A passive-phase-detection photothermal spectroscopy (PTS) system and methods are provided for gas measurements. The PTS system includes a pump laser source, a probe laser source, the pump and probe laser beams simultaneously propagating through an optical waveguide having a target gas specimen. Moreover, the PTS system can be based on a heterodyne detection scheme and includes a combiner configured to align light input from a local oscillator with the probe laser beam output from the optical waveguide to output to a photodetector that is configured to generate beat notes. A demodulation module is configured to detect and measure a photothermal signal based on the beat notes received from the photodetector for gas measurements. The PTS system can also be based on a core-cladding-mode interference detection scheme and generates the core mode and cladding mode simultaneously for the probe laser in the waveguide.

A passive-phase-detection photothermal spectroscopy (PTS) system and methods are provided for gas measurements. The PTS system includes a pump laser source, a probe laser source, the pump and probe laser beams simultaneously propagating through an optical waveguide having a target gas specimen. Moreover, the PTS system can be based on a heterodyne detection scheme and includes a combiner configured to align light input from a local oscillator with the probe laser beam output from the optical waveguide to output to a photodetector that is configured to generate beat notes. A demodulation module is configured to detect and measure a photothermal signal based on the beat notes received from the photodetector for gas measurements. The PTS system can also be based on a core-cladding-mode interference detection scheme and generates the core mode and cladding mode simultaneously for the probe laser in the waveguide.

The device for detecting and/or determining the concentration of an analyte present in a tissue includes a sensor which is an optical fibre interferometer, and one interferometer arm being coated with an immobilised binding agent enabling selective binding of the analyte. The interferometer arm is mounted inside a guide enabling puncturing the tissue and performing an in situ measurement without the necessity to collect or prepare a sample. The guide is provided with a closed guide face, longitudinal perforations on sidewalls enabling the analyte to reach the binding agent, and an opening in the input end of the guide for introducing the interferometer with the arm into the guide. At the input end, the opening is sealed, enabling the isolation of the interior of the guide from the surroundings. The interferometer is mounted in a position in which the interferometer does not touch the inside walls of the guide.

The device for detecting and/or determining the concentration of an analyte present in a tissue includes a sensor which is an optical fibre interferometer, and one interferometer arm being coated with an immobilised binding agent enabling selective binding of the analyte. The interferometer arm is mounted inside a guide enabling puncturing the tissue and performing an in situ measurement without the necessity to collect or prepare a sample. The guide is provided with a closed guide face, longitudinal perforations on sidewalls enabling the analyte to reach the binding agent, and an opening in the input end of the guide for introducing the interferometer with the arm into the guide. At the input end, the opening is sealed, enabling the isolation of the interior of the guide from the surroundings. The interferometer is mounted in a position in which the interferometer does not touch the inside walls of the guide.

According to one embodiment, an optical test apparatus includes a first aperture, a second aperture, an image sensor, and a first lens. The first aperture includes a first aperture plane provided with a first wavelength selecting region. The second aperture includes a second aperture plane provided with a second wavelength selecting region different from the first wavelength selecting region. The image sensor is configured to image a light beam passing through the first aperture plane and the second aperture plane and reaching an imaging plane. The first lens is configured to make a light beam passing through the first aperture plane and the second aperture plane be incident on the imaging plane.

A method is provided for detecting primary gas flows (18) in flow chambers (10). The primary gas (18) flowing in a flow chamber (10) is locally seeded with a seed substance and the movement of the seed substance, representative of the flow of the primary gas (18), is detected by imaging by an image detector (28) and an imaging optics (30) arranged in front of said image detector (28). A gas mixture (34) that moves along with the primary gas (18) without relative motion and that has a refractive index distinguishable from that of the primary gas (18) is used as the seed substance, and imaging detection is carried out by a background schlieren measurement method.

In one aspect, there is provided a system including at least one processor; and at least one memory including program code which when executed by the at least one processor causes operations including capturing an image of at least a portion of a surface of an object; generating, from the captured image, pixel intensity data; in response to generating the pixel intensity data, determining, based on a height error model, height error data, wherein the height error data indicates an uncertainty of at least one height measurement of the object; and determining, based on the height error data, whether the object satisfies a threshold criteria for acceptance of the object. Related system, methods, and articles of manufacture are also disclosed.

In one aspect, there is provided a system including at least one processor; and at least one memory including program code which when executed by the at least one processor causes operations including capturing an image of at least a portion of a surface of an object; generating, from the captured image, pixel intensity data; in response to generating the pixel intensity data, determining, based on a height error model, height error data, wherein the height error data indicates an uncertainty of at least one height measurement of the object; and determining, based on the height error data, whether the object satisfies a threshold criteria for acceptance of the object. Related system, methods, and articles of manufacture are also disclosed.

A method and apparatus for measuring a 3-D refractive index tensor are presented. The method for measuring a 3-D refractive index tensor according to an embodiment comprises the steps of: controlling incident light of a plane wave with respect to at least one angle and polarization; and measuring, in a polarization-dependent manner, the 2-D diffracted light of a specimen with respect to the incident light incident at the at least one angle and polarization, wherein the birefringence value and the 3-D structure of an alignment direction of molecules in the specimen having birefringence may be measured.

A spatial modulator is provided on a plane conjugate to a sample plane on which a sample is to be placed. The spatial modulator spatially modulates illumination light irradiated to the sample 2 or object light that has passed through or that has been reflected by the sample. A dark-field optical system removes the non-scattered light component of the first object light affected by the spatial light modulator so as to generate second object light. An image sensor records a hologram based on the second object light. A calculation processing apparatus combines complex amplitude information based on the modulation pattern supplied to the spatial light modulator and complex amplitude information based on the hologram with respect to the second object light so as to acquire a phase distribution originating from the sample.