Simple, highperformance type II bBaB2 O4 （简单,高效能的II型bBaB2 O4）.pdfVIP

Simple, high-performance type II -BaB2O4 optical parametric oscillator Sheng Wu, Geoffrey A. Blake, Zhaoyang Sun, and Jiwu Ling A visiblenear-IR optical parametric oscillator OPO based on type II phase matching in -BaB O BBO 2 4 is described. Pumped at 355 nm, this OPO covers 410–2500 nm completely with a single set of standard Nd:YAG cavity optics. The output efficiency is 25%, the linewidth of the OPO is narrower than 1–2 cm1 without the use of gratings or etalons, and the signal-beam divergence is 400 rad. Three type I BBO doubling crystals are used to extend the tuning range from 208 to 415 nm. Doubling efficiencies as high as 40% are easily obtained. The reasons for the high doubling and overall system efficiency are discussed. © 1997 Optical Society of America Key words: Type II -barium borate optical parametric oscillator, doubling efficiency. Optical parametric oscillators OPO’s based on type I doubling efficiency, and covers the same tuning range as phase matching in -BaB O BBO crystals have been BBO OPO’s based on type I interactions. 2 4 rapidly developing over the past several years. Type I To the best of our knowledge, nanosecond-pulse- BBO OPO’s give high efficiency and wide tunability,1–4 length OPO’s based on type II phase matching in BBO particularly when pumped at 355 nm. However, the crystals have been reported only once before.7 There inherent gain linewidth in type I BBO parametric oscil-