Cherenkov-type phase matching in bulk KDP crystal

The conical second harmonic emission from a bulk KDP crystal was detected and interpreted in terms of Cherenkov-type phase matching. In contrast to the models describing conical emission from a dense atomic medium, the present model is simple, independent of the intensity of pump and generated radiation and does not require including additional nonlinear effects, such as self-focusing and self-trapping. The experimentally registered parameters are in good agreement with theoretical data. The differences between Cherenkov-type phase matching and Cherenkov-type emission are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.