凹折射微透镜阵列的离子束刻蚀制作

利用光刻热熔成形工艺及离子束刻蚀制作 12 8× 12 8元凹微透镜阵列。所制硅及石英凹微透镜的典型基本图形分别为凹球冠形、凹柱形和矩顶凹面形。分析了在光致抗蚀剂柱凹微透镜图形制作过程中的膜系匹配特性 ,与制作该种微透镜有关的光掩模版的主要结构参数 ,以及光致抗蚀剂掩模工艺参数的控制依据等。探讨了在凹微透镜器件制作基础上利用成膜工艺开展平面折射微透镜器件制作的问题。采用扫描电子显微镜 (SEM)和表面轮廓仪测试了所制石英凹微透镜阵列的表面微结构形貌。给出了所制石英凹微透镜阵列远场光学特性的测试结果。     

Model analysis of effect of diffraction focus characteristics of microlens arrays on parallel laser direct writing quality

In order to study the effect of diffraction focusing characteristics of microlens arrays on the parallel laser direct writing quality, we use nonparaxial approximation to analyze the diffraction focus characteristic of a single microlens, take into consideration the cross-talk effect of a number of microlenses on the diffraction focusing characteristics of an array, and establish a theoretical focusing intensity model of a microlens array to describe the influence of a change in F-number and/or center distance on the diffraction focusing characteristics of a parallel laser direct writing system while incident writing laser is normal. Numerical simulation results indicate that there is a cross-talk effect among microlenses which increases as the F-number increases when the center distance is the same as the smaller aperture, and parallel writing quality can be improved by reducing or totally eliminating the cross-talk effect by reducing F-number and/or increasing center distance.     

基于微透镜阵列匀束的激光二极管面阵抽运耦合系统分析

为了提升高功率固体激光器中激光二极管(LD)面阵抽运场性能,采用几何光学和数理统计分析的方法,建立了基于微透镜阵列匀束的LD面阵抽运耦合系统的数学与物理模型,对微透镜阵列参数与最终耦合输出抽运场参数之间的关系进行分析,明确了微透镜单元F数、微透镜通光单元数以及微透镜阵列空间周期参数的设计原则.经实验测试,优化设计完成的LD面阵抽运耦合系统光场不均匀度为7.9%,耦合效率为90.7%.     

衍射微透镜列阵在Shack-Hartmann波前传感器中的应用

菲涅耳衍射微透镜列阵是目前广泛应用的衍射光学元件之一,它是基于衍射原理,由计算机设计,并通过微细加工技术制作成的.本文介绍了8相位台阶菲涅耳衍射微透镜列阵的制作方法,并描述了一个用16×16微透镜列阵形成的小型 Shack-Hartmann 波前传感实验系统,用该系统可对入射波前进行测量和重建.     

High-resolution beam steering using microlens arrays

Imaging or beam-steering systems employing a periodic array of microlenses or micromirrors suffer from diffraction problems resulting from the destructive interference of the beam segments produced by the array. Simple formulas are derived for beam steering with segmented apertures that do not suffer from diffraction problems because of the introduction of a moving linear phase shifter such as a prescan lens before the periodic structure. The technique substantially increases the resolution of imaging systems that employ microlens arrays or micromirror arrays. Theoretical, numerical, and experimental results demonstrating the high-resolution imaging concept using microlens arrays are presented.     

Multiple-spot optical tweezers created with microlens arrays fabricated by proton beam writing

We report two different applications for using arrays of microlenses on glass substrate to facilitate multiple-spot optical trapping of colloidal microbeads. The array of microlenses was made of SU8 or PMMA resist and created by a combination of Proton-Beam writing followed by thermal reflow processes. Firstly, similar to previous reports [8, 9, 10 ], the lenses were utilized as an optical element in generating multiple laser spot arrays that were subsequently focused down to impose a microbead array. In addition, we demonstrated the feasibility of a novel approach of integrating the microlens array into a sample chamber to provide localized optical trapping. PACS 07.60.Pb; 41.75.Ak; 42.15.Eq; 42.65.Jx; 42.79.Bh     

微透镜阵列误差对半导体激光匀化性能的影响

为了减小微透镜阵列误差对匀化光斑的影响,深入研究微透镜阵列光束匀化系统中微透镜阵列相对位置误差对光束匀化性能的影响,设计了一种微透镜阵列光束匀化系统。依据相对位置误差类型的不同,将双列微透镜阵列间六个自由度变化导致的误差分为距离误差、偏移误差以及转动误差进行分析,并对每种误差对光束匀化性能的影响进行了研究。采用6板条条半导体激光器堆栈对上述匀化系统进行实验验证,实现了均匀性为90.75%的光斑,并对系统影响光斑性能的原因进行了分析。     

