Microlens arrays are used in different applications like displays, optical computing, machine vision, astronomy, 3D imaging, laser-fiber coupling, micro-machining, and others. Such applications require high efficiency and non-gaussian uniformity. In some industries, refractive microlenses are used as an alternative to applications that demand miniaturization and minimized costs of alignment packaging.
Microlens arrays are used to homogenize a variety of contemporary light emitters from line-narrowed excimer lasers to high-power LEDs. They are made from UV-grade fused silica, giving an excellent performance from 193nm to 2.5μm. Manufacturers of micro lens arrays use standard semiconductor technologies that yield accurate shaping of lens profile and precise positioning of lenses within an array.
Microlens arrays are available in the following configurations:
- Square arrays. These microlens arrays come in standard 10mm x 10 mm configuration in different lens pitch and focal length options. They are often used for beam homogenization and shaping, providing spot patterns or a square flat-top pattern. A high fill factor is featured by the lenses that eliminate zero-order hot spots in the illuminated field. Usually, square lenses are utilized in pairs and in conjunction with a PCX lens. These microlenses are typically used in welding, fiber coupling, laser ablation, and drilling.
- Fly’s eye condensers arrays. These come in 5mm and 10 mm square configurations. Manufacturers design them for flat-top and line generation. These arrays are a monolithic assembly of dual-surface cylindrical micro lenses that create adjustment-free condensers. These microlenses are often used in applications that require a big illuminated field that has a short working distance like solar simulation, medical laser user, UV-curing, and fluorescence microscopy.
Applications of Microlens Arrays in Optical Communications
Multi-channel optical communication systems require arrays to couple between laser sources, waveguide and fiber arrays, as well as optical switching and multiplexing. Microlens arrays are the best solution that offers a precise and monolithic component for array collimation and coupling. These microlens arrays can be made from synthetic fused silica and organized in uniform or randomized 1C or 2D arrangements. Arrays manufacturers design their products to be stable, have monolithic structure, efficient transformation, increased transmission, and homogenization and beam shaping. With some manufacturers, their direct-write process doesn’t require a mask set or custom tooling. This allows customized designs to be commissioned at a lower cost than other alternatives. Apart from indicating reduced costs, this also indicates the possibility of trying new ideas and optimizing performance that results from in situ testing.