Broadband Photoconductive Sampling in Gallium Phosphide

摘要

Direct measurements of the electric field of light enable new observations oflight–matter interactions. In the near-infrared and visible spectral ranges, thistypically relies on techniques that exploit nonlinearities in gases or solids,which limits their sensitivity. Here, a method for the detection of broadbandnear-infrared fields spanning more than one octave from 110 to 220 THzbased on linear absorption in a semiconductor is demonstrated. This technique,which avoids complex vacuum setups and works under ambient conditions,employs linear photoconductive sampling (LPS) in gallium phosphide.Simulations reveal that the response function of LPS is concerned with theintensity envelope of the gate field, in contrast to electro-optic sampling,relaxing the stringent temporal requirements on the gate pulse.