Fiber-coupled spin defect magnetometry

Abstract

A magnetometer includes an electron spin defect body including a plurality of lattice point defects. A microwave field transmitter is operable to apply a microwave field to the electron spin defect body. An optical source is configured to emit input light of a first wavelength that excites the plurality of lattice point defects of the electron spin defect body from a ground state to an excited state. A first optical fiber has an input end optically coupled to the optical source and an output end. The output end is attached to a first face of the electron spin defect body and is arranged to direct the input light into the first face of the electron spin defect body. A second optical fiber has an output end and an input end. A photodetector is optically coupled to the output end of the second optical fiber.

What is claimed is: 
     
         1 . A method of manufacturing a magnetometer, comprising:
 attaching an input end of a first optical fiber to a first face of an electron spin defect body;   attaching an input end of a second optical fiber to a second face of the electron spin defect body, wherein the first face is different from the second face; and   attaching an output end of a third optical fiber to a third face of the electron spin defect body, wherein the third face is different from the first face and the second face.   
     
     
         2 . The method of  claim 1 , comprising:
 prior to attaching the input end of the second optical fiber, depositing a thin-film optical filter onto the second face of the electron spin defect body,   wherein the electron spin defect body comprises a plurality of lattice point defects, and wherein the thin-film optical filter is configured to pass photoluminescence of a second wavelength emitted by the plurality of lattice point defects and to block light of a first wavelength different from the second wavelength.   
     
     
         3 . The method of  claim 2 , wherein the first wavelength is a wavelength that excites the plurality of lattice point defects from a ground state to an excited state. 
     
     
         4 . The method of  claim 2 , wherein depositing the thin-film optical filter comprises depositing a plurality of dielectric films onto the second face. 
     
     
         5 . The method of  claim 4 , wherein at least three adjacent dielectric films of the plurality of dielectric films have alternating higher and lower refractive indices. 
     
     
         6 . The method of  claim 2 , wherein depositing the thin-film optical filter comprises depositing the thin-film optical filter using physical vapor deposition. 
     
     
         7 . The method of  claim 2 , comprising:
 coupling a photodetector to an output end of the second optical fiber; and   coupling a light source to an input end of the third optical fiber, wherein the light source is configured to emit light of the first wavelength.   
     
     
         8 . The method of  claim 2 , wherein the thin-film optical filter comprises a quarter-wave stack. 
     
     
         9 . The method of  claim 2 , comprising depositing the thin-film optical filter onto the first face of the electron spin defect body. 
     
     
         10 . The method of  claim 1 , comprising:
 depositing a thin-film optical filter onto the third face of the electron spin defect body,   wherein the electron spin defect body comprises a plurality of lattice point defects, and wherein the thin-film optical filter is configured to pass photoluminescence of a first wavelength that excites the plurality of lattice point and to block light of a second wavelength different from the first wavelength.   
     
     
         11 . The method of  claim 1 , wherein attaching the input end of the first optical fiber to the first face comprises providing adhesive onto the first face. 
     
     
         12 . The method of  claim 1 , comprising:
 attaching an output end of a fourth optical fiber to the first face of the electron spin defect body.