Analog frequency modulation detector for dynamic force microscopy

Analog frequency modulation detector for dynamic force microscopy

A new analog frequency modulation ~FM! detector ~demodulator! for dynamic force microscopy ~DFM! is presented. The detector is designed for DFM by utilizing the FM detection method where the resonance frequency shift of the force sensor is kept constant to regulate the distance between a tip and a sample surface. The FM detector employs a phase-locked loop ~PLL! circuit using a voltage-controll...

Wideband digital frequency detector with subtraction-based phase comparator for frequency modulation atomic force microscopy.

We have developed a wideband digital frequency detector for high-speed frequency modulation atomic force microscopy (FM-AFM). We used a subtraction-based phase comparator (PC) in a phase-locked loop circuit instead of a commonly used multiplication-based PC, which has enhanced the detection bandwidth to 100 kHz. The quantitative analysis of the noise performance revealed that the internal noise...

Self-oscillating mode for frequency modulation noncontact atomic force microscopy

Spatial horizons in amplitude and frequency modulation atomic force microscopy.

In dynamic atomic force microscopy (AFM) the cantilever is vibrated and its dynamics are monitored to probe the sample with nanoscale and atomic resolution. Amplitude and frequency modulation atomic force microscopy (AM-AFM and FM-AFM) have established themselves as the most powerful methods in the field. Nevertheless, it is still debatable whether one or the other technique is preferred in a g...

Physical interpretation of frequency-modulation atomic force microscopy

Frequency modulation atomic force microscopy is a method for imaging the surface of metals, semiconductors and insulators in ultrahigh vacuum with true atomic resolution. The imaging signal in this technique is the frequency shift D f of an oscillating cantilever with eigenfrequency f 0 , spring constant k and amplitude A, which is subject to tip-sample forces Fts . Here, we present analytical ...