Broadband sum-frequency mixing in some recently developed nonlinear optical crystals

Abstract

We present a very simple and straightforward approach for the generation of broadband radiation in the visible region covering 397 to 529 nm by taking advantage of the angular dispersion of the broadband (0.8- to 1.6-μm) idler radiation of a Ti:sapphire second-harmonic (i.e., 395 nm)-pumped type I noncollinear optical parametric amplifier (NOPA). Type I broadband sum-frequency mixing (SFM) between the Ti:sapphire laser fundamental radiation (790 nm) and the octave-spanned carrier-envelope-phase (CEP)-locked idler radiation from a broadband NOPA is considered for generation of broadband radiation in several relatively recently developed borate crystals. Moreover, it is also shown that by applying simple SFM, it is possible to obtain a very large bandwidth in a 5-μm-thick crystal without requiring any angularly dispersed input radiation. Furthermore it is found that the performance of the most recently developed KBe 2 BO 3 F 2 crystal is the best among all the available borate group crystals.