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Four-wave mixing signals from extended exciton states above the mobility edge in GaAs/(Ga,Al)As multiple quantum wells

✍ Scribed by G. Bongiovanni; A. Mura; J.L. Staehli


Publisher
Elsevier Science
Year
1994
Tongue
English
Weight
210 KB
Volume
15
Category
Article
ISSN
0749-6036

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✦ Synopsis


We investigate the dependence of four-wave mixing response on the photon energy close to the fundamental exciton (X) resonance in GaAs quantum wells. We find that crosspolarised incident fields give rise to a non-linear signal which decays faster at energies below the (\mathrm{X}) line centre than above. We show that this behaviour cannot be assigned to biexciton transitions alone but rather suggests that the delocalised (\mathrm{X}) states above the mobility edge are excited off-resonantly by the laser light having slightly lower energies.