Photorefractive properties of Bi4Ge3O12 crystals in the ultraviolet spectral range

To the best of our knowledge, only preliminary studies of photorefractive effects in the ultraviolet (UV) spectral range have been reported up to now, e.g. in KH2PO4 [1], RbZnBr4 [2] (both at low temperatures), and in LiNbO3 [3, 4] and LiTaO3 [5] in the near UV. Photorefractive materials operating in the UV however could be very useful for all types of coherent optical beam interactions, e.g. beam amplification, dynamical holography, phase-conjugation or photolithographic applications where the use of shorter wavelengths leads to an increased resolution.