立方棱镜二向色分光膜消倍频反射峰的设计

立方棱镜二向色分光镜是实现多光谱共光路的重要器件.立方棱镜二向色分光镜因偏振效应而在高级次倍频处出现高反射峰,严重影响了短波区的透过率.利用虚设层概念,设计出了400 nm～900 nm波段高透过、1 064 nm激光波段高反射的立方棱镜二向色分光镜.给出了消除倍频反射峰的有效方法,并成功制作出光学性能优良的样品.采用这种设计方法获得的膜系结构简单,膜层数量少,材料选择广泛,对工艺要求简单,便于工艺实现,可重复性好.     

晶体X射线劳厄衍射分束特性研究

本文基于X射线衍射动力学分析了劳厄晶体的分束特性,模拟了晶体吸收和入射光角发散对于透射光和衍射光摇摆曲线的影响,定量给出晶体衍射面内角调节范围和晶体加工厚度对于劳厄衍射分束比的调制.在实验中,采用分析晶体和分束晶体的消色散配置限制入射光角发散的影响,实现300μm厚Si(220)晶体面内角调节劳厄衍射分束的精确测量,并得到300μm, 400μm和500μm厚度Si晶体分束比的调节范围,实现了透射光和衍射光强度的定量调制.     

单纤光纤探针测量空泡份额的实验研究

1前言气（汽）液两相流广泛应用于工业过程中。空泡份额是气（汽）液两相流的重要参数，它与流场、压力、热流密度和流型等密切相关。由于目前的理论计算模型还有较大的局限性，因此实验测量是研究气（汽）液两相流空泡份额的最主要的研究手段。经过近几十年的研究，各国学者开发出了许多有价值的空泡份额测量方法，其中包括平均空泡份额测量方法和局部空泡份额测量方法，这些测量方法本身各有各的局限性和一定的针对性。本文研究水平管束间汽液两相流流动和沸腾传热特性，流道中加热管柬的存在对流体流动产生强烈的影响，使管束间汽液两相…     

结构选择优化及过正量膜厚控制在激光析光膜中的应用

分忻了膜系设计中的膜层结构选择性优化方法,阐述了用光电极值法控制非λ／4膜系的膜厚的方法计算出沉积每一层县有极值的波长,然后根据此波长,给出一定的过正量进行膜厚模拟,最后确定每‘层的监控波长。利用这种方法可以提高膜系厚度的控制精度。该义介绍了自主开发膜系设计软件的部分功能,并利用该软件设计并镀制出1060nm的激光析光膜。     

Beam-splitting ratio impact on the SNR for the balanced heterodyne

Considered the beam-splitting ratio, the mathematical model of balanced heterodyne receiver is established, and the mathematical expression of the relationship between the signal-to-noise ratio and the beam-splitting ratio is obtained. Based on the experiment, we got the best range of beam-splitting ratio which is 0.159–0.5. The experiment results show that, in the framework of the best beam-splitting ratio, the balanced heterodyne receiver has better signal-to-noise ratio than the common heterodyne receiver.     

Utility transforms of optical fields employing deformable mirror

Diffraction optical devices of modest degrees of freedom (DOF), such as deformable mirrors, have not been exploited as general-purpose transformers of optical fields. Described in this Letter is a method that guides deformable mirrors to optimal surfaces allowed by the DOF for various desirable outcomes. The method is based on a modal optimization procedure with the help of Walsh functions in controlling the variables of the mirrors, i.e. the actuators. It is shown that a deformable mirror of modest DOF can provide field transformations for arbitrary beam-splitting, formation of ring-shaped beams, and coherent beam combining.     

Analysis of cylindrical microlenses simultaneously implementing beam-splitting and focusing based on rigorous electromagnetic theory

A cylindrical microlens for implementing both functions of beam-splitting and focusing on the preset positions is proposed. Phase functions of the microlenses are determined by the ray-tracing method. The performance of the microlenses is investigated based on rigorous electromagnetic theory and the boundary element method. Numerical results show that the designed microlenses basically can realize beam-splitting and focusing on the preassigned positions simultaneously. Dual and triple beam-splitting and focusing on the expected positions by the designed microlenses are demonstrated. Diffraction efficiency of the the beam-splitting and focusing is evaluated.     

