Compact, thermally boosted direct pumped Nd:MgO:PPLN, mid-infrared self-optical parametric oscillator

A compact mid-infrared self-optical parametric oscillator (SOPO) based on thermally boosted direct pumped (4I9/ 2 Z3 -> 4F3/2 R2) is realized for the first time (to our knowledge). The SOPO that measures only 60 mm is achieved. When the absorbed pump power is 28.4 W, the maximum average power of 1.59 W is obtained, corresponding to a pulse repetition rate of 119.57 kHz and pulse width of 6.71 ns, respectively. The wavelength of the SOPO is controlled at 3834.3 nm within the entire pump region by adjusting the TEC's cooling temperature, leveraging the reduction in thermal effects achieved through the thermally boosted direct pumped technique. Furthermore, the SOPO wavelength could be tuned from 3816.7 to 3846.1 nm. This work obtains the highest average power in the compact mid-infrared SOPO and provides an efficient method to generate mid-infrared pulsed laser, which has important applications in far-infrared laser generation, gas detection, and laser medicine.