Numerical modeling of dispersive and nonlinear pulse distortions in a cr2+:znse regenerative amplifier

Cr2+:ZnSe is an attractive gain medium for ultra-short pulse generation and amplification in the mid IR spectrum at room temperature. It shows a high and broadband stimulated emission cross section coupled with a quantum yield of almost unity. A drawback is the exceptionally high nonlinear refractive index of 1.7 10-18 m2/W, which makes it susceptible to self-phase modulation effects. In amplifiers the pulse shaping effects should be calculated to make an ideal recompression possible. In the thesis work presented here, we demonstrate a numerical approach to determine both the pulse power and the dispersive broadening of a pulse, while it is propagating in a regenerative amplifier. The Frantz- Nodvik equations were extended by accounting for distortion effects from self-phase modulation and media dispersion for a Gaussian pulse. The result is a numerical code that determines the ideal extraction time and the ideal compressor dispersion for a Cr2+:ZnSe regenerative amplifier. The code has been successfully used with experimental results to estimate the stimulated emission cross section of the amplifier gain medium and the amount of chirp in the pulse. The best-fit value of the stimulated emission cross section for the Cr2+:ZnSe medium was determined to be 2.055 10-24 m2.