Design of a tunable ultraviolet filter using metallodielectric photonic crystal

A theory to design a tunable ultraviolet filter using a 1-D metallodielectric photonic crystal composed of alternate layers of MgF
₂
and Co is proposed. It is possible to get different ranges of ultraviolet spectrum transmitted through the structure by varying the angle of incidence light. Due to high refractive index contrast in the present structure, regions of transmission separated by well-defined regions of high reflectivity (the photonic band gaps) are obtained with only 12 periods. The use of small number of periods in the present filter structure has advantages of small filter size, low weight and cost.