An Integrated Widefield Probe for Practical Diamond Nitrogen-Vacancy Microscopy

Abstract

The widefield diamond nitrogen-vacancy (NV) microscope is a powerful instrument for imaging magnetic fields. However, a key limitation impeding its wider adoption is its complex operation, in part due to the difficulty of precisely interfacing the sensor and sample to achieve optimum spatial resolution. Here we demonstrate a solution to this interfacing problem that is both practical and reliably minimizes NV-sample standoff. We built a compact widefield NV microscope which incorporates an integrated widefield diamond probe with full position and angular control, and developed a systematic alignment procedure based on optical interference fringes. Using this platform, we imaged an ultrathin (1 nm) magnetic film test sample, and conducted a detailed study of the spatial resolution. We reproducibly achieved an estimated NV-sample standoff (and hence spatial resolution) of at most ∼ 2 µm across a ∼ 0.5 mm field of view. Guided by these results, we suggest future improvements for approaching the optical diffraction limit. This work is a step towards realizing a widefield NV microscope suitable for routine high-throughput mapping of magnetic fields.

Imaging current paths in silicon photovoltaic devices with a quantum diamond microscope

“…Compared to other methods to realize MCI, this platform offers generally superior field sensitivity for imaging at micrometer scales [14], is relatively simple to implement and robust to operate given the absence of moving parts, and is not subject to optical shading. The accessibility of the technique can be further improved by automating the positioning of the diamond sensor near the device's surface [33], alleviating the need for the user to handle the diamond directly. The size of typical diamond substrates and laser intensity requirements limits the field of view to a few millimeters at most [22], although imaging over centimeters is in principle achievable via image stitching.…”

“…However, thin-film PV devices generally feature much shorter diffusion lengths (≈ 1 µm) compared to c-Si, as well as geometrically complex electrode structures [37,38], and as such will require the spatial resolution to be optimized. QDM experiments with this goal would need to prioritize achieving at least diffraction limited resolution (≈ 500 nm), requiring careful reduction of standoffs [33] or perhaps super-resolution techniques [39]. Finally, while interdigitated back-contact devices are an obvious target with their predominantly lateral transport, sandwich-type devices with contacts on either side of the perovskite film could also serve as an interesting test system to explore current inversion methods adapted to this regime, where transport occurs primarily in the vertical direction (J z ; see Appendix E).…”