Hybrid nanophotonic-nanomagnonic SiC-YiG quantum sensor: I/theoretical design and properties

Abstract

Here I present the theory of a new hybrid paramagnetic-ferrimagnetic SiC-YiG quantum sensor. It is designed to allow sub-nanoscale single external spin sensitivity optically detected pulsed electron electron double resonance spectroscopy, using an X band pulsed EPR spectrometer and an optical fiber. The sensor contains one single V2 negatively charged silicon vacancy color center in 4H-SiC, whose photoluminescence is waveguided by a 4H-SiC nanophotonic structure towards an optical fiber. This V2 spin probe is created by ion implantation at a depth of few nanometers below the surface, determined by optically detected paramagnetic resonance under the strong magnetic field gradient of a YiG ferrimagnetic nanostripe located on the back-side of the nanophotonic structure. This gradient also allow the study, slice by slice at nanoscale, of the target paramagnetic sample. The fabrication process of this quantum sensor, its magnetic and optical properties, its external spins sensing properties in a structural biology context, and its integration to a standard commercially available pulsed EPR spectrometer are all presented here.

Hybrid nanophotonic-nanomagnonic SiC-YiG quantum sensor: II/dark spins quantum sensing with V2 spins and fiber based OP-PELDOR/ODMR

“…Integrating an optical fiber, an optical coupler and the SiC device inside a standard EPR tube, itself inserted inside the standard 3D microwave resonator of the worldwide used commercial pulsed EPR spectrometer is, in a sense, equivalent to introducing part of the optical setup inside the 3D microwave resonator. As it was theoretically demonstrated previously [1], the use of the proposed nanophotonic-nanomagnonic SiC-YiG quantum device will further allow to achieve spatially selective and highly efficient collection of the photoluminescence of the single color center in SiC, because the exciting light pulse and the photoluminescence photons will be efficiently waveguided on the nanophotonic SiC chip proposed, between the optical fiber and the V2 color center spin probe [1]. This is the opposite approach to previous ones with single color center sensitivity [4,12,13], where, in a sense, the home built pulsed EPR spectrometer, in the form of a flat microwave chip device, was introduced inside the optical confocal microscope, at the price of building a homemade pulsed EPR spectrometer compatible with the optical confocal microscope, with the appropriate cryogenic and software environment, all requiring lots of time, money and appropriate engineering skills, if one wishes to reach the capabilities offered by modern state of art pulsed EPR spectrometers.…”

“…I recently presented the theory [1] of a new SiC-YiG quantum sensor and the associated state of art optically detected pulsed double electron electron spin resonance spectroscopy (OD-PELDOR), allowing sub-nanoscale single external spin sensing. This new methodology requires only the use of a standard X band pulsed EPR spectrometer [2], as well as an optical fiber and a new SiC-YiG quantum sensor [1], in which a single V2 silicon vacancy color center in 4H-SiC [3][4][5][6][7] is used as the spin probe. The single optical fiber and the quantum sensor can be both introduced in a standard EPR tube, thus requiring a minimal experimental development [1] around the commercial cw/pulsed EPR spectrometer widely used worldwide.…”

“…This new methodology requires only the use of a standard X band pulsed EPR spectrometer [2], as well as an optical fiber and a new SiC-YiG quantum sensor [1], in which a single V2 silicon vacancy color center in 4H-SiC [3][4][5][6][7] is used as the spin probe. The single optical fiber and the quantum sensor can be both introduced in a standard EPR tube, thus requiring a minimal experimental development [1] around the commercial cw/pulsed EPR spectrometer widely used worldwide. This pulsed EPR spectrometer was developed by microwave engineers over decades and is still under development nowdays.…”

“…Here I demonstrate this, using a commercial pulsed EPR/pulsed ELDOR X band spectrometer and an optical fiber. This is a second key experiment towards the development of the new SiC-YiG quantum sensor and its related nanoscale ultra-sensitive ODPELDOR methodology, because PELDOR spectroscopy at two different microwave frequencies and single fiber based optical pumping are two key experimental tools to combine in this new proposed methodology [1].…”

“…The whole experimental setup I used corresponds to the one described in Figure 2 of my previous theoretical work [1], the coupler between the SiC sample and the optical fiber being here a GRIN microlens. The optical fiber, the GRIN microlens and the bulk HPSI 4H-SiC sample containing residual V2 spins are all introduced in an EPR tube, which itself is inserted inside the pulsed EPR/ELDOR resonator, a flexline resonator from Bruker (MD5 or MS3 depending on experiments).…”