Large optical Kerr signal of GaAs/AlAs multilayer cavity with InAs quantum dots embedded in strain-relaxed barriers
✍ Scribed by Ken Morita; Tomoya Takahashi; Toshiyuki Kanbara; Shinsuke Yano; Takuya Mukai; Takahiro Kitada; Toshiro Isu
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 275 KB
- Volume
- 42
- Category
- Article
- ISSN
- 1386-9477
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✦ Synopsis
A strong and ultrafast optical Kerr signal at 1:5 mm has been demonstrated in a GaAs/AlAs multilayer cavity containing self-assembled InAs quantum dots (QDs) embedded in strain-relaxed In 0:35 Ga 0:65 As barriers. Time-resolved optical measurements using 100 fs pulses with 100 kHz repetition rate were carried out in the various excitation powers at room temperature. Although only 2 layers of the InAs QDs were inserted in the half-wavelength ðl=2Þ cavity layer, the strongly enhanced optical Kerr signal was observed compared to that of a GaAs l=2 cavity which had no QDs, in the whole range of excitation power (1-10 mW). The signal enhancement becomes more significant with decreasing excitation power because two-photon absorption is suppressed in the l=2 cavity consisting of the 2 QD layers and strainrelaxed In 0:35 Ga 0:65 As barrier. In the low-excitation power regime of 1-2 mW, the optical Kerr signal was about 2 orders of magnitude larger than that of the GaAs l=2 cavity due to the large nonlinearity of the resonant InAs QDs.