Optimized design of parallel beam-splitting prism

A large lateral shearing distance of parallel beam-splitting prism is often needed in laser modulation and polarization interference. In this letter, we present an optimized design of parallel beam-splitting prism and list some different cases in detail. The optimized design widens the use range of parallel beam-splitting prism. At the wavelength of 632.8 nm, the law that the enlargement ratio changes with the refractive index and the apex angle is verified.     

多波段空间推扫相机光学系统设计

空间推扫相机的光学系统要求具有大视场、大口径、低F数等特点，据此设计了一种3波段光学系统。在参考国内外各种扫描或推扫相机结构的基础上，根据像差理论和系统要求，采用有效的分光方式和紧凑的光路结构，对不同的波段采用不同的像差校正方法，以及对系统优化组合后，最终得到了一个实用的光学系统。该系统包括可见、中波红外和长波红外波段，视场达到2.93°×0.3°，可见波段的F数为3.8，中波和长波波段的F数为1.9。从设计结果可以看出，系统3个波段的光学调制传递函数（MTF）都接近衍射极限。     

Y型光波导分束比和插入损耗测量技术研究

Y波导在集成光学系统中得到了广泛的应用,并拥有很大的潜力,近年来备受关注。因此了解它的各项指标至关重要。在Y波导的诸多指标中,分束比和插入损耗是2个重要指标。着重介绍了2个指标的测量装置及测量方法。对于分束比,分别采用波长为1300nm和1550nm的激光光源测量Y波导两尾纤的输出光功率。根据公式计算出分束比后,分析影响测量结果的主要因素,进行测量不确定度评定。对于插入损耗,主要是按照测量原理搭建测量装置,从理论上分析影响插入损耗测量的因素。通过对Y波导2个指标的测量,有助于更好地了解Y波导的性能。     

Silicon-based transmissive diffractive optical element

A silicon nitride (SiNx) membrane diffractive optical element (DOE) designed to exhibit beam-splitting and focusing behavior at visible wavelengths has been fabricated and tested. Since the fabrication process is based on silicon micromachining technology, the DOE is easily integrated with a laser diode chip and a photodiode chip on a silicon substrate to function as the hologram-laser-photodiode unit for use in the pickup head of a CD or DVD system. The SiNx film is deposited with low-pressure chemical-vapor deposition and the free-standing membrane is formed by KOH etching. The transmissive DOE showed a high diffraction efficiency (>20% for a binary-phase-level element). The experimental evaluation was in good agreement with the designed and modeled predictions.     

多功能鼠标光路的设计与分析

多功能无线光电鼠标运用2个图像摄影芯片,通过轨迹球滚动和鼠标座身移动两种方式实现光标移动。通过比较原始鼠标光路中2个图像摄影芯片能够接收到的最小光通量百分比,选择ADNS7530作为鼠标中唯一保留的图像摄影芯片。保持轨迹球光路不变,鼠标座光路中增加一个与轨迹球光路相同的LED光源。比较鼠标座的桌面反射光分别通过轨迹球反射、棱镜反射和平面镜反射后,最终到达图像摄影芯片的光通量百分比。确定并验证了鼠标座光路采用平面反射镜的设计方案,实现了无线空中操作鼠标轨迹球光路和鼠标座光路共用1个图像摄影芯片的目的。     

冰洲石-玻璃组合平行分束偏光镜的设计研究

为了既节省稀有昂贵的冰洲石晶体材料，又实现偏振光的大剪切差输出，采用冰洲石晶体与光学玻璃组合的方法，设计了一种新型平行分束偏光镜。该棱镜的前后半块分别为ZBaF₃玻璃和冰洲石晶体，由大折射率液态胶合剂溴代萘胶合而成。实验测试表明：该棱镜透射的2束平行光的消光比，o光可达10^－5；尽管受到光学玻璃的影响，e光的消光比仍优于10^－3；透射比均与纯冰洲石晶体材料的棱镜基本相当。理论分析表明：该棱镜自身结构带来的性能影响在一定情况下完全可以忽略，因此具有较好的应用前景。     

