Solid-state optical parametric oscillator with a closed-loop wavelength stabilization as a front-end of a high-power iodine laser system

In this paper, a commercially available optical parametric oscillator (OPO), tuned to the iodine laser line, is used for generation of ultra-short, ultra-high intensity pulses. Since the line is extremely narrow (20 pm FWHM), tuning of the OPO with this precision and long-term stability is an issue. An automated closed-loop control system is developed for this purpose. The principle of the stabilization is periodical re-scanning the laser peak surroundings and retuning the oscillator to the current peak position with a period of several minutes. The stabilization system is reliable and fully automated: it can operate the whole day without user interaction. In addition to the wavelength stabilization, it also monitors the temperature of the pump laser cooling water with an automatic switch-off capability, and it is also able to perform a laser switch-on procedure that consists of several steps detached by time intervals dependent on the laser warm-up progress. All these functions have been implemented using low-cost components and minimum additional electronics.