Knight Optical (UK) Ltd Mica Retarder 1/4 wave 830nm 25mmdia x 3mmthk RYM2509

Mica retarders present a cost effective alternative to traditional quartz types and benefit from being moderately achromatic. Mica retarders are made from thin layers of weakly birefringent mica held between two glass plates for ease of handling. The thickness of the mica correlates to the operating wavelength of the retarder. Because mica retarders are zero-order devices they exhibit low dispersion and angular sensitivity and can be used over a large wavelength range. Mica also gives uniform retardance across the aperture. Note: These retarders are being discontinued. Once parts are out of stock they will not be replenished