Transient Absorption of CdSiP2 and ZnGeP2

Hero Endo


Transient absorption spectroscopy was used to observe and study the dynamic behavior of light and matter interaction for semiconducting nonlinear optical crystals, CdSiP2 and ZnGeP2. A mode locked Ti Sapphire laser amplifier generating pulses at a central wavelength of 800 nm with a pulse width of 100 fs at a 1 kHz repetition rate, and an average power of 3.5 W, were split into two beams, pump and probe. The pump beam was given larger power than that of the probe to excite the carriers within the sample. The probe, which has negligible effect on the excited state to the sample observes the change in carrier concentration. After carefully aligning the beams and adjusting the power, data were collected using a computer program which plots intensity vs. time. The collected data were normalized and plotted onto a graph with exponential decay according to the rate equation. It was found that both samples have three exponential terms for higher power, indicating more complex dynamics happening in these samples.