Probe Power Density Dependence in Nitrogen Vacancy Diamond Magnetometry

Date of Award

5-9-2026

Degree Name

M.S. in Electro-Optics

Department

Department of Electro-Optics and Photonics

Advisor/Chair

Andrew Sarangan

Abstract

This thesis investigates the relationship between optically detected magnetic resonance (ODMR) contrast and magnetic sensitivity in nitrogen-vacancy (NV) diamond magnetometry as probe beam power density increases. High-sensitivity magnetometry is a critical enabling technology for navigation in GPS-denied environments, utilizing crustal magnetic anomalies as a stable positioning reference. Employing a Fabry-Perot cavity-enhanced architecture, a 1042 nm probe laser was phase-modulated and modeled in a Pound-Drever-Hall locked configuration with an NV-doped diamond sample under 532 nm pumping. ODMR spectra were simulated across a range of beam geometries to quantify how localized optical intensity influences resonance parameters. To support the transition toward integrated quantum sensors, this work also details the design of silicon nitride $Si_3N_4$ adiabatic tapers and guided-mode configurations for on-chip ring resonators. Results indicate that while increasing probe power density significantly enhances ODMR contrast, it introduces measurable power broadening that increases the resonance linewidth. However, within the investigated power regime, the system does not reach full transition saturation, allowing for continued sensitivity improvements driven by photon shot noise reduction. This study investigates the optimal balance between intensity-induced broadening and signal enhancement, providing a framework for maximizing the performance of compact, cavity-enhanced NV magnetometers.

Keywords

Optics, Physics, Quantum Physics

Comments

OCLC No. 1591829965

Rights Statement

Copyright 2026, author.

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