No abstract

We have studied the optical second harmonic generation (SHG)

We m easure the nonlinear optical d coefficients of potassium titan y l phosphate relative to d 11 of quartz and use these to calculate th e effective coefficient d eff for type-I phase matching. We compare the calculations w ith a variety of m easurem ents and determ ine th a t th e signs of th e different d coefficients are all th e same.

Since the discovery of the promising nonlinear optical (nlo) properties of KTA (larger d-coefficients and spectral range than KTP) there has been some confusion about the precise nlo coefficients.

M.Towrie@RL.AC UK, Tel. 01235 446141, Fax. 01235 445888 1. IntroductionMany time-resolved spectroscopy techniques require two broadly and independently tunable, synchronised light pulses. Recent advances in short pulse laser technology and non-linw crystal materials have lead to rapid development of optical parametric oscillators (OPOs) and travelling wave optical parametric amplifiers (OPAs) capable of meeting these requirements. Our aim was to develop a multi-kilohertz repetition rate OPA system for femtosecondlpicosecond, pump and probe time-resolved absorption and resonance Raman spectroscopies. We believe this work reports, for the first time, on synchronously pumped travelling wave OPAs. The design similar to that described in [I] was adopted for the development of the OPAs