Plano-convex lenses are positive focal length elements with one spherical surface and one flat surface. Plano convex lenses converge parallel light, correct the deflected light and convert point light sources into parallel light.
Plano concave lens bend parallel input rays so they diverge from one another on the output side of the lens and hence have a negative focal length.
The double convex lens/mirror is symmetrical across both its horizontal and vertical axis. Each of the lens's two faces can be thought of as originally being part of a sphere. The fact that a double convex lens/mirror is thicker across its middle is an indicator that it will converge rays of light that travel parallel to its principal axis.
A double concave lens/mirror has a negative focal length, thereby causing collimated incident light to diverge. The double concave lens/mirror has an equal radius of curvature on both sides of the lens. They are generally used to expand light or increase focal length in the existing system, such as beam expander and projection systems.
Ball lenses are completely spherical lenses most commonly used to couple light in and out of fibers. Half-ball lenses are hemispheres.Half-Ball lenses are ideal for applications such as fiber communication, endoscopy, microscopy, optical pick-up devices, and laser measurement systems.
Meniscus lens is divided into positive and negative lunar lenses.One side of a meniscus lens is convex and the other side is concave.
An achromatic lens, also referred to as an achromat, typically consists of two optical components cemented together, The achromatic design also helps minimize spherical aberrations.
