M. Hofmann et al., TIME-RESOLVED 4-WAVE-MIXING TECHNIQUE TO MEASURE THE ULTRAFAST COHERENT DYNAMICS IN SEMICONDUCTOR OPTICAL AMPLIFIERS, Applied physics letters, 68(23), 1996, pp. 3236-3238
A femtosecond four-wave mixing technique is used to measure the ultraf
ast coherent dynamics of the optical polarization in semiconductor opt
ical amplifiers. A heterodyne detection scheme enables us to measure a
background-free quasi-degenerate four-wave mixing signal even without
spatial separation of the pump and probe beam. First results indicate
that the polarization dephasing time close to the transparency point
is on the order of 100 fs. (C) 1996 American Institute of Physics.