The present document relates to a heterodyne scanning probe microscopy (SPM) method for subsurface imaging, and includes: applying an acoustic input signal to a sample and sensing an acoustic output signal using a probe. The acoustic input signal comprises a plurality of signal components at unique frequencies, including a carrier frequency and at least two excitation frequencies. The carrier frequency and the excitation frequencies form a group of frequencies, which are distributed with an equal difference frequency between each two subsequent frequencies of the group. The difference frequency is below a sensitivity threshold frequency of the cantilever for enabling sensing of the acoustic output signal. The document also describes an SPM system.

Mid-infrared photothermal heterodyne imaging (MIR-PHI) techniques described herein overcome the diffraction limit of traditional MIR imaging and uses visible photodiodes as detectors. MIR-PHI experiments are shown that achieve high sensitivity, sub-diffraction limit spatial resolution, and high acquisition speed. Sensitive, affordable, and widely applicable, photothermal imaging techniques described herein can serve as a useful imaging tool for biological systems and other submicron-scale applications.

Mid-infrared photothermal heterodyne imaging (MIR-PHI) techniques described herein overcome the diffraction limit of traditional MIR imaging and uses visible photodiodes as detectors. MIR-PHI experiments are shown that achieve high sensitivity, sub-diffraction limit spatial resolution, and high acquisition speed. Sensitive, affordable, and widely applicable, photothermal imaging techniques described herein can serve as a useful imaging tool for biological systems and other submicron-scale applications.

Apparatus and methods for measuring surface topography are described. The analysis apparatus and methods detect light reflected from the reflective backside of a cantilever assembly including a tip, calculate a background level (BGL) value obtained from an optical scan of a reference sample using a power spectral density (PSD) value obtained from a topographical scan of a reference sample to generate a correlational coefficient between the BGL and the PSD values. The correlational coefficient between the BGL and PSD values is used to measure the BGL value of additional EUV mask blanks by a topographical scan of the EUV mask blanks using the same tip mounted to the cantilever.

A method comprises using an atomic-force microscope, acquiring a set of images associated with surfaces, and, using a machine-learning algorithm applied to the images, classifying the surfaces. As a particular example, the classification can be done in a way that relies on surface parameters derived from the images rather than using the images directly.

A method comprises using an atomic-force microscope, acquiring a set of images associated with surfaces, and, using a machine-learning algorithm applied to the images, classifying the surfaces. As a particular example, the classification can be done in a way that relies on surface parameters derived from the images rather than using the images directly.

A method for detecting a thickness of bonded rubber of a carbon black in a natural rubber based for reinforcement performance is provided. An ultra-thin frozen microtome to prepare a sample, a tapping mode of the atomic force microscope is used, and when characterizes the carbon black and rubber composite material, the difference of imaging characteristics between morphological and phase diagrams is used, the characteristics of bonded rubber of carbon black reinforced composite material can be observed to obtain the thickness of bonded rubber, and then influence of bonded rubber on rubber performance and the reinforcement performance of the carbon black in the rubber are analyzed. The method has advantages of simple operation, no need for excessive sample processing, high detection efficiency, clear detection images and high detection accuracy, thereby having better applicability and providing a new method and idea for studying reinforcements of fillers.

An atomic force microscope includes a cantilever operating in amplitude modulation mode. A controller determines the amplitude of the cantilever oscillation by processing a signal representative of the cantilever motion by square-rooting a signal having a value substantially equal to a sum of a square of the received signal and a squared and phase-shifted version of the received signal. The aforementioned processing, in some implementations is implemented using analog circuit components.

An atomic force microscope includes a cantilever operating in amplitude modulation mode. A controller determines the amplitude of the cantilever oscillation by processing a signal representative of the cantilever motion by square-rooting a signal having a value substantially equal to a sum of a square of the received signal and a squared and phase-shifted version of the received signal. The aforementioned processing, in some implementations is implemented using analog circuit components.

A method of compensating for an artifact in data collected using a standard atomic force microscope (AFM) operating in an oscillating mode. The artifact is caused by deflection of the probe not related to actual probe-sample interaction and the method includes compensating for thermal induced bending of the probe of the AFM by measuring a DC component of the measured deflection. The DC component of deflection is identified by calibrating the optical deflection detection apparatus and monitoring movement of the mean deflection, thereby allowing the preferred embodiments to minimize the adverse effect due to the artifact. Notably, plotting the DC deflection profile yields a corresponding temperature profile of the sample.