Abstract: A light emitting device has a first mirror; and one or more active regions with a first active region adjacent to the first mirror. Each of active region includes quantum wells and barriers, and is surrounded by one or more p-n junctions. The active regions have a selected shape structure each with a tunnel junction (TJ). One or more apertures are provided with the selected shape structure; one or more buried tunnel junctions (BTJ), additional TJ's, planar structures and/or additional BTJ's, created during a regrowth process that is independent of a first growth process of the first mirror as well as the active region and the one or more TJs. One or more electrical confinement apertures are defined by the one or more BTJ's, additional TJ's, planar structures and/or additional BTJ's. A vertical resonator cavity is disposed over the electrical confinement aperture. A high contrast grating (HCG) operates as a second mirror positioned over the vertical resonator cavity.

Abstract: An electronic device is provided. The electronic device includes a substrate, a semiconductor unit, a wall, and a light-transmitting member. The semiconductor unit is mounted on the substrate. The wall is disposed on the substrate and surrounds the semiconductor unit. The wall includes two exterior wall components and two interior wall components. The two exterior wall components are spaced apart from each other, so that two gaps are formed between the two exterior wall components. The two gaps are in spatial communication with an installation area that is surrounded by the two exterior wall components. The two interior wall components are arranged in the installation area and spaced apart from each other. The two interior wall components correspond in position to the two gaps and respectively shade parts of the two gaps. The light-transmitting member is disposed on the wall and covered on the semiconductor unit.

Abstract: A light-emitting device includes a first base member; a laser unit provided on the first base member; a capacitive element that is provided on the first base member and supplies a driving electric current to the laser unit; a wiring board that is constituted by a second base member having lower thermal conductivity than the first base member and on which the first base member is mounted; and a driving unit that is mounted on the wiring board and drives the laser unit.

Abstract: An apparatus includes a light source operable to produce light having a wavelength, an optical component disposed over the light source so as to intersect a path of light produced by the light source, and at least one electrically conductive trace on a surface of the optical component. A drive controller is operable to regulate optical output power of the light source. The at least one electrically conductive trace is coupled electrically to the drive controller, which is operable to monitor an electrical characteristic of the at least one electrically conductive trace, and to reduce the optical output power of the light source if a value of the electrical characteristic is indicative of a possible eye-safety hazard.

Abstract: The present invention discloses a VCSEL array that can function in at least two different operational modes. In one operational mode, the VCSEL array functions as a regular-patterned array; and in the other operational mode, the VCSEL array functions as an irregular-patterned array. Thus, the same VCSEL chip may be used as an illumination light source or a structural light method light source for 3D sensing, depending on the selected operational mode.

Abstract: In an embodiment a radiation emitting semiconductor chip includes a semiconductor layer sequence with a plurality of active regions and a main extension plane, wherein each active region has a main extension direction, wherein each active region is configured to emit electromagnetic radiation from an emitter region extending parallel to the main extension plane, wherein at least two active regions overlap in plan view, wherein the emitter regions are arranged at grid points of a regular grid connected by at least one grid line, and wherein the main extension direction of at least one active region encloses an angle of at least 10° and at most 80° with the grid lines of the regular grid.

Abstract: A method for image generation, preferably including: generating a set of mission parameters for a UAV mission of the UAV associated with aerial scanning of a region of interest; controlling the UAV to perform the mission; generating an image subassembly corresponding to the mission; and/or rendering the image subassembly at a display.

Abstract: An optical device includes a light source provided with a plurality of surface-emitting laser elements to emit a laser beam, a scanner to scan the laser beam emitted from the light source, and an optical system disposed in an optical path between the light source and the scanner and to guide the laser beam to the scanner. The optical system includes a first optical element to control a divergence angle of the laser beam emitted from the light source and a second optical element to concentrate the laser beam that has passed through the first optical element onto a to-be-scanned surface of the scanner.

