Nanopositioning of a diamond nanocrystal containing a single nitrogen-vacancy defect center
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(a) Schematic of the nanomanipulator. The coarse stage can be moved in three dimensions by Attocube piezo steppers (range of 3 mm, smallest step size of 25 nm). A sharp, chemically etched tungsten tip is mounted on the piezo fine stage (range of , smallest step size of subnanometer) which can also be moved in three dimensions. Both stages are controlled by an analog joystick, allowing for accurate adjustment of their positions. [(b) and (c)] SEM images showing a nanocrystal being attached to the tip (shaded blue) (b) and subsequently being lifted from the substrate by retraction of the tip (c). (d) SEM image of four diamond nanocrystals that were subsequently picked up and positioned to form a line. [(e) and (f)] SEM images showing a nanocrystal (shaded pink) first attached to the tip (e), then being positioned onto another nanocrystal (f).
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Identifying and positioning a single NV center. (a) PL image of part of the sample around a gold marker. The bright spot in the lower left corner is verified to be a single NV center in (b) and (c). (b) Autocorrelation function of photon detection events, showing an antibunching dip below 0.5 (Ref. 14). The solid line is a fit based on a three-level model (Ref. 14). The dotted line indicates the independently measured contribution of background fluorescence. (c) PL spectrum of the NV center showing the characteristic ZPL around 637 nm (Ref. 16). Red (blue) data is taken before (after) positioning (Ref. 25). (d) SEM image of the same area as in (a). (e) Zoom in on the white box in (d), with the arrow pointing to the nanocrystal containing the NV center. The faint white spots next to it are markings made by focusing the laser onto a spot for 2 min at a power of 10 mW to facilitate identification of the NV-containing nanocrystal. The contrast difference is presumably due to local oxidation or evaporation of the Cr film. The tip is visible on the left.
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Optical and spin characterization of a single NV center after positioning. (a) PL image of the same area as in Fig. 2(a) (Ref. 25). The NV-containing crystal has been moved from the lower left to the upper right corner. (b) Measurement of as in Fig. 2(b), showing an antibunching dip below 0.5. (c) ODMR and (d) coherent oscillations of the NV center electron spin. The ODMR splitting is due to a stray magnetic field . Microwaves are applied through a diameter wire that is located in close proximity to the NV center.
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