Abstract

Time evolution of the optical transmission spectra in GaAs and its quantum well following femtosecond excitation shows the increase in transmission at energy close to the excitation energy. This is the spectral hole burning resulting from the initial nonthermal distribution of photoexcited carriers. This nonthermal distribution ther- malizes in a time on the order of 200 fs.^1,2 Although this fast response is very attractive, no application has been tried mainly because it is followed by rather slow response (1 ~ 100 ps) due to cooling through carrier-phonon interaction and the band filling effect.¹

© 2002 Optical Society of America