  Localized electronic spins in solid-state environments form versatile and
robust platforms for quantum sensing, metrology and quantum information
processing. With optically detected magnetic resonance (ODMR), it is possible
to prepare and readout highly coherent spin systems, up to room temperature,
with orders of magnitude enhanced sensitivities and spatial resolutions
compared to induction-based techniques, allowing for single spin manipulations.
While ODMR was first observed in organic molecules, many other systems have
since then been identified. Among them is the nitrogen-vacancy (NV) center in
diamond, which is used both as a nanoscale quantum sensor for external fields
and as a spin qubit. Other systems permitting ODMR are rare earth ions used as
quantum memories and many other color centers trapped in bulk or 2-dimensional
host materials. In order to allow the broadest possible community of
researchers and engineers to investigate and develop novel ODMR-based materials
and applications, we review here the setting up of ODMR experiments using
commercially available hardware. We also present in detail the dedicated
collaborative open-source interface named Qudi and describe the features we
added to speed-up data acquisition, relax instrument requirements and extend
its applicability to ensemble measurements. Covering both hardware and software
development, this article aims to steepen the learning curve of newcomers in
ODMR from a variety of scientific backgrounds, optimize the experimental
development time, preempt the common measurement pitfalls, and provide an
efficient, portable and collaborative interface to implement innovative
experiments.
