Embodiments of systems for classifying interference signals are disclosed. In an example, a system for classifying interference signals includes an interferometer including a light source and a detector, and at least one processor. The interferometer is configured to provide a plurality of interference signals each corresponding to a respective one of a plurality of positions on a surface of a semiconductor chip. A spectrum of the light source is greater than a spectrum of white light. The at least one processor is configured to classify the interference signals into a plurality of categories using a model. Each of the categories corresponds to a region having a same material on the surface of the semiconductor chip.

Optical coherence tomography (OCT) probe and system designs are disclosed that minimize the effects of mechanical movement and strain to the probe to the OCT analysis. It also concerns optical designs that are robust against noise from the OCT laser source. Also integrated OCT system-probes are included that yield compact and robust electro-opto-mechanical systems along with polarization sensitive OCT systems.

The embodiments herein relate to a method for deriving topography of an object surface. A linearly polarized light wave is directed towards the object surface and a reference surface. Images of reflected linearly polarized light wave for a plurality of wavelengths are obtained. The images are obtained for at least four polarizations for each of the plurality of wavelengths. The reflected linearly polarized light wave is a reflection of the linearly polarized light wave directed towards the object surface and the reference surface. The topography of the object surface based on the obtained images is obtained.

Optical pressure sensor assemblies that can be used with existing catheters and imaging systems. Pressure sensors may be compatible with atherectomy and occlusion-crossing catheters, where intravascular pressure measurements at various vessel locations are needed to determine treatment efficacy. The pressure sensors may employ an optical pressure measurement mechanism using optical interferometry, and may be integrated with existing imaging modalities such as OCT. The pressure sensor assemblies may include a movable membrane that deflects in response to intravascular pressure; an optical fiber that transmits light to the movable membrane and receives light reflected or scattered back from the movable membrane into the fiber; and a processor or controller configured to determine the distance traveled by the light received in the fiber from the movable membrane, where the distance traveled is proportional to the intravascular pressure exerted against the membrane.

A compensation optical unit (30) for a measurement system (10) for determining a shape of an optical surface (12) of a test object (14) by interferometry generates a measuring wave (44), directed at the test object, with a wavefront that is at least partly adapted to a target shape of the optical surface from an input wave (18). The unit includes first (32) and second (34) optical elements disposed in a beam path of the input wave. The second optical element is a diffractive optical element configured to split the input wave into the measuring wave and a reference wave (42) following an interaction with the first optical element. At least 20% of a refractive power of the entire compensation optical unit is allotted to the first optical element, and this allotted refractive power has the same sign as the refractive power of the entire compensation optical unit.

A method for calibrating a measuring device (10) for interferometrically determining a shape of an optical surface (12) of an object under test (14). The measuring device includes a module plane (32) for arranging a diffractive optical test module (30) which is configured to generate a test wave (34) that is directed at the optical surface and that has a wavefront at least approximately adapted to a target shape (60) of the optical surface. The method includes: arranging a diffractive optical calibration module (44) in the module plane for generating a calibration wave (80), acquiring a calibration interferogram (88) generated using the calibration wave in a detector plane (43) of the measuring device, and determining a position assignment distribution (46) of points (52) in the module plane to corresponding points (54) in the detector plane from the acquired calibration interferogram.

The disclosure provides a microphone chip, a microphone, and a terminal device. The microphone chip includes a substrate and a diaphragm that are disposed oppositely, a reflector located on a side that is of the diaphragm and that is close to the substrate, a grating group located between the substrate and the diaphragm, and an optical emitter and an optical detector that are located between the substrate and the grating group. The grating group includes a plurality of gratings, and distances between at least two gratings in the plurality of gratings and the reflector are different.

A portable communication device includes one or more optical detectors to generate an analog signal in response to a change in an intra-cavity or an emitted optical power of a light source due to light backscattered from a particle and an application-specific integrated circuit (ASIC). The particle is illuminated via a light source. The ASIC includes an analog-to-digital converter (ADC) circuit, a digital delay circuit, a particle detector module and a processor. The ADC converts the analog signal to a digital signal. The digital delay circuit can store the digital signal for a predetermined or dynamically variable time interval. The particle detector module can analyze the digital signal and can generate an enable signal upon detecting a particle signature in the digital signal. The processor is coupled to the digital delay circuit and can start processing the digital signal in response to the enable signal.

A testing device for measuring the homogeneity of an optical element in a beam path of the testing device and related method. The testing device includes an interferometer, which comprises a monochromatic light source, an adjustable objective, a reference surface associated with a surface of the optical element to be tested or an interferometry surface, and an analysis unit for the interference of the wave fronts of the light reflected by the reference surface and the associated surface of the optical element to be tested or of the interferometry surface. The testing device and method facilitate highly precise measurement of the homogeneity of an entire optical element—not merely individual surfaces. The method is suitable for the highly precise measurement of plastic lenses or other injection molded components for refractive laser eye surgery for example.

A machining head is provided for a laser machining system configured to machine a workpiece using a laser beam. The machining head includes a housing having an opening for emitting the laser beam from the machining head; at least one reflective reference at the housing; and a measuring device configured to direct an optical measurement beam towards the opening and the at least one reflective reference. The measuring device is further configured to determine a distance (d1) between the end portion and the workpiece on the basis of a first reflection (A) of the optical measurement beam from the at least one reflective reference and a second reflection (B) of the optical measurement beam from the workpiece.