A non-destructive opto-acoustic metrology device detects the presence and location of non-uniformities in a film stack that includes a large number, e.g., 50 or more, transparent layers. A transducer layer at the bottom of the film stack produces an acoustic wave in response to an excitation beam. A probe beam is reflected from the layer interfaces of the film stack and the acoustic wave to produce an interference signal that encodes data in a time domain from destructive and constructive interference as the acoustic wave propagates upward in the film stack. The data may be analyzed across the time domain to determine the presence and location of one or more non-uniformities in the film stack. An acoustic metrology target may be produced with a transducer layer configured to generate an acoustic wave with a desired acoustic profile based on characteristics of the film stack.

Aspects relate to on-line compensation of instrumental drifts in miniaturized spectrometers due to variations in environmental conditions and due to other sources of instrumental drift. The spectrometer may include a light modulator, a detector, and a processor. The spectrometer may further include a sensor configured to obtain a value of a condition contributing to instrumental drifts in the spectrometer. The processor may be configured to extract a set of correction parameters from a correction matrix associating a plurality of sets of correction parameters with sensor values based on the value and to apply the set of correction parameters to an output of the detector to produce a corrected spectrum of a sample under test. The correction matrix may be generated for the spectrometer or may be based on a global correction matrix fitted to the spectrometer.

Embodiments herein provide a method and system for a non-invasive mechanism providing simultaneous determination of viscosity-temperature variation of a lubricant for predicting machine health using a Photo Acoustic (PA) sensing mechanism, Laser-enabled swept frequency acoustic interferometry (LE-SFAI), wherein the lubricant produces acoustic wave only if it absorbs the laser irradiation, thus overcomes the limitation of ultrasound based SFAI through optical absorption based contrast and proper selection of laser excitation wavelength. A PA signal received from the lubricant is processed by a Vector Network Analyzer (VNA), then converted to time domain to obtain normalized first peak that corresponds to the PA signal generated by the lubricant. A squared rise time of the first peak is indicative of viscosity of the liquid and shift in the first peak is indicative of variation of the viscosity as temperature of the lubricant varies.

A method and system of nanoscale photoacoustic tomography (nPAT) for non-invasive three-dimensional mapping and characterization of fine cellular structures (such as but not limited to organelles, vesicles, and macromolecules) of biological samples is disclosed.

Described herein is a system for determining structural characteristics of an object, the system including a first laser, a second laser, one or more processors, and a computer readable medium storing instructions that, when executed by the one or more processors, cause the system to perform functions. The functions include illuminating, by the first laser, a surface region of an object with an incident light pulse, thereby causing the object to exhibit vibrations; illuminating, by the second laser, the surface region with an incident light beam, thereby generating responsive light that is indicative of the vibrations; detecting the responsive light and determining a difference between a characteristic of the responsive light and a reference characteristic that corresponds to the surface region; determining a position of the surface region within a three-dimensional space; and displaying the surface region such that the difference is indicated at the position of the surface region.

Acoustically mediated pulsed radiation sources, phased arrays incorporating the radiation sources, and methods of using the radiation sources and phased arrays to generate electromagnetic radiation via magnetic dipole emission are provided. The radiation sources are based on a superlattice heterostructure that supports in-phase magnetic dipole emission from a series of magnetic insulator layers disposed along the length of the heterostructure.

This disclosure presents a process to determine characteristics of a subterranean formation proximate a borehole. Borehole material can be typically pumped from the borehole, though borehole material can be used within the borehole as well. Extracted material of interest can be collected from the borehole material and prepared for analyzation. Typically, the preparation can utilize various processes, for example, separation, filtering, moisture removal, pressure control, cleaning, and other preparation processes. The prepared extracted material can be placed in a photoacoustic device where measurements can be taken, such as a photoacoustic imager or a photoacoustic spectroscopy device. A photoacoustic analyzer can generate results utilizing the measurements, where the results of the extracted material can include one or more of fracture parameters, fracture plane parameters, permeability parameters, porosity parameters, and composition parameters. The results can be communicated to other systems and processes to be used as inputs.

Disclosed herein is a transparent ultrasonic sensor-based ultrasonic optical composite imaging system including at least one light source and a transparent ultrasonic sensor coaxially aligned with light emitted from the light source and allowing the light emitted from the light source to be transmitted therethrough, wherein the transparent ultrasonic sensor is disposed between the light source and a subject.

Techniques for detecting cannabinoid, opioid, and virus aerosols in an exhaled breath are provided. An example method for analyzing exhaled breath includes receiving an aerosol breath sample, concentrating the aerosol breath sample onto an infrared-transparent coupon with an electrostatic precipitator, disposing the infrared-transparent coupon in an optical path of a spectroscopy system, detecting one or more infrared spectral features of the concentrated aerosol breath sample with the spectroscopy system, and analyzing the aerosol breath sample based on the one or more infrared spectral features.

The present invention discloses a method for detecting a microstructure of a functionally graded material based on digital acousto-optic holography, including the following steps: excite a sample with an ultrasonic wave; record a light wave; form a single tomographic acousto-optic hologram; perform numerical reconstruction of phase information, and perform global detection. The present invention uses an acoustic-optic modulation device to modulate a laser light source of a laser of a laser device to form two light waves of different frequencies. The two light waves each constitute a Mach-Zehnder interference system to record reflection wave information and transmission wave information of an ultrasound, and are finally combined and recorded in the same hologram to form the single tomographic acousto-optic hologram.