Polarization-preserving confocal microscope for optical experiments in a dilution refrigerator with high magnetic field

Abstract

We present the design and operation of a fiber-based cryogenic confocal microscope. It is designed as a compact cold-finger that fits inside the bore of a superconducting magnet, and which is a modular unit that can be easily swapped between use in a dilution refrigerator and other cryostats. We aimed at application in quantum optical experiments with electron spins in semiconductors and the design has been optimized for driving with, and detection of optical fields with well-defined polarizations. This was implemented with optical access via a polarization maintaining fiber together with Voigt geometry at the cold finger, which circumvents Faraday rotations in the optical components in high magnetic fields. Our unit is versatile for use in experiments that measure photoluminescence, reflection, or transmission, as we demonstrate with a quantum optical experiment with an ensemble of donor-bound electrons in a thin GaAs film.

9 pages, 7 figures

References in corpus (7)

• Ultrafast optical rotations of electron spins in quantum dots
• Confluence of resonant laser excitation and bi-directional quantum dot nuclear spin polarization
• Ultrafast optical spin echo for electron spins in semiconductors
• Ultrafast control of donor-bound electron spins with single detuned optical pulses
• Electromagnetically Induced Transparency with an Ensemble of Donor-Bound Electron Spins in a Semiconductor
• Compact cryogenic Kerr microscope for time-resolved studies of electron spin transport in microstructures
• Towards quantum optics and entanglement with electron spin ensembles in semiconductors

Cited by in corpus (2)

• Breaking of valley degeneracy by magnetic field in monolayer MoSe2
• Stabilizing nuclear spins around semiconductor electrons via the interplay of optical coherent population trapping and dynamic nuclear polarization