Integrated Magnetometry Platform with Stackable Waveguide-Assisted Detection Channels for Sensing Arrays

Abstract

The negatively-charged NV − -center in diamond has shown great success in nanoscale, highsensitivity magnetometry. Efficient fluorescence detection is crucial for improving the sensitivity. Furthermore, integrated devices enable practicable sensors. Here, we present a novel architecture which allows us to create NV − -centers a few nanometers below the diamond surface, and at the same time in the mode field maximum of femtosecond-laser-written type-II waveguides. We experimentally verify the coupling efficiency, showcase the detection of magnetic resonance signals through the waveguides and perform first proof-of-principle experiments in magnetic field and temperature sensing. The sensing task can be operated via the waveguide without direct light illumination through the sample, which marks an important step for magnetometry in biological systems which are fragile to light. In the future, our approach will enable the development of two-dimensional sensing arrays facilitating spatially and temporally correlated magnetometry.

On-chip single-photon subtraction by individual silicon vacancy centers in a laser-written diamond waveguide

“…The relative intensities found for the PLE measurement in transmission and reflection, compare to fig. 3 (b), lead to a relative coupling efficiency of η rel = 0.115 ± 0.007 and are in agreement with the results of a previous study [25].…”

“…These walls are created by femtosecond laser-writing [20,33,34] and are optimized for a transmission wavelength of 738nm, corresponding to the zero phonon line (ZPL) wavelength of the SiV − center. Similar to previous experiments with NV − centers [25], the defect centers are created by shallow ion implantation into the front facet of the waveguides (see fig. 1 (a)) [35].…”

“…The laser-written waveguides can be adapted to a broad wavelength range and extended to more complex photonic structures such as beamsplitters [21], Braggmirrors [22] and 3D structures [21,23]. To functionalize the platform, NV − centers have been created on demand by laser iradiation [24] or by shallow ion implantation into the front facet [25]. However, the intrinsic cooperativity of laser-written photonics is still low owing to the relatively large mode-field diameter, therefore prohibiting non-linear effects on the single photon single emitter level.…”

Quantum technologies in diamond enabled by laser processing

“…A first demonstration of a device combining laser written waveguides arrays with shallow ion implanted NV À center ensembles for temperature and magnetic field sensing has recently been reported by Hoese et al 64 Such a system combines the sensing capabilities of NV À ensembles with the photon routing properties of optical waveguides, separating the optical access to the NV centers from the object to be sensed and allowing noninvasive field detection from biological and chemical samples [Fig. 4(a)].…”

Laser-written vapor cells for chip-scale atomic sensing and spectroscopy

“…Thanks to its unique 3D structuring capabilities, FLW has enabled many innovative geometries for the fabrication of integrated photonic devices like directional couplers and Y-splitters [5], complex multipaths interferometers [6], 3D waveguide lattices [7,8], polarization rotators [9,10], and Bragg reflectors [11]. This versatility, in addition to low-cost and rapid prototyping, has allowed the fabrication of FLW-based devices for waveguide-assisted applications in several fields like astrophotonics [12], telecommunications [13], high-order harmonic generation in gases [14], optical [15,16] and NV center-based sensing [17]. Most notably, FLW-based optofluidic and microfluidic lab-on-chip techniques, in which three-dimensional microchannels and optical waveguides are monolitically integrated within the same substrate, [18,19] are now a mature technology used world-wide for chemical analysis [20,21], biosensors [22] and single-cell processing tools [23][24][25].…”