Oscillations associated with interband optical transitions on Landau l
evels have been obtained in samples of single crystal Bi consisting of
two plane-parallel slabs separated by a gap of 2-3 times the waveleng
th of radiation (10.6 mu m) introduced into the gap in pulsed magnetic
fields at T=80 K. The possibility is demonstrated of using these osci
llations to obtain IR spectra of processes lasting less than 10(-4) s.
(C) 1996 American Institute of Physics.