形成连续微光学元件的灰度掩模图形生成方法

针对利用灰度掩模制作连续微光学元件的方法 ,介绍了从元件结构到灰度图形的转换 ,灰度图形的修正 ,灰度图形的数字化以及图形编码等关键步骤。最后给出生成微透镜列阵掩模图形的实例。     

菲涅耳微透镜列阵衍射效率的测试

介绍了测量菲涅耳微透镜列阵的衍射效率的两种不同方法及其系统，方法简单易行，并实际测试了具有微小单元尺寸的菲涅耳微透镜列阵的衍射效率。     

微透镜列阵与红外探测器列阵集成芯片的研究

在分析微透镜列阵光聚能原理的基础上,针对背照式256290铂硅红外焦平面探测器列阵 的结构参数,设计了衍射微透镜列阵,使入射光通过硅基底聚焦至探测器的各个光敏面上, 提高光能利用率从而增强探测能力。实验获得了微透镜列阵与红外焦平面集成芯片,并在热成像中取得了良好的结果。     

微透镜列阵衍射效应所致的串扰

本文分析了微透镜列阵衍射效应的影响因素,推导出了微透镜焦平面上光强分布的解析表达式,对菲涅尔数评价衍射效应的物理含义给予了合理的解释.并利用ZEMAX软件对微透镜列阵进行仿真,基于惠更斯子波直接积分的算法计算得到了微透镜列阵焦平面上的光场强度分布.通过比较不同条件下所得到的计算结果,验证了以菲涅尔数作为微透镜列阵衍射效应评价依据的的合理性,同时验证了以菲涅尔数判断焦斑间串扰的可行性.     

微透镜列阵的光敏热成形新方法

首次在国内用光敏玻璃热成形方法研制了一种新型的微透镜列阵，采用具有特定化学组分的光敏玻璃材料，在普通的紫外平行光束照射下进行感光和热处理，制得了孔径为４００μｍ的微透镜列阵。     

微透镜列阵成像光刻调焦方法

本文分析了离焦量对微透镜列阵成像光刻图形质量的影响,给出了系统离焦量的容差.同时提出了一种结构简单、可应用于微透镜列阵成像光刻系统调焦的新方法.并将基于该调焦方法的实验装置应用于微透镜列阵成像光刻系统,进行了光刻实验.实验表明,利用该方法时微透镜列阵成像光刻系统调焦,可得到接近微透镜列阵极限像质的光刻图形.     

误差扩散法编码设计制作微光学元件

以发展微光学元件制作新方法为目标,提出利用误差扩散编码方法设计灰阶编码掩模制作微光学元件。此方法同其他编码方法相比,具有量化效果好、衍射效率高、制作文件小、计算速度快、通用性好等优点。用此方法对制作微透镜的掩模进行了设计,利用预校正法和边缘增强法相结合的方法对掩模进行了优化,并对曝光、显影过程进行了模拟,得到了满意的结果。     

衍射微透镜列阵质量评价方法研究

根据实际工程需要 ,对用于萨克 -哈特曼波前传感器的二元衍射微透镜列阵衍射效率的评价方法进行了研究。导出了制作误差与衍射效率的关系式 ,研究了由测得的制作误差评估衍射效率的方法 ,并建立了一套测量系统。     

湿法制作连续微透镜列阵新方法

制作连续微透镜列阵中主要的问题就是浮雕的深度和浮雕面形的控制,已有的微透镜列阵制作方法不能很好地解决;本文提出了一种利用干法和湿法蚀刻结合在硅片上制作连续深浮雕微透镜列阵的新方法,得到了深度４０μｍ的微柱面和旋转抛物面微透镜列阵。     

二元位相匹配衍射透镜的研究与应用

针对大数值孔径衍射透镜制作难、衍射效率低的问题，探讨了用位相匹配原理对元件结构参数优化设计的方法，研制出８台阶二元衍射位相匹配透镜列阵，达到了预期的效果。采用该方法设计的大数值孔径红外锗透镜和为光聚能器，应用在提高红外探测器性能的实验中。     

Efficient implementation of a spatial light modulator as a diffractive optical microlens array in a digital Shack-Hartmann wavefront sensor

A traditional Shack-Hartmann wavefront sensor (SHWS) uses a physical microlens array to sample the incoming wavefront into a number of segments and to measure the phase profile over the cross section of a given light beam. We customized a digital SHWS by encoding a spatial light modulator (SLM) with a diffractive optical lens (DOL) pattern to function as a diffractive optical microlens array. This SHWS can offer great flexibility for various applications. Through fast-Fourier-transform (FFT) analysis and experimental investigation, we studied three sampling methods to generate the digitized DOL pattern, and we compared the results. By analyzing the diffraction efficiency of the DOL and the microstructure of the SLM, we proposed three important strategies for the proper implementation of DOLs and DOL arrays with a SLM. Experiments demonstrated that these design rules were necessary and sufficient for generating an efficient DOL and DOL array with a SLM.     

Laser direct-write gray-level mask and one-step etching for diffractive microlens fabrication

High-efficiency diffractive optical elements can be achieved by an increase in the number of phase levels. We present a technique for laser direct-write gray-level masks on high-energy-beam-sensitive glass and one-step etching on the gray-level mask plate for the production of high-efficiency diffractive optical elements. Sixteen-phase-level diffractive microlenses and microlens arrays with a focusing efficiency of approximately 94% have been realized by use of the one-step nonphotolithographic fabrication technique.     

