Spherical Micro-lens Array of PMMA Produced by Micro-molding

Micro-lens （ML） and Micro-lens array （MLA） are important optical components widely used in many fields; Soft-lithography, a vital little process technology, has its unique performance to produce ML and MLA; The cylinder and spherical MLA of polymethyl methacrylate （PMMA） were successfully obtained by micromolding inSoft-lithography. Some suitable experimental parameters in the process were discussed, and the imaging property of the MLA was also studied simply.

Crosstalk-free integral imaging display based on double plano-convex micro-lens array

A crosstalk-free integral imaging display consisting of a display panel and double piano-convex micro-lens array is proposed. The double piano-convex micro-lens array includes two micro-lens arrays, A and B. Micro-lens array A is used to eliminate crosstalk by completely reflecting crosstalk lights. Micro-lens array B, located near microqens array A, is used to display three-dimensional images. Computer simulations based on ray-tracing are conducted. Crosstalk-free reconstruction images may be clearly observed from the simulation results.

High-speed, large-area and high-precision fabrication of aspheric micro-lens array based on 12-bit direct laser writing lithography

Aspheric micro-lens array(AMLA),featured with low dispersion and diffraction-limited imaging quality,plays an important role in advanced optical imaging.Ideally,the fabrication of commercially applicable AMLAs should feature low cost,high precision,large area and high speed.However,these criteria have been achieved only partially with conventional fabrication process.Herein,we demonstrate the fabrication and characterization of AMLAs based on 12-bit direct laser writing lithography,which exhibits a high fabrication speed,large area,perfect lens shape control via a three-dimensional optical proximity correction and average surface roughness lower than 6 nm.In particular,the AMLAs can be flexibly designed with customized filling factor and arbitrary off-axis operation for each single micro-lens,and the proposed pattern transfer approach with polydimethylsiloxane(PDMS)suggests a low-cost way for mass manufacturing.An auto-stereoscopic-display flexible thin film with excellent display effect has been prepared by using above technology,which exhibits a new way to provide flexible auto-stereoscopic-display at low cost.In brief,the demonstrated fabrication of AMLAs based on direct laser writing lithography reduce the complexity of AMLA fabrication while significantly increasing their performance,suggesting a new route for high-quality three-dimentional optical manufacturing towards simplified fabrication process,high precision and large scale.

Broadband photonic structures for quantum light sources

Quantum light sources serve as one of the key elements in quantum photonic technologies. Such sources made from semiconductor material, e.g., quantum dots (QDs), are particularly appealing because of their great potential of scalability enabled by the modern planar nanofabrication technologies. So far, non-classic light sources based on semiconductor QDs are currently outperforming their counterparts using nonlinear optical process, for instance, parametric down conversion and four-wave mixing. To fully exploring the potential of semiconductor QDs, it is highly desirable to integrate QDs with a variety of photonic nanostructures for better device performance due to the improved light-matter interaction. Among different designs, the photonic nanostructures exhibiting broad operation spectral range is particularly interesting to overcome the QD spectral inhomogeneity and exciton fine structure splitting for the generations of single-photon and entangled photon pair respectively. In this review, we focus on recent progress on high-performance semiconductor quantum light sources that is achieved by integrating single QDs with a variety of broadband photonic nanostructures i.e. waveguide, lens and low-Q cavity.

A Novel Artificial Superposition Compound Eye

A new artificial superposition compound eye model is presented based on micro-lens array. In all compound eyes,it has the advantages of small volume,light weight,wide FOV,high sensitivity and much higher energy utilization ratio. Nevertheless,its structure is relatively complicated,especially the GRIN medium in the crystalline cone. Therefore,the modeling,analysis and fabrication for it are burdensome. In the established model,the GRIN is replaced by a curved micro-lens array. Thus,the modeling,analysis and optimization process are simple,and the components of artificial superposition compound eye are easy to be fabricated. The system is modeled by ZEMAX software. With the help of raytracing,its principle is analyzed,and the sensitivity comparison between the superposition compound eye and the apposition compound eye is done. The model's validity is proven.

Direct generation of a stable multi-beam pulsed 355 nm UV laser based on a micro-lens array

Multi-beam laser processing is a very popular method to improve processing efficiency. For this purpose, a compact and stable multi-beam pulsed 355 nm ultraviolet(UV) laser based on a micro-lens array(MLA) is presented in this Letter. It is worth noting that the MLA is employed to act as the spatial splitter as well as the coupling lens. With assistance of the MLA,the 1064 nm laser and 532 nm laser are divided into four sub-beams and focused at different areas of the third-harmonic generation(THG) crystal. As a result, the multi-beam pulsed 355 nm UV laser is successfully generated inside the THG crystal. The measured pulse widths of four sub-beams are shorter than 9 ns. Especially, the generated four sub-beams have good long-term power stability benefitting from the employed MLA. We believe that the generated stable multi-beam355 nm UV laser can meet the requirement of high-efficiency laser processing, and the presented method can also pave the way to generate stable and long-lived multi-beam UV lasers.

Atomically thin optical lenses and gratings

Two-dimensional(2D)materials have emerged as promising candidates for miniaturized optoelectronic devices due to their strong inelastic interactions with light.On the other hand,a miniaturized optical system also requires strong elastic light–matter interactions to control the flow of light.Here we report that a single-layer molybdenum disulfide(MoS2)has a giant optical path length(OPL),around one order of magnitude larger than that from a single-layer of graphene.Using such giant OPL to engineer the phase front of optical beams we have demonstrated,to the best of our knowledge,the world’s thinnest optical lens consisting of a few layers of MoS2 less than 6.3 nm thick.By taking advantage of the giant elastic scattering efficiency in ultra-thin high-index 2D materials,we also demonstrated high-efficiency gratings based on a single-or few-layers of MoS2.The capability of manipulating the flow of light in 2D materials opens an exciting avenue towards unprecedented miniaturization of optical components and the integration of advanced optical functionalities.More importantly,the unique and large tunability of the refractive index by electric field in layered MoS2 will enable various applications in electrically tunable atomically thin optical components,such as micro-lenses with electrically tunable focal lengths,electrical tunable phase shifters with ultra-high accuracy,which cannot be realized by conventional bulk solids.

Recent advancements in optical microstructure fabrication through glass molding process

Optical microstructures are increasingly applied in several fields, such as optical systems, precision measurement, and microfluid chips. Microstructures include microgrooves, microprisms, and microlenses. This paper presents an overview of optical microstructure fabrication through glass molding and highlights the applications of optical microstructures in mold fabrication and glass molding. The glass-mold interface friction and adhesion are also discussed. Moreover, the latest advance- ments in glass molding technologies are detailed, including new mold materials and their fabrication methods, viscoelastic constitutive modeling of glass, and micro- structure molding process, as well as ultrasonic vibration- assisted molding technology.