Wide - Field Optical Microscopy of Microwave Fields Using Nitrogen - Vacancy Centers in

Abstract

been investigated. [ 33–38 ] Pulsed laser sequences [ 33–37 ] were used to measure Rabi oscillations between different spin ground states, and scanning probe techniques [ 37 ] were used to achieve nanoscale resolution. For many practical applications, however, wide fi eld imaging and a simple experimental procedure are benefi cial. To accomplish this, we opt for continuous wave laser excitation [ 35,38 ] to measure the spin populations of NVs in the presence of microwave fi elds using a conventional inverted microscope. In this way, we demonstrate wide-fi eld imaging of microwave fi elds over a 200 × 200 μm 2 area with submicrometer spatial resolution, and spectral analysis of the microwave fi eld with a resolution bandwidth of 460 kHz (i.e., the linewidth of NV). Minimum detectable microwave power of tens of nanowatts and a large dynamic range of over 33 dB in microwave power is obtained. Importantly, by using a bias magnetic fi eld we could control the microwave frequency that NV centers are sensitive to—via Zeeman effect—over a frequency range of 170 MHz (potentially up to 100 GHz (ref. [ 35 ] )). In addition, we demonstrate a high frequency sensitivity of 2.5 kHz Hz −1/2 for a single frequency-modulated microwave signal detection. A schematic of our apparatus is depicted in Figure 1 a (see Figure S1 in the Supporting Information for the detailed experimental setup). A diamond chip containing a thin layer of NV centers with NV density of 3–4 ppm and linewidth of 460 kHz (see the Experimental Section for detail) contributes to spatial and spectral resolutions and signal-to-noise ratio. This diamond chip is closely placed on top of a microwave circuit under investigation, allowing near fi eld imaging of microwave fi elds. An inverted optical microscope is used to deliver green (532nm) laser probe light and NV fl uorescence (600–750 nm) is collected through the same objective. The collected light is fi ltered and focused onto an electron-multiplying charge coupled device (EM-CCD) for imaging. An electromagnet is used to provide a bias DC magnetic fi eld B 0 that controls the frequency splitting ν 0 between the NV’s spin 0 ground state |0> g and the spin –1 ground state |–1> g , according to D B 0 0 0 ν γ = − . Here, D 2.87 GHz 0 = is the crystal fi eld splitting and (2 ) 28 MHz mT 1 γ π = − is the gyromagnetic ratio. For simplicity, in this work we align B 0 with one of possible NV orientations and focus on states |–1> g and |0> g , only. The spectral analysis of an unknown microwave fi eld is accomplished by scanning ν 0 over a wide frequency range, by sweeping a voltage applied to the electromagnet, while monitoring the NV fl uorescence intensity. As illustrated in Figure 1 b, when the microwave frequency f RF is resonant with ν 0 , the NV is driven from |0> g to |–1> g by the microwave magnetic fi eld with polarization perpendicular Wide-Field Optical Microscopy of Microwave Fields Using Nitrogen-Vacancy Centers in Diamonds

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Cite this paper

@inproceedings{Linbo2016WideF, title={Wide - Field Optical Microscopy of Microwave Fields Using Nitrogen - Vacancy Centers in}, author={Linbo and Ruishan Liu and Mian Zhang and Anna V . Shneidman and Xavier Audier and Matthew L. Markham and Harpreet Dhillon and Daniel J. Twitchen and Yun Xiao and Marko Lon{\vc}ar}, year={2016} }