An optical sensor system including a semiconductor substrate; a self-mixing interferometry (SMI) sensor formed on the semiconductor substrate and including a semiconductor laser having a resonant cavity; and an array of photodetectors formed on the semiconductor substrate. The SMI sensor is configured to generate an SMI signal responsive to a retro-reflection of electromagnetic radiation emitted by the semiconductor laser and received into the resonant cavity. The array of photodetectors is configured to generate a set of angular-resolved scatter signals responsive to a scatter of the electromagnetic radiation emitted by the semiconductor laser.

A wearable electronic device including a housing that is worn by a user and a SMI sensor contained within the housing. The SMI sensor may include an emitter that outputs coherent light toward the skin of a user when the housing is worn by the user. The SMI sensor may also include a detector that detects a portion of the coherent light reflected towards the sensor and generates electrical signals that indicate displacements of the skin based on the portion of coherent light received at the detector. The housing may include a transmitter that is operatively coupled with the SMI sensor and is configured to transmit physiological data to a receiving device based on electrical signals output from the SMI sensor.

An eyebox region is illuminated with first coherent light and second coherent light having a different wavelength than the first coherent light. A first self-mixed interferometer (SMI) signal is generated in response to first feedback light received back from the eyebox region. A second SMI signal is generated in response to second feedback light received back from the eyebox region. Eye data is generated in response to at least the first SMI signal and the second SMI signal.

A laser sensor module includes a first laser source configured to emit first modulated light, the first modulated light being modulated laser light. The laser sensor module further includes circuitry configured to drive the first laser source with a first modulated driving current to cause the first laser source to emit the modulated laser light, a detector configured to detect the modulated laser light, which induces a photocurrent with variations resulting from modulation of the modulated laser light, and a second laser source configured to emit second modulated light. The circuitry is further configured to drive the second laser source with a second modulated driving current to cause the second laser source to emit the second modulated light. The detector is configured to detect the second modulated light. The circuitry is configured to adapt the amplitude of the second modulated driving current to induce a contribution to the photocurrent.

An electronic device is described. The electronic device includes a housing, a set of one or more SMI sensors attached to the housing, and a processor. The set of one or more SMI sensors includes a set of one or more electromagnetic radiation emitters having a set of one or more resonant cavities and configured to emit a set of one or more beams of electromagnetic radiation. The set of one or more SMI sensors also includes a set of one or more detectors configured to generate indications of self-mixing within the set of one or more resonant cavities. The processor is configured to characterize, using the indications of self-mixing, an optical field speckle of a target. The processor is also configured to characterize, using the characterization of the optical field speckle, a surface quality of the target.

A thickness evaluation method of the cell sheet according to the invention includes tomographically imaging a cell sheet by optical coherence tomography and obtaining a thickness distribution of the cell sheet based on a result of the tomography imaging. A tomographic image corresponding to one cross section of the cell sheet is obtained by tomography imaging while scanning the light in a main scanning direction. The tomography imaging is performed in every time while moving an incident position of the light at a predetermined feed pitch in a sub-scanning direction, thereby a plurality of the tomographic images corresponding to a plurality of cross-sections are obtained. One-dimensional thickness distributions of the cell sheet in the corresponding cross-sections are obtained based on each of the plurality of tomographic images, and a two-dimensional thickness distribution of the cell sheet is obtained by interpolating the one-dimensional thickness distributions.

Methods and systems concerning non-reciprocal sensing paths for a self-mixing interferometry operation are disclosed herein. Optical components may be used to direct light transmit from a light source along an illumination path. The optical components may additionally return light to the light source after being reflected from a target and may direct the returned light along a collection path. The illumination path and the collection path may be at least partially non-reciprocal so that the transmitted light and the returned light follow along partially different paths. Once the received light is received within a cavity of the light source, a self-mixing interferometry operation may be performed and may be used to detect a property of the target in relation to the light source.

Disclosed herein are electronic devices having touch input surfaces. A user's touch input or press on the touch input surface is detected using a set of lasers, such as vertical-cavity surface-emitting lasers (VCSELs) that emit beams of light toward the touch input surface. The user's touch causes changes in the self-mixing interference within the VCSEL of the emitted light with reflected light, such as from the touch input surface. Deflection and movement (e.g., drag motion) of the user's touch is determined from detected changes in the VCSELs' operation due to the self-mixing interference.

The invention describes a laser sensor module (100) for detecting ultra-fine particles (10) with a particle size of 300 nm or less, more preferably 200 nm or less, most preferably 100 nm or less, the laser sensor module (100) comprising: —at least one laser (110) being adapted to emit laser light to at least one focus region in reaction to signals provided by at least one electrical driver (130), —at least one detector (120) being adapted to determine a self-mixing interference signal of an optical wave within a laser cavity of the at least one laser (110), wherein the self-mixing interference signal is caused by reflected laser light reentering the laser cavity, the reflected laser light being reflected by a particle receiving at least a part of the laser light, —the laser sensor module (100) being arranged to perform at least one self-mixing interference measurement, —the laser sensor module (100) being adapted to determine a first particle size distribution function with a first sensitivity by means of at least one measurement result determined based on the at least one self-mixing interference measurement, the laser sensor module being further adapted to determine a second particle size distribution function with the second sensitivity, the second sensitivity being different from the first sensitivity, —the at least one evaluator (140) being adapted to determine a particle measure of the particle size of 300 nm or less by subtracting the second particle size distribution function multiplied with a calibration factor q from the first particle size distribution function. The invention further describes a corresponding method and computer program product. The invention enables a simple and low-cost particle detection module or particle detector based on laser self-mixing interference which can detect particles with a size of 100 nm or even less.

A method for ascertaining a viewing direction of an eye. A laser beam emitted by a laser source is passed over at least two scanning points on the eye, using a reflection element and a deflecting element. A self-mixing effect of the scanning laser beam reflected by the eye into the laser source is used, in order to determine, for the at least two scanning points, the optical path length from the laser source to the at least two scanning points on the surface of the eye and/or a reflectivity of the eye at the at least two scanning points.