Nonlinear absorption, SHG behavior and carrier dynamics of Nd and Pr doped GaSe single crystals

Undoped, 0.1 at% Nd and 0.1 at% Pr doped GaSe single crystals were grown by using modified Bridgman method. The nonlinear absorption (NA), second harmonic generation (SHG) and carrier dynamics of undoped, 0.1 at% Nd and 0.1 at% Pr doped GaSe single crystals have been studied by open aperture Z-scan, SHG and transmission ultrafast pump probe spectroscopy experiments, respectively. All of the studied crystals showed nonlinear absorption under 100 fs pulse duration and 1200 nm wavelength excitations. It was found that the doping of Nd3+ and Pr3+ into GaSe single crystals caused shifting of SHG signal peaks to the shorter wavelengths. However, transmission pumb-probe experiments revealed that all of the crystals showed NA signals with long lifetime under 620 nm pump and 626 nm probe excitations.