析关系,发现实验现象和理论分析吻合.实验结果表明:该方法具有实时、准确、无损的特点.