Fabrication of PDMS microlens array by digital maskless grayscale lithography and replica molding technique

This paper presents a facile and effective method to fabricate microlens array in polydimethylsiloxane (PDMS). The microlens array model is fabricated in photoresist via digital maskless grayscale lithography technique and the replica molding technique is used to fabricate PDMS microlens array. A convex PDMS microlens array with rectangular aperture and concave PDMS microlens array with hexagonal aperture are fabricated. The morphological characteristics of the microlens arrays are measured by microscope and 3D profiler. The results indicate that the profiles of the PDMS microlens arrays are clear and distinct. This method provides a simple and low-cost approach to prepare large area, concave or convex with arbitrary shape microlens array, which has potential application in many optoelectronic devices.     

微透镜阵列光学相控阵扫描技术研究进展

光学相控阵光束扫描技术在激光雷达、空间光通信和光开关等领域拥有巨大的应用潜力。微透镜阵列光学相控阵可以通过微透镜阵列间μm量级的相对位移同时对多个出射光束的二维倾斜相位进行调制,从而实现大角度二维光束扫描,具有出射口径大、结构简单、体积小、微惯性、多功能等优点。首先介绍了微透镜阵列光学相控阵的扫描原理,之后对微透镜阵列光学相控阵国内外的发展现状、应用和现阶段存在的问题进行了阐述,最后对微透镜阵列光学相控阵的发展趋势进行了展望。

     

Analysis of light out-coupling from microlens array

Microlens array has been known to be effective in enhancing the out coupling efficiency of LEDs, OLEDs and other thin film light emitting devices. However, mechanism of efficiency enhancement by use of microlens arrays is still ambiguous, apart from suggestions that it leads to randomization of photons. We have studied the photon dynamics in the presence of microlens arrays and the effect of various parameters e.g. microlens contact angle, absorption and substrate refractive index using ray tracing simulations. Microlens array leads to extraction of a portion of photons outside the escape cone at the cost of reduced extraction from within the escape cone. The reduced extraction from within the escape cone is compensated by multiple reflections from the back surface. Increase in microlens contact angle reduces the number of reflections required for out-coupling hence reducing the absorption in the device.     

微透镜阵列反应离子束蚀刻传递研究

提出了一种微透镜阵列复制的新方法－反应离子束蚀刻法（ＲＩＢＥ）它在工作原理和参数控制等方面较传统的蚀刻方法有很大的先进性，能够实现蚀刻过程的精确控制，本文详细阐述了反应离子蚀刻过程中的蚀刻选择性的控制方法，通过对各种蚀刻参数的控制，最终实现了微透镜阵列在硅等红外材料上面形传递的深度蚀刻，口径φ１００μｍ的Ｆ／２微透镜阵列在硅基底上的传递精度达１：１．０３，无侧向钻蚀。     

紫外衍射微透镜阵列的设计与制备

为了提高紫外焦平面阵列的填充因子,可以通过微透镜阵列与紫外焦平面阵列的集成,以改善紫外焦平面阵列的探测性能。根据标量衍射理论设计了用于日盲型紫外焦平面阵列的128×128衍射微透镜阵列,其工作中心波长为350nm,单元透镜F数为F/3.56。采用组合多层镀膜与剥离的工艺方法制备了128×128衍射微透镜阵列,对具体的工艺流程和制备误差进行了分析,测量了衍射微透镜阵列的光学性能。实验结果表明:衍射微透镜阵列的衍射效率为88%,与理论值95%有偏差,制备误差主要来自对准误差和线宽误差。紫外衍射微透镜阵列具有均匀的焦斑分布,与紫外焦平面阵列单片集成能较好地改善器件的整体性能。     

Determination of Aberration Coefficient of Microoptic Arrays from Axial Confocal Response by Neural Method

We propose a high-speed and parallel method to determine lens aberrations from its confocal axial response. This method analyzes the intensity confocal response including the aberration information of the objective lens by means of neural network algorithm. This method is designed to work parallely for many microlenses, and simultaneously determines aberrations of each element of a microlens array. A prototype system can determine spherical aberration coefficients of a microlens in the range from −0.7λ to 0.3λ with less than 1% RMS error.     

