Spin relaxation and all optical polarization switching at 1.52 micrometres in InGaAs(P)/InGaAsP multiple quantum wells

Abstract

The spin relaxation times of electrons in InGaAs(P)/InGaAsP multiple quantum wells have been directly measured as a function of well width using an ultrashort pulse colour centre laser. The times measured range from 20 to 5 ps, considerably faster than previously determined in GaAs quantum wells. In addition, a fast, all-optical polarization switch based on a spin-sensitive optical nonlinearity is demonstrated at a wavelength of 1.52 µm. This operating wavelength and the observed switch recovery time of 5.5 ps make it a potentially useful element for future all-optical soliton communication systems.

Spin-relaxation suppression by compensation of bulk and structural inversion asymmetries in [111]-oriented quantum wells

“…1 can nearly vanish is significant because it is essentially isotropic. 2 A number of experimental measurements in nominally symmetric InGaAs/ InP and InGaAs/ InAlAs QWs grown on ͓001͔ substrates have been published, [20][21][22][23][24] with room temperature spin-relaxation time s ranging from a few picoseconds to a few hundreds of picoseconds. 2 shows semilog polar plots of the spin splitting in the AQW.…”

Subpicosecond spin relaxation in GaAsSb multiple quantum wells

“…1 Such switches have been demonstrated at a wavelength of 800 nm using GaAs quantum wells and spin-relaxation times of Ͼ7 ps. [2][3][4] Because of the possible relevance to optical communications technology, InGaAs͑P͒ quantum wells with a band gap near 1.55 m have also been investigated 1,5 and typical spin-relaxation times are Ͼ5 ps.…”

Spin dynamics in semiconductors

“…The quantum well width dependence of spin relaxation was investigated in Refs. [592,602,603,614,[616][617][618][619]. All these studies were performed at room temperature in the nondegenerate regime.…”