Direct observation of intersubband relaxation dynamics and application to subpicosecond all-optical modulation

Author

Asano, Takashi ; Yoshizawa, Shin ; Noda, Susumu

Author_Institution

Dept. of Electron. Sci. & Eng., Kyoto Univ., Japan

fYear

2001

fDate

2001

Firstpage

513

Lastpage

516

Abstract

An improved all-optical modulation scheme based on intersubband transition in n-doped quantum well is proposed, which utilizes electron population dynamics in the 2nd conduction subband instead of the 1st subband utilized in the previous scheme. The modulation characteristics and the intersubband relaxation dynamics are investigated by white-light pump-probe spectroscopy in GaAs/AlGaAs quantum wells. The response time of the modulation is found to be ~0.4 ps, which is much shorter than theoretically expected value of ~1 ps. It is also found that the population relaxation time in the 1st subband is longer than that in the 2nd conduction subband as a factor of 10. The discrepancies are attributed to the existence of the relaxation path via subbands in L valley that has very large density of states

Keywords

III-V semiconductors; aluminium compounds; gallium arsenide; high-speed optical techniques; optical modulation; semiconductor quantum wells; time resolved spectra; GaAs-AlGaAs; GaAs/AlGaAs quantum well; L valley; conduction subband; density of states; electron population dynamics; intersubband relaxation dynamics; intersubband transition; subpicosecond all-optical modulation; white-light pump-probe spectroscopy; Delay; Electrons; Gallium arsenide; Intensity modulation; Optical modulation; Optical pumping; Optical scattering; Resonance light scattering; Substrates; Ultrafast optics;

fLanguage

English

Publisher

ieee

Conference_Titel

Indium Phosphide and Related Materials, 2001. IPRM. IEEE International Conference On

Conference_Location

Nara

ISSN

1092-8669

Print_ISBN

0-7803-6700-6

Type

conf

DOI

10.1109/ICIPRM.2001.929193

Filename

929193