Micro lens array is considered as one of the biggest applications in the optical world to date, which is used for laser collimating and focusing, laser-to-fiber coupling, fiber-to-fiber coupling, and fiber-to-detector coupling.
Apart from its basic functionality, this article covers some unique facts about microlens array:
Different Microlens Arrays Have Different Working Principle:
- Based on the construction, some Micro-lens simply works as traditional large lenses (also called a refractive lens). Their significant feature is they can radically change the optical phase and thickness of the device.
- If the optical manufacturer’s aim is to lower the thickness of the lens, the Fresnel lens is used to reflect the light by a set of concentric curved surfaces. With such type of lens, one can easily optimize the phase properties and adjust the dimension of the lens.
- As the name suggests, Refractive and Diffractive microlens array are based on the phenomenon of refraction and diffraction respectively. In the practical world, the refractive lens is useful in large devices while the latter is useful for small dimensional elements such as grating spectrometers, beam splitters, and photomasks.
- Recently, scientists have also developed Gradient-index lenses (also called a GRIN) that are typically used to assemble and re-image the output of the fiber.
The Different Microlens Array Is Made From Different Techniques: Construction and fabrication of different microlenses involve a number of complex techniques, which are as follows:
- In the case of customized designs, Micro-lenses are manufactured by using advanced computer-controlled laser writing technologies.
- The small or mid-sized optical manufacturers rely on traditional techniques such as lithography, photolithography, and computer-generated holograms.
- In the case of bulk manufacturing, Microlens is engineered with the help of embossing or injection molding techniques.
Important Characteristics Of Microlens Array: Depending on the manufacturing process and client’s requirements, Microlens can vary:
- Based on aspects like spectral ranges, optical material, and the layers of anti-reflection coatings, the lens can be optimized accordingly.
- Each type of Microlens features different values of lens pitch- ranging from a few micrometers to hundreds of micrometers.
- The basic features that mark the difference between lenses are diameter, focal length, and wavelength.
- Although microlenses are available in a circular or cylindrical shape, these shapes can be easily customized as per the customer’s request.
Microlens array is elevating the overall efficiency of the devices in major industries. Its features such as heat resistance, durability, easy configuration, and customization are attracting new players in the market as well.