An apparatus for carrying out spatially resolved photoacoustics includes a sample holder configured to receive a sample to be examined, an electroacoustic transducer in the region of the sample holder configured to detect acoustic waves excited by light beams on the sample, and a light beam device configured to emit a plurality of light beams that are spatially and temporally separated from one another onto the sample in order to generate acoustic waves at spatially separated positions on the sample.

A method for testing a lifetime of a surface state carrier of a semiconductor, including the following steps, 1) a narrow pulse light source is used to emit a light pulse, and coupled to an interior of a near-field optical probe, and the near-field optical probe produces a photon-generated carrier on a surface of a semiconductor material under test through excitation. 2) The excited photon-generated carrier is concentrated on the surface of the semiconductor material, and recombination is conducted continuously with a surface state as a recombination center. 3) A change in a lattice constant is produced due to an electronic volume effect, a stress wave is produced, and a signal of the stress wave is detected in a high-frequency broadband ultrasonic testing mode. 4) Fitting calculation is conducted on the signal of the stress wave to obtain the lifetime of the surface state carrier τ.sub.c.

A device and a method for simultaneously inspecting defects of a surface and a subsurface of an optical element are provided. Combined with laser-induced ultrasound and laser scattering inspection technologies, through generating acoustic sound waves on the surface and the subsurface of the optical element to be tested by lasers, a static light scattering effect of subsurface defects under modulation of the acoustic sound wave is observed and analyzed; through analyzing amplitude and phase changes of scattered light intensity and reflected light intensity, inspection for the defects of the surface and the subsurface of the optical element is realized. The present invention can be applied in quality inspection of precise optical elements, especially in finished product inspection of ultra-precise optical elements having strict requirements on the subsurface defects.

A system and a method for sensing an object using two-stage photo-acoustic excitation are provided herein. The method may include: scanning the object at a first resolution by alternately and repeatedly photo-acoustically exciting and sensing each of multiple first regions on the object to yield multiple first outputs; determining, based on the multiple first outputs, at least one first region of the multiple first regions that includes at least one zone and a specific depth of the at least one zone below a surface of the object; scanning the first region that includes the at least one zone at a second resolution by alternately and repeatedly photo-acoustically exciting and sensing each of multiple second regions in the at least one first region thereof to yield multiple second outputs; and determining, based on at least one of the multiple second outputs, specified parameters of the at least one zone.

A method for visualizing details in a sample including directing an excitation beam to an excitation location below a surface of the sample, to generate signals in the sample; directing an interrogation beam toward the excitation location of the sample; directing a signal enhancement beam to the sample, to raise a temperature of a portion of the sample by 5 Kelvin or less, compared to a temperature of the portion of the sample in absence of the signal enhancement beam; detecting a portion of the interrogation beam returning from the sample that is indicative of the generated signals.

A first signal is generated with a first light detector in response to an ultrasound signal encountering a first measurement beam. A second signal is generated with a second light detector in response to the ultrasound signal encountering a second measurement beam. The second measurement beam propagates through the sample and the first measurement beam propagates outside the sample.

A method and apparatus for detecting a photoacoustic light signal to prevent unauthorized voice commands for a microphone-controllable device are provided. The method includes receiving, by a processor, a signal, detecting, by the processor, that the signal is a photoacoustic signal generated by a thermal expansion and contraction of an object caused by at least one lightwave applied to the object, and activating, by the processor, a counter-measure to prevent the photoacoustic signal from reaching a microphone of a microphone-controllable device in response to detecting the photoacoustic signal.

An object information obtaining apparatus includes an irradiation unit configured to irradiate the object with measurement light, a probe configured to receive an acoustic wave propagating from the object, a driving unit configured to move the irradiation unit so that a relative position of the irradiation unit with respect to the object is changed, an image capturing unit configured to capture an image of the object and a control unit. The control unit is configured to control a display unit in such a manner that an irradiation position of the measurement light is displayed on the image captured by the image capturing unit.

A photoacoustic detecting device to be applied, via a contact face, against a medium to be analyzed, is disclosed. The device includes: a hollow cavity that opens onto a contact aperture, the contact aperture being produced in the contact face; a pulsed or amplitude-modulated light source configured to emit, when activated, an incident light beam, in an emission spectral band, through the cavity, to the contact aperture; and an acoustic transducer connected to the cavity and configured to detect a photoacoustic wave extending through the cavity. Under the effect of illuminating the medium by the incident light beam, the acoustic transducer detects an acoustic wave produced by heating the medium. The cavity includes a membrane extending through the cavity, facing the contact face. The membrane is bounded by a lower face and an upper face. The membrane includes through-apertures produced between the lower face and the upper face.

A photoacoustic gas sensor device is proposed for determining a value indicative of a presence or a concentration of a component in a gas. The photoacoustic gas sensor device comprises a substrate, and a measurement cell body arranged on a first side of the substrate. The substrate and the measurement cell body define a measurement cell enclosing a measurement volume. The measurement cell comprises an aperture for a gas to enter the measurement volume. The device further comprises an electromagnetic radiation source for emitting electromagnetic radiation, and a microphone for measuring a sound wave generated by the component in response to an absorption of electromagnetic radiation by the component. The electromagnetic radiation source and the microphone are arranged on the first side of the substrate and in the measurement volume. The microphone has a bottom port facing the substrate, and the measurement volume is communicatively coupled to the bottom port.