Application of a GaN photodiode for autocorrelation measurements of visible femtosecond pulses

Summary form only given. In a number of recent papers the use of two-photon absorption in semiconductor devices was demonstrated for performing autocorrelation measurements of femtosecond pulses. Such devices have a number of advantages over a second-harmonic crystal/detector combination. The bandgap of the materials associated with these photosensors determines the wavelength region where the two-photon absorption occurs. For example, GaAsP photodiodes are well-suited for near infrared and SiC photodiodes for the visible-red optical bands. In order to characterize pulses in the blue-violet part or the ultraviolet part of the spectrum, one requires materials with larger bandgaps. The ultraviolet optical switch based on two-photon conductivity in fused silica was studied and its performance was characterized at 267 nm. We characterize the performance of the GaN p-i-n photodiode as a nonlinear photodetector for autocorrelation measurements of femtosecond pulses at 410 nm.