Optical fiber spatial filtering technique for investigating carrier dynamics.

A new technique using single-mode fibers as spatial filters for probing carrier dynamics such as diffusion and recombination is introduced. Diffusion coefficients of 5.5 and 5 cm sup 2/sec are obtained for optically-excited electron-hole plasma in 1.9microns-thick In sub (0.6)Ga sub (0.4)As sub (0.85)P sub (0.15) bulk layer and in In sub (0.53)Ga sub (0.47)As/InP quantum wells with well thickness of 100angstroms, respectively.