TRUMPF PHOTONIC COMPONENTS GMBH

A laser sensor module includes a laser diode configured emit a laser beam, an electrical driver configured to supply the laser diode with a driving current to stimulate emission of the laser beam, a detector, and an optical arrangement configured to focus the laser beam to a focus region. The laser diode is arranged to emit the laser beam through the optical arrangement to the focus region. The optical arrangement comprises an emission window. The detector is arranged to determine an interference signal. The laser sensor module comprises a soiling detection unit configured to vary a wavelength of the laser beam with a variation amplitude over a predetermined time period to provide a soiling detection signal indicative of a soiling of the emission window based on an interference signal during the wavelength variation of the laser beam.

A laser arrangement includes a laser array, and an optical arrangement. The laser array includes lasers in a first pattern emitting a same laser emission profile around a first optical axis with a divergence angle θ/2. The optical arrangement has a diffusor with an array of optical elements in a second pattern, with a second optical axis, and with an illumination pattern along a first illumination axis in a field-of-view if laser light is received within a defined range smaller than or equal to a range of angles between −/+θ with respect to the second optical axis. A row of lasers parallel to the first illumination axis has a pitch p. A row of m optical elements is parallel to the first axis. Each optical element has a diameter L, and contacts its neighbor. The n lasers and the m optical elements satisfy n*p=m*L with a deviation smaller than +/−5%.

A Vertical Cavity Surface Emitting Laser (VCSEL) includes a layer stack of semiconductor layers having a first layer sub-stack forming a mesa, and a second layer sub-stack adjacent to the mesa in a stacking direction. Layers of the second layer sub-stack extend beyond layers of the first sub-stack in a direction perpendicular to the stacking direction. The semiconductor layers of the layer stack form an optical resonator having a first mirror, a second mirror, an active region between the first and second mirrors for laser light generation, and an oxide aperture layer forming a current aperture. The oxide aperture layer is made from Al 1-x Ga x As with 0≤x≤0.05. The oxide aperture layer is a last layer of the mesa and immediately adjacent to a first layer of the second layer sub-stack. A first layer of the second layer sub-stack is a contact layer.

A vertical cavity surface emitting laser (VCSEL) emits laser light. The VCSEL has an optical resonator and a photodiode. The optical resonator has: a first mirror, an active region configured to generate laser light, and a second mirror. The active region is arranged between the first mirror and the second mirror. The photodiode is integrated in the optical resonator. The photodiode has: an absorption region having a plurality of absorbing layers configured to absorb the generated laser light. The absorbing layers are arranged spaced apart from one another by a distance d which satisfies the condition: d=(2k−1)λ/(4 m). Where λ is the wavelength of the laser light in the absorption region, and k and m are natural numbers≥1.

A method for operating smart glasses includes an input unit and/or output unit and a gaze detection arrangement, wherein the gaze detection arrangement detects any eye movement of an eye including the steps of irradiating at least one wavelength-modulated laser beam to the eye, detecting an optical path length of the emitted laser beam based on laser feedback interferometry of the emitted laser radiation with backscattered radiation from the eye, detecting a Doppler shift of the emitted and backscattered radiation based on the laser feedback interferometry, and detecting an eye velocity based on the Doppler shift, and wherein the input unit and/or output unit is operated based on the optical path length and/or the eye velocity.

A method for detecting a gaze direction of an eye includes the steps of irradiating at least one wavelength-modulated laser beam onto an eye, detecting an optical path length of the emitted laser beam based on laser feedback interferometry of the emitted laser radiation with a backscattered radiation from the eye, detecting a Doppler shift of the emitted radiation and the backscattered radiation based on the laser feedback interferometry, detecting an eye velocity based on the Doppler shift, and detecting an eye movement of the eye based on the optical path length and the eye velocity.

A laser sensor for detecting a particle density includes: a laser configured to emit a measurement beam, an optical arrangement being arranged to focus the measurement beam to a measurement volume, the optical arrangement having a numerical aperture with respect to the measurement beam, a detector configured to determine a self-mixing interference signal of a optical wave within a laser cavity of the laser, and an evaluator. The evaluator is configured to: receive detection signals generated by the detector in reaction to the determined self-mixing interference signal, determine an average transition time of particles passing the measurement volume in a predetermined time period based on a duration of the self-mixing interference signals generated by the particles, determine a number of particles based on the self-mixing interference signals in the predetermined time period, and determine the particle density based on the average transition time and the number of particles.

A laser arrangement includes a laser array including a multitude of lasers and an optical device configured to provide a defined illumination pattern in a defined field-of-view. The optical device includes a multitude of localized optical structures, each respective localized optical structure being associated with at least one respective laser of the laser array and being arranged to redirect laser light emitted by the at least one respective laser such that laser light emitted by the at least one respective laser appears to be emitted from at least one apparent position of the laser array. The localized optical structures are arranged such that laser light emitted by at least one respective selected laser appears to be emitted from at least two apparent positions of the laser array. The optical device is arranged such that the apparent positions are distributed in an irregular pattern.

A method of forming an electrical metal contact within a semiconductor layer stack of a vertical cavity surface emitting laser includes forming a contact hole into the semiconductor layer stack. The contact hole has a bottom and a side wall extending from the bottom. The method further includes providing a photoresist mask inside the contact hole. The photoresist mask covers the side wall of the contact hole and has an opening extending to the bottom of the contact hole. The method additionally includes wet-chemical isotropic etching the bottom of the contact hole, depositing a metal on the bottom of the contact hole, and removing the photoresist mask so that the metal on the bottom of the contact hole is left as the electrical metal contact.

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.