Extensible, Low-Chromatic-Sensitivity, All-diffractive-Optics Relay for Interconnecting Optoelectronic Device Arrays

For free-space optical interconnections between optoelectronic chips to reach commercial realization, the technology must provide high-density optical channels in a simple, inexpensive, and easily aligned package. Although point-to-point connections with microlens pairs can provide densities of several thousand channels per square centimeter, the Gaussian nature of the beams limits the connection range to a few millimeters. We propose an arrangement of microlens pairs with an intermediate relay lens that significantly increases the connection distance. This basic setup can be tiled laterally across large chips to form extensible arrays. The optical design is constructed entirely with diffractive elements because of the low chromatic sensitivity over a range of approximately ?10% around the design wavelength. We derive the lateral positioning error at the image by using a simple ray trace, and we show the effect of Gaussian beams. We experimentally demonstrate the low chromatic sensitivity for a system with an interconnection distance of 64 mm. Finally, we demonstrate the interconnection of two linear arrays of multimode fibers with two adjacent channels operating at data rates of hundreds of megabits per second.     

大数值孔径微透镜阵列激光扫描

提出微透镜阵列与转镜相结合的大口径激光光束扫描方法。采用机械制模法制作微透镜阵列模板 ,然后采用模压法制作光学微透镜阵列 ,其子口径为 2 mm× 2 mm,数值孔径为 0 .2 ,阵列数为 8× 8。并进行了扫描测试实验 ,扫描角达± 6.56°。     

Replication of Microlens Arrays by Gas-Assisted Hot Embossing

This article reports an effective method for mass-production of 300 × 300 microlens arrays. A microlens array master is formed by imprint lithography and photo-resist reflow at room temperature. The electroforming is then applied to fabricating the Ni mold from the master, followed by the gas-assisted hot embossing to replicate the microlens arrays. The isotropic gas pressure on the plastic film against the Ni mold produces plastic microlens array of high quality and uniformity. The effects of processing parameters including the processing temperature, pressure, and time on the replication quality of microlens arrays were investigated. The experimental results show that the filling of molded microlens significantly increases as the processing temperature and pressure increase. Under the condition of 180°C, 3.9 MPa for gas pressure, and 90 seconds processing time, the arrays of polycarbonate microlens of diameter 150 µm and pitch 200 µm have been successfully replicated. The deviation of replicated microlens from the mold is less than 0.25%. Compared with the conventional hot embossing process, the new replication method offers more uniform embossing pressure distribution. The great potential for replicating microlens array on large plastic films with high productivity and low cost was demonstrated.     

Reduction photolithography using microlens arrays: applications in gray scale photolithography

This paper describes the application of reduction photolithography, using arrays of microlenses and gray scale masks, to generate arrays of micropatterns having multilevel and curved features in photoresist. This technique can fabricate, in a single exposure, three-dimensional microstructures (e.g., nonspherical microlens arrays) over areas of approximately 2 x 2 cm2. The simple optical configuration consisted of transparency film (having centimeter-sized features) as gray scale photomasks, an overhead projector as the illumination source, and arrays of microlenses as the size-reducing elements. Arrays of 40- and 100-microm lenses achieved a lateral size reduction of approximately 10(3) and generated patterns of well-defined, multilevel structures; these structures may find use in applications such as diffractive optics.     

Analysis of a cylindrical microlens array with long focal depth by a rigorous boundary-element method and scalar approximations

We investigated the focal characteristics of open-regional cylindrical microlens arrays with long focal depth by using a rigorous boundary-element method (BEM) and three scalar methods, i.e., a Kirchhoff and two Rayleigh-Sommerfeld diffraction integral forms. Numerical analysis clearly shows that the model cylindrical microlens arrays with different f-numbers can generate focusing beams with both long focal depth and high transverse resolution. The performance of the cylindrical microlens arrays, such as extended focal depth, relative extended focal depth, diffraction efficiency, and focal spot size, is appraised and analyzed. From a comparison of the results obtained by the rigorous BEM and by scalar approximations, we found that the results are quite similar when the f-number equals f/1.6; however, they are quite different for f/0.8. We conclude that the BEM should be adopted to analyze the performance of a microlens array system whose f-number is less than f/1.0.     

Arrays of anamorphic phase-matched Fresnel elements for diode-to-fiber coupling

A method for designing microlens arrays that inherently takes into account application requirements and fabrication constraints is presented. Elements with numerical apertures of up to 0.5 have been designed and fabricated by laser beam writing in photoresist and replication in plastic material. In a laser-diode-to-fiber array coupling experiment, an overall optical throughput of 60% was achieved. By means of anamorphic microlens arrays, correction of the laser-diode longitudinal astigmatism and circularization of the image-plane irradiance distribution are demonstrated.     

Polymer-based flexible microlens arrays with hermaphroditic focusing properties

Polymer microlens arrays with hermaphroditic focusing behaviors are demonstrated. Each microlens in an arrays exhibits either converging or diverging focus, depending on the polarization direction of the incident light. A polymer film with patterned microlens arrays is flexible, lightweight, and ultrathin (approximately 50 microm). Details of the lens structure, device fabrication, and lens performance are described.