An excimer-pumped β-BaB2O4 optical parametric oscillator tunable from 354 nm to 2.370 μm

A pulsed singly resonant optical parametric oscillator (OPO) has been constructed which can provide tunable coherent radiation over the entire wavelength range extending from 354 nm in the near ultraviolet, throughout the visible, to 2.370 μm in the near infrared using a single β-BaB₂O₄ crystal. The oscillator is pumped at 308 nm by a pulsed narrow band injection-seeded XeCl excimer laser in a near-field pumping configuration, and energy conversion efficiencies (optical-to-optical) in excess of 10% have been obtained in a 12-nm-long crystal across the OPO tuning range. The requirements placed upon the spectral and spatial coherence of the pump laser for optimum OPO operation are discussed. Experimental results on several oscillator parameters, including tuning range, oscillation threshold, energy conversion efficiency, and spatial and temporal characteristics, are presented