System and method for suppressing technical noise in absorption-based laser …
US20260056270A1
Abstract
A method of accounting for signal noise in a hybrid laser system is described. The hybrid laser system includes a high reflectivity mirror, a nitrogen-vacancy center diamond, a microwave antenna, a dichroic mirror, a half-vertical cavity surface emitting laser (VCSEL), a birefringent filter, an etalon, an output coupler, and a photodiode. The method includes: measuring a shift in a left-hand side frequency as related to an optically detected magnetic resonance (ODMR) frequency peak of an ODMR signal; measuring a shift in a right-hand side frequency as related to the ODMR frequency peak; normalizing the shift in the left-hand side frequency; normalizing the shift in the right-hand side frequency; and comparing the shift in the left-hand side frequency to the shift in the right-hand side frequency to determine a technical noise associated with the ODMR signal.
Description (excerpt)
CROSS REFERENCE TO RELATED APPLICATIONS Pursuant to 37 C.F.R. § 1.78(a)(4), this application claims the benefit of and priority to prior filed co-pending Provisional Application No. 63/685,526, filed Aug. 21, 2024, which is expressly incorporated herein by reference in its entirety. RIGHTS OF THE GOVERNMENT The invention described herein may be manufactured and used by or for the Government of the United States for all governmental purposes without the payment of any royalty. FIELD OF THE INVENTION The present invention relates generally to magnetometry and, more particularly, to magnetometry using NV center diamonds and laser systems. BACKGROUND OF THE INVENTION Nitrogen-vacancy (NV) centers have considerable promise for use as magnetometers, however miniaturization is limited by inefficient collection of the photoluminescence used to read out magnetic fields. Laser threshold magnetometry (LTM) enables efficient signal collection, providing a path towards compact high sensitivity magnetometry. Currently, demonstrations reveal technical noise associated with mechanical vibrations, component thermal fluctuations thermal atmospheric flows, and pump noise. These various noises all lead to sensitivities that are order(s) of magnitude higher than the photon shot-noise limit which defines the lowest limit of possible sensitivity for a given sensor. Therefore the ability to separate signal variations which allow for separation of signals of interest (resulting from magnetic field variations) from laser noise would be beneficial. SUMMARY OF THE INVENTION The present invention overcomes one or more of the foregoing problems and other shortcomings, drawbacks, and challenges of optically-detected magnetic resonance (ODMR) readout of NV diamond magnetometry. While the invention will be described in connection with certain embodiments, it will be understood that the invention is not limited to these embodiments. To the contrary, this invention includes all alternatives, modifications, and equivalents as may be included within the spirit and scope of the present invention. According to one embodiment of the present invention, a method of accounting for signal noise in a hybrid laser system is described. The hybrid laser system includes a high reflectivity mirror, a nitrogen-vacancy center diamond, a microwave antenna, a dichroic mirror, a half-vertical cavity surface emitting laser (VCSEL), a birefringent filter, an etalon, an output coupler, and a photodiode. The method includes: measuring a shift in a left-hand side frequency as related to an optically detected magnetic resonance (ODMR) frequency peak of an ODMR signal; measuring a shift in a right-hand side frequency as related to the ODMR frequency peak; normalizing the shift in the left-hand side frequency; normalizing the shift in the right-hand side frequency; and comparing the shift in the left-hand side frequency to the shift in the right-hand side frequency to determine a technical noise associated with the ODMR signal. In another embodiment, a method of retrieving signals at two radiofrequencies on either side of a peak frequency includes steps of: modulate a left-hand side frequency at a left-hand low lock-in modulation frequency and retrieve the modulated left-hand side frequency using a first lock-in amplifier; modulate a right-hand side frequency at a right-hand low lock-in modulation frequency and retrieve the modulated right-hand side frequency using a second lock-in amplifier; and subtract the modulated left-hand side frequency from the right-hand side frequency using a single lock-in amplifier using a signal modulation frequency to the left-hand side frequency and the right-hand side frequency based on the left-hand side frequency and the right-hand side frequency being 180 degrees out of phase as compared to one another. In yet another embodiment, a method of suppressing noise and accounting for thermal drift in a hybrid laser system includes: monitoring a first frequency peak and a second frequency peak on either of: 1) a low-frequency side or, 2) a high-frequency side of an average frequency peak; modulating the first frequency peak at a first low lock-in frequency and retrieve the modulated first frequency peak with a first lock-in amplifier; modulating the second frequency peak at a second low lock-in frequency and retrieve the modulated second frequency peak with a second lock-in amplifier; subtracting the modulated, retrieved second frequency peak from the modulated, retrieved first frequency peak to account for thermal drift in the hybrid laser system. Additional objects, advantages, and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the followi
Filing details
- Inventors
- Robert Bedford
- Assignee
- Government Of The United States As Represented By The Secretary Of The Air …
- Filed
- Aug 7, 2025
- Granted
- Application pending
Bibliographic data and excerpted text sourced from Google Patents (public record) as part of IP TechMatch's current-filings monitor. This filing is not part of the 2019 historical archive. For the authoritative full text, drawings, and legal status, see the source links above or consult USPTO records directly.