Abstract: The present document relates to a heterodyne scanning probe microscopy (SPM) method for subsurface imaging, and includes: applying, using a transducer, an acoustic input signal to the sample, wherein the acoustic input signal has a frequency of at least 1 gigahertz; sensing an acoustic output signal using a probe, the probe including a cantilever and a probe tip, wherein the probe tip is in contact with the surface, wherein the acoustic output signal is representative of acoustic waves responsive to the acoustic input signal that are measurable at the surface; wherein the acoustic input signal is applied to the sample comprising a distinct pulse of acoustic energy followed by a relaxation period, wherein an acoustic power of the acoustic input signal during the pulse is at least twice as large as an acoustic power during the relaxation period. The present document further relates to a scanning probe microscopy method.

Abstract: Atomic force microscopy system comprising an atomic force microscopy device and a substrate carrier having a carrier surface carrying a substrate. The substrate has a substrate main surface and a substrate scanning surface opposite the substrate main surface. The atomic force microscopy device comprises a scan head including a probe. The probe comprises a cantilever and a probe tip arranged on the cantilever. The atomic force device further comprises an actuator cooperating with at least one of the scan head or the substrate carrier for moving the probe tip and the substrate carrier relative to each other in one or more directions parallel to the carrier surface for scanning of the substrate scanning surface with the probe tip. A signal application actuator applies, during said scanning, an acoustic input signal to the substrate, said acoustic input signal generating a first displacement field in a first displacement direction only.

Abstract: Atomic force microscopy system comprising an atomic force microscopy device and a substrate carrier having a carrier surface carrying a substrate. The substrate has a substrate main surface and a substrate scanning surface opposite the substrate main surface. The atomic force microscopy device comprises a scan head including a probe. The probe comprises a cantilever and a probe tip arranged on the cantilever. The atomic force device further comprises an actuator cooperating with at least one of the scan head or the substrate carrier for moving the probe tip and the substrate carrier relative to each other in one or more directions parallel to the carrier surface for scanning of the substrate scanning surface with the probe tip. A signal application actuator applies, during said scanning, an acoustic input signal to the substrate, said acoustic input signal generating a first displacement field in a first displacement direction only.

Abstract: The invention relates to an acoustic monitoring system comprising at least two isolated acoustic receivers (101a, 101b), such as hydrophones, for receiving acoustic signals from an acoustic source (16) and capable of spatial displacement, a detector for detecting signals from the said receivers and a processing system (110) for processing the detected signals for determining a spatial position of the said receivers and/or a direction to the acoustic source (16). The invention further relates to a method of acoustic monitoring.

Abstract: A portable threat detection apparatus and method is disclosed which may comprise a plurality of acoustic emission sensors arranged in a cluster, forming a polygon defining at least two axes of alignment between respective pairs of acoustic emission sensors; a computing device in cooperation with a non-transitory computer readable storage medium comprising computer readable instructions for performing: receiving a first signal produced by a first acoustic emission sensor within a respective pair of acoustic emission sensors, in response to the first acoustic emission sensor detecting an acoustic emission from a source, and receiving a second signal produced by a second acoustic emission sensor within the respective pair of acoustic emission sensors, in response to the second acoustic emission sensor detecting the acoustic emission; determining a cross-correlation factor between the first signal and the second signal; and, determining a bearing to the source based on the cross correlation factor.

Abstract: A portable threat detection apparatus and method is disclosed which may comprise a plurality of acoustic emission sensors arranged in a cluster, forming a polygon defining at least two axes of alignment between respective pairs of acoustic emission sensors; a computing device in cooperation with a non-transitory computer readable storage medium comprising computer readable instructions for performing: receiving a first signal produced by a first acoustic emission sensor within a respective pair of acoustic emission sensors, in response to the first acoustic emission sensor detecting an acoustic emission from a source, and receiving a second signal produced by a second acoustic emission sensor within the respective pair of acoustic emission sensors, in response to the second acoustic emission sensor detecting the acoustic emission; determining a cross-correlation factor between the first signal and the second signal; and, determining a bearing to the source based on the cross correlation factor.

Abstract: A method for focusing broadband acoustic signals with flat spectral content based on Time-Reversed Acoustics (TRA) principle is disclosed. The method of the invention differs from the conventional TRA focusing in that it includes an additional step of adjusting the spectral content of time-reversed signal, prior to applying it to the radiating transducer. This additional step, which includes attenuation of the spectral components with high amplitude and amplification of the spectral components with low amplitude, leads to flattening of the spectra of the radiated signal and widening of its frequency band. TRA focusing with this additional step of adjusting spectral content of the radiated signal allows generation of shorter pulses and provides better concentration of acoustic energy than standard TRA focusing.