球透镜的衍射焦斑强度分布研究

根据国内外光通信耦合器件发展的趋势,研制了一种新型玻璃,依靠液体表面张力的作用,首次采用槽沉法来制备球透镜,得到了理想的效果。通过对直径为0.8mm的球透镜的焦斑强度分布进行研究,结果表明:当通光孔径分别为0.2mm,0.4mm和0.8mm时,球透镜的衍射焦斑强度的分布分别为0.2μm,0.4μm和1.0μm。因此,伴随着通光孔径的增加,球透镜的衍射焦斑强度分布增大,衍射的强度减小。     

双折射晶体在偏振光杨氏干涉实验中的应用

在正交偏光系统中置入一天然解理的双折射晶块和会聚透镜,可获得清晰的偏振光干涉分布图样。该文利用双折射晶体的偏振分束原理对干涉图样的产生和条纹分布进行具体的分析和计算。     

基于粒子群优化算法的膜系设计方法

粒子群优化算法是一种新的演化计算技术,与遗传算法相比,粒子群优化算法具有易于实现,控制参量少等优点,且在大多数的情况下,可快速收敛于最优解.为了获得更优的膜系结构,本文提出了一种利用粒子群优化算法进行膜系设计的方法,并以增透膜、高反膜及分光膜为优化设计实例验证该方法的可行性.在这些实例中,以理论反射率和实际反射率的误差平方和为评价函数.结果表明,将粒子群优化算法用于膜系设计是有效的,在相同设计条件下,应用粒子群优化算法可以得到比遗传算法更优的膜系结构.     

基于频域近红外光谱法的生物组织光学参数的检测与三维重构

生物组织的光学特性参数与组织的各种生理、生化以及病理过程密切相关。光学特性参数的检测与三维重构可以在一定程度上了解组织的内部结构及特性。基于频域近红外光谱法,使用美国ISS公司的频域近红外光谱检测系统,采用多光源多检测器技术,将830 nm的激光经过调制后,照射进放置了具有一定吸收系数和散射系数的异质体小球的牛奶中,检测出射光的光强和相位,然后应用光学扩散层析成像技术,通过计算含有异质体小球的牛奶的光学参数,重构出了牛奶中异质体的具体位置。实验结果表明,利用频域近红外光谱法得到的出射光的光强和相位信息,能够较准确地计算出牛奶及异质体小球的吸收系数和散射系数等组织光学参数,并可进一步定位出牛奶中异质体小球的位置。因此,可以考虑将该方法应用在分析及定位水果病变等农产品品质检测领域。     

Boundary-value problems in near-field optical microscopy and optical size resonances

We have solved a boundary-value problem for a ball probe interacting with a flat dielectric surface in an external optical radiation field. This interaction gives rise to the optical size resonance at frequencies significantly different from the natural frequencies of two-level atoms both in the medium and in the probe with allowance for the local field corrections. These resonances depend significantly on the distance from the probe center to the surface, on the ball probe size, on the concentration of two-level atoms in the probe and in the medium, on the spectral line width, and on the atomic inversion. The field strengths inside and outside the ball probe and a semiinfinite dielectric medium have been calculated in the near-field and wave zones. It is shown that the proposed electrodynamic theory of optical near-field microscopy agrees with the results of experimental measurements.     

Observation of ionization in a crystal interferometer

We present a new interferometric setup where interference of a fast probe electron affects the ionization cross section of an atom. Interference is detected in the intensity of the inelastically scattered electrons at the Bragg scattering angle in transmission. The crystal serves both as a target for core ionization and as a beam-splitting and phase-shifting device.     

双偏光大分束角输出棱镜的设计方法

本文介绍了一种双偏光大分束角输出的晶体偏光棱镜的设计方法。作者从实用性和工艺可行性两个角度考虑，采用了单、双窗两种设计形式，并给出了相关数据和具体工艺要求。器件结构紧凑、消光比高、使用方便。