Chirped mirror

A non-chirped dielectric mirror. This electron microscope image of a tiny circular piece of dielectric mirror being cut out from a larger substrate clearly shows the periodic layered structure of the mirror. The spacing of each layer determines the wavelength of light that is reflected by that layer. In a chirped dielectric mirror the deeper layers would be thicker than the surface layers to reflect longer wavelengths of light and create the chirped effect.

A chirped mirror is a dielectric mirror with chirped spaces—spaces of varying depth designed to reflect varying wavelengths of lights—between the dielectric layers (stack).

Chirped mirrors are used in applications like lasers to reflect a wider range of light wavelengths than ordinary dielectric mirrors, or to compensate for the dispersion of wavelengths that can be created by some optical elements.[1] Chirped mirrors are also found in structurally colored biological systems,[2] including the shiny golden and silver color of certain beetles' elytra, e.g. those of the Ruteline genus Chrysina. In these cases, the chirped mirror generates complex color (such as gold or silver) when illuminated by white light by simultaneously reflecting a broad range of monochromatic colors.

  1. ^ Robert Szipöcs, Kárpát Ferencz, Christian Spielmann, and Ferenc Krausz, "Chirped multilayer coatings for broadband dispersion control in femtosecond lasers," Opt. Lett. 19, 201–203 (1994)
  2. ^ Cook, Caleb Q.; Amir, Ariel (20 December 2016). "Theory of chirped photonic crystals in biological broadband reflectors". Optica. 3 (12): 1436–1439. arXiv:1608.05831. doi:10.1364/OPTICA.3.001436. ISSN 2334-2536. S2CID 85551119.