New FM detection techniques for scanning probe microscopy

2019-08-07 21:49:11

The frequency FM techniques Japan

责任者: Kobayashi, Dai;Kawai, Shigeki;Kawakatsu, Hideki 单位: CREST, Japan Science and Technology Agency, Kawaguchi, Saitama-ken 332-0012, Japan 来源出处: Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers,2004,43(7 B):4566-4570 摘要: New FM demodulation techniques capable of detecting the fast frequency deviation of a cantilever of a noncontact atomic force microscope are proposed and their features were demonstrated by experiments. The techniques entail the frequency conversion of an input FM signal to a pair of zero-Hz-centered signals with a mutual phase difference of 90deg, differentiation or Hilbert transformation, multiplication and subtraction. Since the center frequency and scale factor are determined by different processes, a high sensitivity, a fast response and a precise center frequency are achievable at the same time. The developed circuitry is capable of detecting a minimum frequency shift of 0.1 Hz. The maximum response bandwidth is 100 kHz. 关键词: Atomic force microscopy;Frequency modulation;Signal processing;Resonance;Demodulation;Feedback;Gain control;Mathematical transformations;AFM;Nanocantilever;FM demodulation;Direct conversion;Hilbert transformer