Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 32: Transport Properties I (mainly Spin Physics and Magnetic Fields)

HL 32.4: Talk

Tuesday, March 27, 2012, 10:45–11:00, EW 203

Ultrafast Spin Noise Spectroscopy — •Hendrik Kuhn, Fabian Berski, Jan G. Lonnemann, Petrissa Zell, Jens Hübner, and Michael Oestreich — Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstr. 2, D-30167 Hannover

Semiconductor spin noise spectroscopy (SNS) has evolved as a powerful experimental technique to explore the dynamics of carrier spins close to thermal equilibrium [1]. However, with the standard continous-wave (cw) laser probing scheme the detectable temporal spin dynamic is limited by the bandwidth of the photoreceiver. We advance SNS to detection bandwidths of several hundred gigahertz by replacing cw probe light with light from two ultrafast oscillators. The two oscillators are mode-locked with an adjustable phase which enables subsequent scanning of the temporal spin correlations via below band gap Faraday rotation. Our first measurements on highly n-doped (10¹⁷ cm⁻³) bulk GaAs perfectly demonstrate the feasibility of SNS for spin lifetimes down to the order of a few ten picoseconds without the loss of information. These measurements pave the way for future experiments where optical excitation poses an obstacle for the detection of the true spin dynamics.

[1] G. M. Müller, M. Oestreich, M. Römer and J. Hübner, Physica E 43, 569 (2010).