Rapid scanning of spin noise with two free running ultrafast oscillators

Abstract

We combine the scanning temporal ultrafast delay (STUD) technique with spin noise spectroscopy (SNS), which is based upon below band gap Faraday rotation to investigate the full temporal dynamics of stochastically orientated electron spins in slightly n-doped bulk GaAs. The application of STUD-SNS boosts the common technical bandwidth limitation of the electro-optic conversion in cw-SNS into the several hundred GHz regime. Numerical simulations highlight the strengths and examine the limitations of STUD-SNS.

Spin-noise spectroscopy: from proof of principle to applications

“…The efficiency of this ultrafast SNS has recently been successfully demonstrated experimentally on a heavily n-doped bulk GaAs [71,72]. The train of picosecond pulses was produced, in that experiment, by two synchronized lasers with a repetition rate of 80 MHz.…”

Electron g‐factor fluctuations in highly n‐doped GaAs at high temperatures detected by ultrafast spin noise spectroscopy

“…In practice, the probe photon energy is adjusted such that the amount of effective absorption is about equal at all temperatures. The light pulses from the two lasers are aligned along exactly coinciding propagation paths and focused with a spot radius of about m onto the sample which is mounted in a magneto‐optical cryostat with a transverse magnetic field of up to 8 T and sample temperatures between 20 and 260 K. After the laser pulses have passed through the sample, the correlation of the spin induced Faraday rotation of both time delayed laser pulses is detected by a integrating balanced photo detection setup and digitized for further analysis . The analysis of the correlated Faraday rotation signal assumes a free induction decay of the free precessing electron spins , where is the Larmor angular precession frequency.…”

“…Inset: The ionized impurity momentum scattering time extracted from magnetotransport measurements (red diamonds) and the fit according to a Brooks-Herring type transport model with phonon scattering [22]. optical cryostat with a transverse magnetic field of up to 8 T and sample temperatures between 20 and 260 K. After the laser pulses have passed through the sample, the correlation of the spin induced Faraday rotation of both time delayed laser pulses is detected by a integrating balanced photo detection setup and digitized for further analysis [7,10]. The analysis of the correlated Faraday rotation signal assumes a free induction decay of the free precessing electron spins cos(ω L t)e −t/τs , where ω L = g * μ B B/ is the Larmor angular precession frequency.…”

“…During the past decade the nearly perturbation free method of spin noise spectroscopy (SNS) has become a versatile and powerful tool for the investigation of the spin dynamics of a vast number of semiconductor systems. The applicability spans from spin coherence times of millisecond and microsecond of nuclear host spins and single holes in quantum dots over nanoseconds for the electron spin dynamics in quantum wells up to picoseconds for the very fast dynamics of free electron spins in high magnetic fields and at high temperatures . Extremely short spin dephasing times are measured by ultrafast spin noise spectroscopy (USNS) which has been proposed in 2008 and demonstrated experimentally recently .…”

Spin noise spectroscopy of quantum dot molecules

“…The accessibility of the spin noise spectroscopy technique in experiments has been limited to GHz (order of µeV) frequency scale so here we mostly concentrate on the regime of a characteristic tunneling frequency below 1 GHz. Recently, ultrafast SNS was introduced that extended the range of applications to systems with a much faster dynamics, up to hundreds of GHz 34,35 . Our results, however, can be easily extended to other frequency regimes.…”