Ultrafast Spin Noise Spectroscopy

The applicability of the experimental technique of spin noise spectroscopy is excented to the regime of very short timescales. The continous wave laser source is replaced by ultrafast laser oscillators and the time resolution is only limited by the pulse width of the laser system. By that, we can detect bandwidths of several hundred gigahertz.

The graphic on the right side shows the experimental setup with two synchronized picosecond laser oscillators (a) and a schematic measurement sequence (b).

This technique of ultrafst spin noise spectroscopy is applied to highly-n-doped bulk GaAs (see graphic below). These measurements yield a large g-factor fluctuation possibly due to the stochastic nature of dopant distribution.