Monolithic wavelength converter for ultraviolet light by use of a Gd_(x)Y_(1-x)Ca_(4)O(BO_(3))_(3) crystal

摘要

Gd_(x)Y_(1-x)Ca_(4)O(BO_(3))_(3) (GdYCOB) is a promising nonlinear optical crystal that shows high effective nonlinearity d_(eff), noncritical phase matching, and high chemical stability. We report on the fabrication and characteristics of a monolithic wavelength converter, which generates ultraviolet light by the incidence of a 1.064 (mu)m near-infrared laser. The converter consists of GdYCOB for third-harmonic generation, KTiOPO_(4)(KTP) for second-harmonic generation, and a wave plate. GdYCOB has the advantage of an extremely wide angular acceptance bandwidth, whereas KTP exhibits a high effective nonlinear coefficient and a broad temperature bandwidth. Consequently the combination of these crystals results in highly efficient and stable ultraviolet conversion for constructing a compact and robust ultraviolet laser.