Intermittent-Contact Heterodyne Force Microscopy

Figure 2

(a) Fundamental and (b) second-order flexural cantilever resonances measured with the cantilever tip out-of-contact with the sample surface (free cantilever modes), in the absence of ultrasonic vibration. (c) FFT of the AFM photodiode signal in tapping mode operation: excitation frequency 𝜔₀=55.521KHz, set-point amplitude 𝑉 = 15% 𝑉₀.

(a)

(b)

(c)