Development of a Modular Optically Detected Magnetic Resonance Setup for Optical Experiments in a Variable Temperature Insert

TL;DR

This paper presents a modular ODMR setup compatible with a helium cryostat for optical experiments at variable temperatures, enabling NV center studies in cryogenic environments.

Contribution

A novel, adaptable ODMR system designed for integration with standard cryogenic setups, allowing optical and magnetic measurements at low temperatures.

Findings

Successful measurement of temperature-dependent resonance signals.

Detection of magnetic transitions in SrRuO3.

Maintained optical alignment over a two-meter path.

Abstract

We developed an optically detected magnetic resonance (ODMR) setup designed for compatibility with a widely used, commercially available helium bath cryostat equipped with a variable temperature insert. The optical path extends nearly two meters, spanning the full length of the cryostat insert, enabling excitation of the nitrogen-vacancy (NV) centers and detection of the resulting fluorescence from outside the cryostat. The setup preserves optical alignment and beam quality along this extended path allowing integration into existing cryogenic systems without significant modifications. We demonstrate the setup's performance by measuring the temperature dependence of the resonance signal and its behavior under small applied magnetic fields, as well as the magnetic transition of a SrRuO$_3$ sample, thereby showcasing the feasibility of NV magnetometry on a sample in constrained cryogenic environments.