Excitonic optical nonlinearity induced by internal field screening in (211) oriented strained-layer superlattices
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (US)
- ECE, University of California, Santa Barbara, California 93106 (USA)
The nonlinear optical properties of a new class of strained-layer superlattices (intrinsic Stark effect superlattices) have been investigated. Specifically, we have compared the nonlinear transmission of Ga{sub 1{minus}{ital x}}In{sub {ital x}}As-GaAs strained-layer superlattices grown along the (211) axis to identical superlattices grown along the (100) axis, and found that the optical nonlinearity in the (211) sample is about one order of magnitude greater than in the (100) sample. A blue shift of the exciton resonance and an increase in the exciton absorption strength in the (211) sample with increasing light intensity was observed (attributed to screening of the intrinsic Stark effect fields by photogenerated carriers), resulting in the stronger optical nonlinearity. The maximum of the nonlinear absorption index, {vert bar}{alpha}{sub 2}{vert bar}, in the (211) sample was 54 cm/W ({vert bar}Im {chi}{sup 3}{vert bar}=0.33 esu) whereas in the (100) sample the maximum of {vert bar}{alpha}{sub 2}{vert bar} was 6.9 cm/W ({vert bar}Im {chi}{sup 3}{vert bar}=0.042 esu). The measured carrier recovery time in both samples was 2 ns.
- OSTI ID:
- 5636826
- Journal Information:
- Applied Physics Letters; (USA), Vol. 58:7; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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