Second harmonic generation from KBBF crystal in the deep ultraviolet

Summary from only given. The simplest way to produce deep UV coherent light is to use the fourth harmonic generation of a Ti:sapphire laser. So far, only KBe/sub 2/BO/sub 3/F (KBBF) crystals can be used to achieve this. We succeeded in growing platelike KBBF crystals. The platelike crystals can be polished but is still too thin to be cut along the phase-matching direction for fourth harmonic generation. To solve this problem, we adopted a special prism coupling technique (PCT) to avoid the difficulty in cutting the crystal. We measured the optical transmission spectrum in the UV region with a spectrophotometer.