The ultrafast response of a high-reflectivity GaAsAlAs Bragg mirror to optical pumping is investigated for all-optical switching applications. Both Kerr and free carrier nonlinearities are induced with 100 fs, 780 nm pulses with a fluence of 0.64 and 0.8 kJm2. The absolute transmission of the mirror at 931 nm increases by a factor of 27 from 0.0024% to 0.065% on a picosecond time scale. These results demonstrate the potential for a high-reflectivity ultrafast switchable mirror for quantum optics and optical communication applications. A design is proposed for a structure to be pumped below the band gaps of the semiconductor mirror materials. Theoretical calculations on this structure show switching ratios up to 2200 corresponding to switching from 0.017% to 37.4% transmission.
Bibliographical noteFunding Information:
The authors thank W. Irvine and C. Simon for useful discussions. This work was supported by NSF Grant No. PHY-0334970 and DARPA Grant No. MDA972-01-1-0027. S.H. is supported by a NSF Graduate Fellowship.