It's important to push along in this direction and see if we can find materials and fabrication approaches that will make this happen. We do know if we can do what the theory says, it will happen. The familiar metallic mirror is omnidirectional, which means it reflects light from every angle. It also absorbs a significant portion of the incident light in the optical regime. Dielectric mirrors, unlike metals, do not conduct electricity, so their response to light can be very different.
Light travels in dielectric materials at speeds that are lower than in air.
When light traveling in a particular direction through one type of dielectric material encounters another type, part of the light is reflected while the other part is transmitted at a different angle. Dielectric mirrors are made of multiple layers of transparent dielectric materials. Such materials, which can be made to be extremely low loss compared to their metal counterparts, are used to reflect a prescribed range of frequencies coming from within a limited set of angles. Dielectric mirrors are used in devices such as lasers, which need low losses and high reflectivity. The new kind of mirror developed in 1998 by Drs.