Fiber-optic magnetic-field imaging

Abstract

We demonstrate a scanning fiber-optic probe for magnetic-field imaging where nitrogen-vacancy (NV) centers are coupled to an optical fiber integrated with a two-wire microwave transmission line. The electron spin of NV centers in a diamond microcrystal attached to the tip of the fiber probe is manipulated by a frequency-modulated microwave field and is initialized by laser radiation transmitted through the optical tract of the fiber probe. The two-dimensional profile of the magnetic field is imaged with a high speed and high sensitivity using the photoluminescence spin-readout return from NV centers, captured and delivered by the same optical fiber.

Two‐photon imaging of fiber‐coupled neurons

“…When integrated with optogenetic approaches, optical fibers provide a unique toolbox , allowing the neural activity in freely behaving animals to be recorded and manipulated using optical methods. Optical fibers combined with diamond electron‐spin‐resonance sensors enable precisely localized laser heating and unique temperature measurements with a single‐cell resolution , promoting the use of thermosensitive genetically encodable channels as powerful tools for both large‐scale and single‐cell neuromodulation.…”

Room-temperature magnetic gradiometry with fiber-coupled nitrogen-vacancy centers in diamond

“…While the highest sensitivities of NV-diamond-based magnetic-field sensing and gradiometry have been achieved using confocal microscopy [10,11], optical fibers have been recently shown [11][12][13] to offer a missing link for a practical implementation of NVdiamond-based sensing in a variety of environments, including magnetic-field and temperature measurements in biological systems.…”

Microwave-induced thermogenetic activation of single cells

“…[21][22][23] This laser radiation couples the 3 A ground electronic state to the 3 E excited state, giving rise to photoluminescence (PL), featuring a characteristic zero-phonon line, which is observed at approximately 637 nm at room temperature against a broad phonon-sideband line, stretching down to 800 nm. Photoluminescence emitted by laser-initialized NV centers within the 630-800-nm wavelength range is collected by the same optical fiber, 18,19 and is transmitted through this fiber to the detection system, consisting of a silicon photodiode, a low-noise preamplifier, and a lock-in amplifier (Fig. 1).…”

“…For the highest sensitivity and highest speed of local temperature measurements in a cell culture, frequency-modulated microwave spin excitation in NV centers was combined with properly optimized differential lock-in detection. 19,24 In a calibration experiment, the fiber probe was placed inside a thermostat with a precisely controlled temperature along with a thermocouple, providing an accuracy of temperature measurements higher than 0.1 C. Figure 2(b) displays the magnetic-resonance frequency X s measured as a function of the temperature inside the thermostat according to thermocouple readings. As can be seen from this plot, a linear function with a slope dX s /dT % À76.3 6 0.2 kHz/K (solid line in Fig.…”