Abstract: Provided is an atomic force microscope capable of increasing the phase detection speed of a cantilever vibration. The cantilever (5) is excited and the cantilever (5) and a sample are relatively scanned. Displacement of the cantilever (5) is detected by a sensor. An oscillator (27) generates an excitation signal of the cantilever (5) and generates a reference wave signal having a frequency based on the excitation signal and a fixed phase. According to vibration of the cantilever (5), a trigger pulse generation circuit (41) generates a trigger pulse signal having a pulse position changing in accordance with the vibration of the cantilever (5). According to the reference wave signal and the trigger pulse signal, a phase signal generation circuit (43) generates a signal corresponding to the level of the reference wave signal at the pulse position as a phase signal of vibration of the cantilever (5). As the reference wave signal, a saw tooth wave is used.

Abstract: There is provided an atomic force microscope (AFM) with increase the speed and sensitivity of detection of the resonant frequency shift in a cantilever. An AFM (1) extracts a reference signal and a phase shift signal from a detection signal from a displacement sensor of the cantilever. The reference signal is restrained from a phase change in accordance with the resonant frequency shift. The phase shift signal has a phase shifted in accordance with the resonant frequency shift. The AFM (1) determines the phase difference of the phase shift signal from the reference signal, as the resonant frequency shift. The AFM (1) may detect the phase difference between a plus-minus inversion point on the reference signal and a corresponding plus-minus inversion point on the phase shift signal. The AFM (1) may adjust phase before phase detection. The phase adjustment may move the detection point for the resonant frequency shift defined on the oscillation waveforms to the plus-minus inversion point.

Abstract: A driving laser unit (11) irradiates a laser beam on a cantilever (5) to cause thermal expansion deformation. A driving-laser control unit (13) performs feedback control for the cantilever (5) by controlling intensity of the laser beam on the basis of displacement of the cantilever (5) detected by a sensor (9). A thermal-response compensating circuit (35) has a constitution equivalent to an inverse transfer function of a heat transfer function of the cantilever (5) and compensates for a delay in a thermal response of the cantilever (5) to the light irradiation. Moreover, the cantilever (5) may be excited by controlling the intensity of the laser beam. By controlling light intensity, a Q value of a lever resonance system is also controlled. It is possible to increase scanning speed of an atomic force microscope.

Abstract: A scanning probe microscope is provided, which can be stably used for a long time even if excitation efficiency varies during scan. A cantilever (5) is excited, and the cantilever (5) and a sample are subjected to relative scanning. A second-harmonic component detection circuit (31) detects second-harmonic component amplitude of oscillation of the cantilever (5) as integral-multiple component amplitude. The second-harmonic component amplitude is amplitude of a second-harmonic component having a frequency twice as high as excitation frequency. An excitation intensity adjustment circuit (33) controls excitation intensity based on the detected second-harmonic component amplitude such that the second-harmonic component amplitude is kept constant.

Abstract: There is provided an atomic force microscope (AFM) with increase the speed and sensitivity of detection of the resonant frequency shift in a cantilever. An AFM (1) extracts a reference signal and a phase shift signal from a detection signal from a displacement sensor of the cantilever. The reference signal is restrained from a phase change in accordance with the resonant frequency shift. The phase shift signal has a phase shifted in accordance with the resonant frequency shift. The AFM (1) determines the phase difference of the phase shift signal from the reference signal, as the resonant frequency shift. The AFM (1) may detect the phase difference between a plus-minus inversion point on the reference signal and a corresponding plus-minus inversion point on the phase shift signal. The AFM (1) may adjust phase before phase detection. The phase adjustment may move the detection point for the resonant frequency shift defined on the oscillation waveforms to the plus-minus inversion point.

Abstract: A driving laser unit (11) irradiates a laser beam on a cantilever (5) to cause thermal expansion deformation. A driving-laser control unit (13) performs feedback control for the cantilever (5) by controlling intensity of the laser beam on the basis of displacement of the cantilever (5) detected by a sensor (9). A thermal-response compensating circuit (35) has a constitution equivalent to an inverse transfer function of a heat transfer function of the cantilever (5) and compensates for a delay in a thermal response of the cantilever (5) to the light irradiation. Moreover, the cantilever (5) may be excited by controlling the intensity of the laser beam. By controlling light intensity, a Q value of a lever resonance system is also controlled. It is possible to increase scanning speed of an atomic force microscope.

Abstract: A scanning probe microscope is provided, which can be stably used for a long time even if excitation efficiency varies during scan. A cantilever (5) is excited, and the cantilever (5) and a sample are subjected to relative scanning. A second-harmonic component detection circuit (31) detects second-harmonic component amplitude of oscillation of the cantilever (5) as integral-multiple component amplitude. The second-harmonic component amplitude is amplitude of a second-harmonic component having a frequency twice as high as excitation frequency. An excitation intensity adjustment circuit (33) controls excitation intensity based on the detected second-harmonic component amplitude such that the second-harmonic component amplitude is kept constant.

Abstract: Provided is an atomic force microscope capable of increasing the phase detection speed of a cantilever vibration. The cantilever (5) is excited and the cantilever (5) and a sample are relatively scanned. Displacement of the cantilever (5) is detected by a sensor. An oscillator (27) generates an excitation signal of the cantilever (5) and generates a reference wave signal having a frequency based on the excitation signal and a fixed phase. According to vibration of the cantilever (5), a trigger pulse generation circuit (41) generates a trigger pulse signal having a pulse position changing in accordance with the vibration of the cantilever (5). According to the reference wave signal and the trigger pulse signal, a phase signal generation circuit (43) generates a signal corresponding to the level of the reference wave signal at the pulse position as a phase signal of vibration of the cantilever (5). As the reference wave signal, a saw tooth wave is used.