Abstract: A semiconductor laser diode is specified, the semiconductor laser diode includes a semiconductor layer sequence having an active layer having a main extension plane and which, in operation, is configured to generate light in an active region and emit light via a light-outcoupling surface, the active region extending from a back surface opposite the light-outcoupling surface to the light-outcoupling surface along a longitudinal direction in the main extension plane, the semiconductor layer sequence having a surface region on which a first cladding layer is applied in direct contact, the first cladding layer having a transparent material from a material system different from the semiconductor layer sequence, and the first cladding layer being structured and having a first structure.

Abstract: A light projection system includes a light source configured to emit image light and an optical assembly configured to provide positive optical power to the image light and optically correct the image light. The optical assembly comprises a plurality of optical elements configured to correct differential distortion related to the image light across a field of view (FOV) within a threshold amount. The differential distortion is corrected based in part on asymmetry of the plurality of optical elements relative to an optical axis shared by the plurality of optical elements.

Abstract: A plurality of light sources such as vertical-cavity surface-emitting lasers (VCSELs) are configured to emit non-visible light through emission apertures. Optics are formed over the emission apertures of the plurality of light sources. The optics may provide different tilt angles or divergence angles to the non-visible light emitted by the light sources in the plurality of light sources.

Abstract: A write head includes an input coupler configured to receive light excited by a light source. A waveguide core is configured to receive light from the input coupler at a fundamental transverse electric (TE00) mode. The waveguide core has a first straight portion. The waveguide core has a mode converter portion comprising a branched portion extending from the first straight portion. The mode converter portion is configured to convert the light to a higher-order (TE10) mode, the mode converter portion spaced apart from the input coupler. The waveguide core has a second straight portion between the mode converter portion and a media-facing surface. The write head has a near-field transducer at the media-facing surface, the near-field transducer receiving the light at the TE10 mode from the waveguide and directing surface plasmons to a recording medium in response thereto.

Abstract: Embodiments of the disclosure pertain to a system for transferring an optical signal from one photonics chip or integrated circuit (PIC) to another. The system includes a first PIC having (i) an optical emitter or optical transmission mechanism and (ii) a focusing mirror thereon, and a second PIC having an optical receiver and a reflecting mirror thereon. The reflecting mirror is configured to reflect light transmitted by the optical emitter or optical transmission mechanism back to the first PIC. The focusing mirror is configured to (i) further reflect the light reflected by the reflecting mirror and (ii) focus the further reflected light on the optical receiver. Methods of using and manufacturing the system are also disclosed.

Abstract: A light emitting device is provided including a switching element. The light emitting device includes a light emitting unit having a plurality of nanostructures that can emit lights with injection of currents, and a transistor provided in correspondence with the light emitting unit and controlling amounts of the currents injected in the nanostructures.

Abstract: Provided is a mask changing unit for a laser bonding apparatus, and more particularly, a mask changing unit for a laser bonding apparatus, wherein the mask changing unit supplies or changes a mask to or in the laser bonding apparatus for bonding a semiconductor chip to a substrate by using a laser beam. The mask changing unit for a laser bonding apparatus, a plurality of masks that are used in performing laser bonding of a semiconductor chip to a substrate while the semiconductor chip is being pressed may be easily supplied to the laser bonding apparatus or changed in the laser bonding apparatus.

Abstract: A semiconductor laser diode is specified, the semiconductor laser diode includes a semiconductor layer sequence having an active layer which has a main extension plane and which, in operation, is adapted to generate light in an active region and to emit light via a light-outcoupling surface, the active region extending from a rear surface opposite the light-outcoupling surface to the light-outcoupling surface along a longitudinal direction in the main extension plane, the semiconductor layer sequence having a surface region on which a first cladding layer is applied in direct contact, the first cladding layer having a transparent material from a material system different from the semiconductor layer sequence, and the first cladding layer being structured and having a first structure.

Abstract: A corrected mesa structure for a VCSEL device is particularly configured to compensate for variations in the shape of the created oxide aperture that result from anisotropic oxidation. In particular, a corrected mesa shape is derived by determining the shape of an as-created aperture formed by oxidizing a circular mesa structure, and then ascertaining the compensation required to convert the as-created shape into a desired (“target”) shaped aperture opening. The compensation value is then used to modify the shape of the mesa itself such that a following anisotropic oxidation yields a target-shaped oxide aperture.

