Fig. 2: Experimental detection of acoustic vibrations. | Nature Communications

Fig. 2: Experimental detection of acoustic vibrations.

From: Ultrasensitive detection of local acoustic vibrations at room temperature by plasmon-enhanced single-molecule fluorescence

Fig. 2: Experimental detection of acoustic vibrations.

a Schematic of the arrangement of the experimental system. Inset shows the fluorescence image of a single crystal violet (CV) molecule; scale bar: 5 μm. b Fast Fourier transform (FFT) of the fluorescence intensity traces (with a bin size of 5 μs for a 200-s acquisition time) when driven with shifting voltages of 0.02−0.5 V at the resonant frequency. The significant sharp peak at 32.710 kHz indicates perfect modulation of the optical signal by the tuning fork. The limit voltage for a detectable signal is 0.05 V. c The FFT amplitude as a function of the driving voltage. The FFT peak is linearly proportional to the driving voltage. The fluorescence intensity was kept constant (∼26,000 counts s−1) for different driving voltages. The size of a CV molecule is about 2 nm. The red solid line is the linear fitting of the experimental data (solid scattered points).

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