Experimental realization of multi, zero, dual order and achromatic gypsum wave plate in a wavelength range 400–1000 nm

In a wide wavelength range (400–1000 nm), the birefringence channeled spectra produced from interference of polarized white light is used to extract the birefringence Δn of gypsum crystal. In the same spectral range, the dispersion of gypsum birefringence is extracted and fitted to Cauchy dispersion function with relative error in finding Δn of an order 2×10−4. The calculated retardation introduced by gypsum crystal confirms that gypsum plate of thickness ≈2 mm can act as a multiple order half and quarter wave plate for most of Ar+, Kr and He–Ne laser lines. Zero order full, half and quarter wave plate are experimentally realized at 675 nm, 633 nm and 633 nm, respectively. In addition, a dual wavelength quarter wave plate working at 550 nm and 930 nm is also experimentally obtained. Finally, in the same spectral range quarter and half achromatic wave plate are practically realized by combining gypsum with MgF2 crystal.