Abstract: 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 ?/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 ?/+? 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%.

Abstract: A near-eye display apparatus is configured to be disposed in front of at least one eye of a user and includes an illumination system, a display device, and a micro-lens array. The illumination system is configured to provide an illumination beam including sub-illumination beams. The display device is located on a transmission path of the illumination beam. The sub-illumination beams form corresponding sub-illumination regions on the display device, and the display device is configured to convert the sub-illumination beams irradiating the display device and corresponding to the sub-illumination regions into sub-image beams. An exit angle of each sub-image beam emitted from the display device is less than or equal to 20 degrees. The near-eye display apparatus provided herein is capable of eliminating stray light and characterized by good quality.

Abstract: A laser array includes a plurality of laser emitters arranged in a plurality of rows and a plurality of columns on a substrate that is non-native to the plurality of laser emitters, and a plurality of driver transistors on the substrate adjacent one or more of the laser diodes. A subset of the plurality of laser emitters includes a string of laser emitters that are connected such that an anode of at least one laser emitter of the subset is connected to a cathode of an adjacent laser emitter of the subset. A driver transistor of the plurality of driver transistors is configured to control a current flowing through the string.

Abstract: A light projection system includes a light source configured to emit image light and an optical assembly configured to provide positive optical power to the image light and optically correct the image light. The optical assembly comprises a plurality of optical elements configured to correct differential distortion related to the image light across a field of view (FOV) within a threshold amount. The differential distortion is corrected based in part on asymmetry of the plurality of optical elements relative to an optical axis shared by the plurality of optical elements.

Abstract: A laser diode includes a semiconductor structure having an n-type layer, an active region, and a p-type layer. One of the n-type and p-type layers includes a lasing aperture thereon having an optical axis oriented perpendicular to a surface of the active region between the n-type and p-type layers. First and second contacts are electrically connected to the n-type and p-type layers, respectively. The first and/or second contacts are smaller than the lasing aperture in at least one dimension. Related arrays and methods of fabrication are also discussed.

Abstract: An optoelectronic device includes a semiconductor substrate and an array of optoelectronic cells, formed on the semiconductor substrate. The cells include first epitaxial layers defining a lower distributed Bragg-reflector (DBR) stack; second epitaxial layers formed over the lower DBR stack, defining a quantum well structure; third epitaxial layers, formed over the quantum well structure, defining an upper DBR stack; and electrodes formed over the upper DBR stack, which are configurable to inject an excitation current into the quantum well structure of each optoelectronic cell. A first set of the optoelectronic cells are configured to emit laser radiation in response to the excitation current. In a second set of the optoelectronic cells, interleaved with the first set, at least one element of the optoelectronic cells, selected from among the epitaxial layers and the electrodes, is configured so that the optoelectronic cells in the second set do not emit the laser radiation.

Abstract: A mobile device includes an image sensor separated from a processing component by an open space. The image sensor includes one or more light source modules and the processing component includes one or more light sensors aligned with the one or more light source modules. Image data from the image sensor may be transmitted to the processing component via light signals exchanged between the one or more light source modules and the one or more light sensors. In some embodiments, light signals transmitted between one or more light source modules of an image sensor and one or more light sensors of the processing component are used to determine positional and angular data about the image sensor.

Abstract: An optical apparatus is provided for an optical transceiver. The optical apparatus includes an interposer, a glass lens chip bonded to the interposer, and a plurality of bottom-emitting vertical-cavity surface-emitting lasers (VCSELs) flip chipped to the interposer. Each of the bottom-emitting VCSELs is fabricated on a respective substrate, at least one bottom-emitting VCSEL is capable of emitting an optical signal having a wavelength of about 850 nm, and at least a portion of the respective substrate on which the at least one bottom-emitting VCSEL is fabricated is removed to permit the at least one bottom-emitting VCSEL to emit the optical signal having the wavelength of about 850 nm to the glass lens chip.

