Investigation of sum frequency generation using chirped pulses

During this work, optical parametric oscillator, which has tunable wavelength channel (700-900nm) and non-tunable (1026nm) channels, was used. Using chirped pulses from both channels, sum frequency pulses were generated and studied. System also consists of dispersion control elements such as: prism compressor and N-SF66 and ZnSe plates system. It was showed, that by using prism compressor, tunable channel pulse durations were changed from 300fs to 1600fs by changing GDD values from -15000fs^2 to -63000fs^2. By generating sum frequency pulses while using opposite sign phase modulated interacting pulses in our system, sum frequency pulse spectral width was compressed up to 3 times, ΔvΔt=3.2 . If we wanted to generate pulses with narrower spectrum, system had to be optimized by changing interacting pulse’s parameters accordingly. Efficiency of sum frequency generation in this system was 5-10%. Efficiency was limited by second harmonic pulses generating from both channel‘s pulses. Additional conversion efficiency limitation was noticed because of the GDD - when ±60000fs^2 GDD was applied for both of interacting pulses, sum frequency pulse‘s power decreased by 50%. It was also noticed, that it is possible to tune generated sum frequency pulse‘s central wavelength by 1.5nm by controlling delay between interacting pulses. However, power of sum frequency pulse decreased by factor of 3, because of poor intensity overlap between interacting pulses