A birefringence based light modulator that works in the wavelength region of < 350 nm plays a vital role in DUV beam shaping, high density data storage, semiconductor micro-nano processing and photolithography. Actually, a series of DUV birefringent materials, including single crystals of α-BBO, MgF2, Ca(BO2)2, and α-SnF2, have thus been made and commercially used. However, these birefringent elements have fixed birefringence, limiting their capability of continuous light modulation.
