Second Harmonic Generation Optimization under Limited Power Density of Fundamental Radiation: Part 1

The process of second harmonic generation (SHG) of laser radiation in a BBO crystal is theoretically studied with the aim of determining optimal values of focusing and wave detuning parameters providing maximal SHG efficiency. This optimization problem is solved with an additional condition, that is, the maximal radiation power density should not exceed an a priori specified value. No restrictions are posed on the radiation power. The study consists of two parts. In the first part (this work), the influence of this additional condition on the process and results of solving the optimization problem is studied with the use of the preset field approximation. Due to the additional condition, optimal focusing and wave detuning parameters become dependent on the radiation power, but the algorithm for solving the problem becomes noticeably simpler, which significantly (about an order of magnitude) reduces the computation time.