Demirbas Umit, Schmalz Michael, Sumpf Bernd, Erbert Götz, Petrich Gale S, Kolodziejski Leslie A, Fujimoto James G, Kärtner Franz X, Leitenstorfer Alfred
Department of Physics and Center for Applied Photonics, University of Konstanz, D-78464 Konstanz, Germany.
Opt Express. 2011 Oct 10;19(21):20444-61. doi: 10.1364/OE.19.020444.
We report compact, low-cost and efficient Cr:Colquiriite lasers that are pumped by high brightness tapered laser diodes. The tapered laser diodes provided 1 to 1.2 W of output power around 675 nm, at an electrical-to-optical conversion efficiency of about 30%. Using a single tapered diode laser as the pump source, we have demonstrated output powers of 500 mW and 410 mW together with slope efficiencies of 47% and 41% from continuous wave (cw) Cr:LiSAF and Cr:LiCAF lasers, respectively. In cw mode-locked operation, sub-100-fs pulse trains with average power between 200 mW and 250 mW were obtained at repetition rates around 100 MHz. Upon pumping the Cr:Colquiriite lasers with two tapered laser diodes (one from each side of the crystal), we have observed scaling of cw powers to 850 mW in Cr:LiSAF and to 650 mW in Cr:LiCAF. From the double side pumped Cr:LiCAF laser, we have also obtained ~220 fs long pulses with 5.4 nJ of pulse energy at 77 MHz repetition rate. These are the highest energy levels reported from Cr:Colquiriite so far at these repetition rates. Our findings indicate that tapered diodes in the red spectral region are likely to become the standard pump source for Cr:Colquiriite lasers in the near future. Moreover, the simplified pumping scheme might facilitate efficient commercialization of Cr:Colquiriite systems, bearing the potential to significantly boost applications of cw and femtosecond lasers in this spectral region (750-1000 nm).
我们报道了由高亮度锥形激光二极管泵浦的紧凑、低成本且高效的铬：钴酸盐激光器。这些锥形激光二极管在675nm左右提供1至1.2W的输出功率，电光转换效率约为30%。使用单个锥形二极管激光器作为泵浦源，我们分别从连续波（cw）铬：锂锶铝氟化物（Cr:LiSAF）和铬：锂钙铝氟化物（Cr:LiCAF）激光器中获得了500mW和410mW的输出功率，斜率效率分别为47%和41%。在连续波锁模运行中，在重复频率约100MHz时获得了平均功率在200mW至250mW之间的亚100飞秒脉冲序列。在用两个锥形激光二极管（从晶体的每一侧各一个）泵浦铬：钴酸盐激光器时，我们观察到铬：锂锶铝氟化物激光器的连续波功率扩展到850mW，铬：锂钙铝氟化物激光器的连续波功率扩展到650mW。从双侧泵浦的铬：锂钙铝氟化物激光器中，我们还在77MHz重复频率下获得了脉宽约220飞秒、脉冲能量为5.4nJ的脉冲。这些是目前在这些重复频率下从铬：钴酸盐激光器报道的最高能量水平。我们的研究结果表明，红色光谱区域的锥形二极管在不久的将来可能会成为铬：钴酸盐激光器的标准泵浦源。此外，简化的泵浦方案可能有助于铬：钴酸盐系统的高效商业化，具有显著推动该光谱区域（750 - 1000nm）连续波和飞秒激光器应用的潜力。
