Eye-safe optical parametric oscillator produces average power of 33 W
Engineers at Schwart¥Electro-Optics Aerospace Sensor Division (Orlando, FL) together with researchers at Fibertek (Herndon, VA) developed an eye-safe optical parametric oscillator (OPO) that produces an average output power of 33 W. Described in paper #CPD28 at the Conference on Lasers and Electro-Optics (CLEO `97; Baltimore MD), the device is the highest-average-power OPO demonstrated, according to researcher Mark Webb. It is based on four noncritically phase-matched potassium titanyl arsenate (KTA) crystals and pumped by a diode-pumped Nd:YAG laser producing 130-W, 100-H¥pulses at 1064 nm. After isolation and transfer optics, 107 W of pum¥light is available at the OPO input. A maximum power of 33 W is extracted at 1534.7 nm with a bandwidth of 0.6 nm. The OPO is based on a ring configuration; use of KTA minimizes thermal effects in the nonlinear crystals--due to absorption of the idler beam at 3469 nm--that are typical with more-conventional potassium titanyl phosphate crystals. The researchers expect better results when thermal management is incorporated into the OPO design.