Multipoint photo-acoustic measuring device
AssigneeNeta
InventorsAllaoua Abbas, Yohann Hereau, Julien Michelon, Xavier Tridon
Life of this patent
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Abstract
A method comprises non-destructive contact-free physical characterization of a sample by repeated excitations of the surface of a sample with a sequence of pulses comprising at least one pump pulse by a first “pump” laser followed by a succession of L temporarily offset pulses by a second “probe” laser, and the analysis of the beam emitted by the surface of the sample by an activated photodetector, for the acquisition of signals delivered by the photodetectors during constant time windows.
Claims18
A non-destructive and contact-free method for physical characterization of a sample, comprising:
- repeatedly exciting a surface of the sample with pump and probe beams comprising a sequence of pulses, the sequence of pulses comprising at least one pump pulse produced by a pump laser followed by a plurality of L probe pulses produced by a probe laser, the plurality of L probe pulses having different temporal offsets with respect to the at least one pump pulse;
- receiving, with a photodetector, the plurality of L probe pulses in the sequence of pulses after interacting with the surface of the sample;
- wherein:
- the photodetector comprises an N-dimensional array of a plurality of M photosensitive elements, wherein N is one or two;
- and
- for each photosensitive element of the plurality of M photosensitive elements, a signal value is determined based on a signal produced by the photosensitive element in response to one probe pulse after the one probe pulse interacts with the surface of the sample;
- recording, for each sequence of pulses, an array of MxL signal values delivered by the plurality of M photosensitive elements;
- and
- applying a transformation to the array of M×L signal values to determine a map of a zone of the sample in a form of an array of values of a physical characteristic observed for at least one point of the zone.
A system for non-destructive and contact-free physical characterization of a sample, comprising:
- two pulsed laser sources configured to emit respectively a pump beam comprising at least one pump pulse and a probe beam comprising a plurality of L probe pulses, wherein the plurality of L probe pulses have different temporal offsets with respect to the at least one pump pulse;
- a detector configured to receive probe pulses after interacting with a surface of the sample, the detector comprising an N-dimensional array of a plurality of M photosensitive elements, wherein N is one or two, and wherein, for each photosensitive element of the plurality of M photosensitive elements, signal values are determined based on signals produced by the photosensitive element in response to the plurality of L probe pulses after interacting with the surface of the sample;
- and
- a computer configured to control a recording of an array of MxL signal values delivered by the plurality of M photosensitive elements and to apply a transformation to the array of MxL signal values to determine a map of a zone of the sample in a form of an array of values of a physical characteristic observed for at least one point of the zone.
Dependencies are inferred from the claim text.