KBBF family crystals and deep UV harmonic generation

KBBF family crystals, ABe2BO3F2 (A=K, Rb, Cs), are the only type of crystals that can generate deep-UV laser light by direct harmonic generations. The talk starts with briefly introduction of the historical background of the discovery of the borate nonlinear optical (NLO) crystals, followed by the description of the growth, structure, basic properties of the KBBF family crystals. Focuses will be given to the recent progresses on the generation of deep-UV lights, e.g. 120mW at 177.3nm and 1.2W at 200nm. Examples of applications of such deep UV light will be discussed at the end of the talk; which includes: super-high resolution of photoemission spectrometers, photon-electronic emission microscope, etc.