Efficiency improvement and spectral shift of an organic light-emitting device with a square-based microlens array

In this paper, we present and analyze the influences of the fill factor and the height ratio of square-based microlens arrays on the optical characteristics of an organic light-emitting device (OLED). These properties include spectral shift, CIE coordinates, viewing-angle dependence, luminous current efficiency and luminous power efficiency. Both the luminous current efficiency and luminous power efficiency of the OLED were found to increase linearly with increasing the fill factor of microlenses. It is also found that the full width at half maximum (FWHM) of the OLED spectra and CIE coordinate decreased linearly with increasing the fill factor of the microlenses. Besides, the efficiency improvement of the OLED increased with the height ratio of attached microlenses. Compared to the OLED, the luminous current efficiency and luminous power efficiency of the device can be enhanced by 42% and 47%, respectively, by attaching the microlens array having a fill factor of 90% and a height ratio of 0.57. We also observed blue shifts at different viewing angles when microlens arrays were attached to the OLED, which is the evidence that the waveguiding modes are being extracted. In our planar OLED, the peak wavelength blue shifted and the FWHM decreased with increasing the viewing angles due to the microcavity effect.     

Design and fabrication of a microlens array by use of a slow tool servo

In recent years it has become possible to fabricate free-form optics by use of multiaxis ultraprecision machines. Here a 5 x 5 microlens array is fabricated by using an ultraprecision diamond turning machine equipped with four independent axes. Unlike the conventional process where a single diamond tool is used to machine one lens at a time, this research demonstrates the development of an innovative diamond tool trajectory that allows the entire microlens array to be machined in a single operation. The machined microlens array is measured for both curve conformity and surface roughness. Compared to the conventional approach where indexing the workpiece is difficult and unreliable, this process can produce microlenses with accurate geometry and optical surface finish. This unique process is described in detail from optical measurement to machining process design and development to final results. This research also demonstrates the possibility of fabricating any arbitrary shape with the same approach.     

PtSi IRCCD器件用长焦距Si微透镜阵列的制作研究

为了改善PtSi IRCCD器件的红外响应特性,需要添加长焦距微透镜阵列进行焦平面集光,本文提出了一种新的方法—曲率补偿法用于长焦距微透镜阵列的制作.扫描电子显微镜(SEM)显示微透镜阵列为表面极为平缓的方底拱形阵列,表面探针测试结果显示用曲率补偿法制作的微透镜阵列表面光滑,单元重复性好,其焦距可达到685.51μm.微透镜阵列器件与PtSi IRCCD器件在红外显微镜下对准胶合,显著改善了IRCCD器件的光响应特性.     

激光直接光刻制作微透镜列阵的方法研究

介绍了利用激光直接光刻制作８相位台阶菲涅尔衍射微透镜列阵的工艺方法，并对元件的衍射效率及光刻过程中的制作误差进行了分析，透镜列阵在小形Ｓｈａｃｋ－Ｈａｒｔｍａｎｎ波前传感器中得到了应用。     

共光路共模块自适应光学系统中赝相位共轭器件应用分析

研究了角反射器阵列形成赝相位共轭波的能力,计算了其对泽尼克多项式表示的各阶像差的保真度,分析了在共光路共模块自适应光学系统中角反射器阵列与哈特曼－夏克波前传感器二者之间单元数目,位置匹配方面的问题,对失配所带来的误差进行了计算。     

Diffractive Microlens Array Monolithic Integration with PtSi Focal Plane array

Diffractive microlens arrays can completely collect the light at the focal plane and concentrate it into a smaller spot size on the detector plane, the photodetector area can be substantially reduced. Increased gamma radiation hardening and noise reduction result from the decrease in photodetector sensitive area. The diffractive microlens arrays have been designed by considering the correlative optical and processing parameters for PtSi focal plane array. They have been fabricated on the backside of PtSi focal plane array chip by successive photolithography and Ar⁺ ion-beam-etching technique. The alignment of microlens array with PtSi focal plane array was completed by a backside aligner with IR light source. The practical processes and fabrication method are discussed. The performance parameters of PtSi FPA with diffractive microlens array are presented.     

Silicon microlens structures fabricated by scanning-probe gray-scale oxidation

We report on the micromachining of silicon microlens structures by use of scanning-probe gray-scale anodic oxidation along with dry anisotropic etching. Convex, concave, and arbitrarily shaped silicon microlenses with diameters as small as 2 microm are demonstrated. We also confirm the high fidelity of pattern transfer between the probe-induced oxides and the etched silicon microlens structures. Besides the flexibility, the important features of scanning-probe gray-scale anodic oxidation are small pixel size and pitch (of the order of tens of nanometers), an unlimited number of gray-scale levels, and the possibility of creating arbitrarily designed microlens structures with exquisite precision and resolution. With this approach, refractive, diffractive, and hybrid microlens arrays can be developed to create innovative optical components.