Fig. 2: Detection of the microwave field vector at the nanoscale.
From: Focusing the electromagnetic field to 10−6λ for ultra-high enhancement of field-matter interaction
a The illustration of the direction of nanowire and NV center axes. b Frequency-scanning ODMR results of NV centers with four symmetry axes. c The fluorescence intensity of NV centers is enhanced due to the interaction with the Ag nanowire. The cross-section profile in the bottom is used to locate the relative position of nanowire (red points in the image). d The image of ∣BMW2∣. The cross-section profile is the integrated signal of the whole image. The solid line is the simulation with a straight line current. The value is normalized by the saturation amplitude Bsat, as defined in Supplementary Eq. (2). Error bars represent the standard error. e, f The microwave vector is revealed by comparing different projections. The result in e records the ratio of fluorescence intensity with BMW1 to the fluorescence with BMW2 and f is recorded as the ratio of fluorescence with BMW3 to fluorescence with BMW4. With a weak microwave pumping, the images of (e) and (f) approximate to the distribution of ∣BMW2∣ − ∣BMW1∣ and ∣BMW4∣ − ∣BMW3∣, respectively (see Supplementary Note 2). The scale bars in all the images are 400 nm in length. And the power of the microwave source is set to 174 μW.
