Diode-Pumped Nd:YAP Intracavity Optical Parametric Oscillator Emitting at 1603 nm: Influence of Energy-Transfer Upconversion

A diode-end-pumped actively Q-switched Nd:YAP laser at 1080 nm is originally designed to intracavity pump a Potassium Titanyl Phosphate KTiOPO4 (KTP)-based optical parametric oscillator for obtaining the signal wavelength at 1603 nm. Under an absorbed pump power value of 11 W, the maximum average output power at the eye-safe radiation is efficiently generated to be 1.11 W at a pulse repetition rate of 10 kHz. At a pulse repetition rate of 5 kHz, the shortest pulse duration, the largest pulse energy, and the highest peak power are found to be 2.4 ns, 190 μJ, and 67.3 kW, respectively. In addition, the influence of energy-transfer upconversion effect on the capability of power scaling of the developed Nd:YAP fundamental laser is experimentally investigated and theoretically analyzed.