A lens so small that it is within a diameter is called microlens arrays. The unique characteristic of the micro lens is that its small size allows it to be of a simple design ensuring high quality. Along with coupling to optical fibers, these lenses are often also used to increase light collection. With a wide category available, there are different types of optical lenses that you can choose from.
Plano convex shaped lens
One of the common micro lens types is Plano Convex shaped lens. It is very useful in concentrating an Extreme Power Q-Switched Laser Pulses onto the mark. Due to the concentrated beam, it is possible for Plano convex to provide condensed distortion from spherical aberrations. Not just that, adding to the advantage is the fact that it is way cheaper than bi-convex lenses.
There are two ways in which you can utilize micro lens arrays. These are the most common two ways preferred by most individuals working with micro lens arrays.
Mounted micro lens arrays:
This type of Micro lens is very well-suited with the standard optic mounts. Almost all the characteristics of mounted micro lens arrays are similar to that of an un-mounted micro lens. One of the major advantages seen in the other two types of usage in the micro lens is that the silica substrate provides excellent transmission characteristics from the UV to the IR.
Un-mounted micro lens arrays:
This type is beneficial as it comes with a fused silica substrate. This substrate makes it easier to work with Micro lens arrays. It usually contains a square grid arrangement of micro lens arrays. Usually, you can view this type in Custom-Built Shack-Hartmann Wavefront Sensors. Not just that, it is accompanied with an AR coating or AR mask.
These types of lenses are molded by means of photolithographic methods centered on semiconductor processing technology, which permits for exceptional consistency in the figure and location of each micro lens. Unlike some micro lens arrays produced from readymade epoxy, this process creates micro lens arrays where the spot size of each micro lens is nearly diffraction limited. Micro lens arrays when mounted possess a chrome mask that cellblocks light from being diffused through the areas between micro lenses, thereby expanding the contrast. The un-mounted lens arrays and their mounted versions possess a broadband AR coating on equal sides to decrease the exterior reflections.
In this way, all these types are being used differently to serve different purposes.