Abstract: A method of manufacturing a light emitting device includes: providing a light emitting device in which a first and second semiconductor laser elements are connected in series; performing a first measurement that includes supplying current to the first semiconductor laser element to measure at least one property of the first semiconductor laser element, and supplying current to the second semiconductor laser element to measure at least one property of the second semiconductor laser element; supplying current to the first and second semiconductor laser elements for a length of time; performing a second measurement that includes supplying current to the first semiconductor laser element to measure the at least one property of the first semiconductor laser element, and supplying current to the second semiconductor laser element to measure the at least one property of the second semiconductor laser element, and evaluating the first and second semiconductor laser elements.

Abstract: Techniques of minimizing or eliminating stresses in silicon photonic integrated circuits (Si-PICs) and in semiconductor packages having one or more Si-PICs (Si-PIC packages) are described. An Si-PIC or an Si-PIC package includes a stress minimization solution that assists with filtering out stresses by selectively isolating photonic and/or electronic devices, by isolating components or devices in an Si-PIC or an Si-PIC package that are sources of stress, or by isolating an Si-PIC in an Si-PIC package. The stress minimization solution may include strategically placed cavities and a stage that assist with minimizing or preventing transfer of stress to one or more photonic and/or electronic devices in an Si-PIC or an Si-PIC package.

Abstract: An optoelectronic device includes a semiconductor substrate and an array of optoelectronic cells, formed on the semiconductor substrate. The cells include first epitaxial layers defining a lower distributed Bragg-reflector (DBR) stack; second epitaxial layers formed over the lower DBR stack, defining a quantum well structure; third epitaxial layers, formed over the quantum well structure, defining an upper DBR stack; and electrodes formed over the upper DBR stack, which are configurable to inject an excitation current into the quantum well structure of each optoelectronic cell. A first set of the optoelectronic cells are configured to emit laser radiation in response to the excitation current. In a second set of the optoelectronic cells, interleaved with the first set, at least one element of the optoelectronic cells, selected from among the epitaxial layers and the electrodes, is configured so that the optoelectronic cells in the second set do not emit the laser radiation.

Abstract: A spectral imager, including: a photodetector including a plurality of photosensitive sites exposed on a photosensitive surface; a collimating lens including an intermediate focal plane; an array of interferometers including two main waves, each including a cavity defined by two faces; an array of microlenses arranged in a plane parallel to the photosensitive surface, each microlens paired with an interferometer to form an optical pair, including an image focal plane coinciding with the photosensitive surface and facing a section of the photosensitive surface.

Abstract: This disclosure describes an optoelectronic to provide ultra-precise and stable packaging for an optoelectronic device such as a light emitter or light detector. The module includes spacers to establish precise separation distances between various parts of the module. One of the spacers serves as a support or mount for an optical element that comprises a mask.

Abstract: A vertical cavity surface emitting laser (VCSEL) array may comprise a doped substrate layer. The VCSEL array may comprise a plurality of VCSELs on the doped substrate layer. The VCSEL array may comprise a buffer structure between the doped substrate layer and the plurality of VCSELs. The buffer structure, or a combination of the buffer structure and a layer of the plurality of VCSELs, may provide electrical isolation from the plurality of VCSELs to the doped substrate layer. The VCSEL array may comprise an isolation structure between adjacent VCSELs of the plurality of VCSELs. The isolation structure may provide electrical isolation between a first VCSEL, of the adjacent VCSELs, and a second VCSEL of the adjacent VCSELs. The first VCSEL and the second VCSEL may be different VCSELs.

Abstract: A proximity sensing module with dual transmitters includes a circuit board, a package housing, a transmitter unit and a sensing assembly. The transmitter unit includes a first transmitter and a second transmitter. The first transmitter and the second transmitter are disposed on the circuit board. The sensing assembly includes a sensor disposed on the circuit board. The transmitter unit is shielded from the sensing assembly through the package housing. One of the first transmitter and the second transmitter is nearer to the sensing assembly than the other one is.

Abstract: A highly efficient laser ignition device is provided. The highly efficient laser ignition device fundamentally includes: a pumping light source adopting a multi-chip single emitter-packaged optical fiber output laser diode; a laser medium to which ytterbium is added; and a saturated absorber as a passive Q-switch medium, wherein a pulse of 100-999 ps as the passive Q-switch laser output can be obtained. According to the disclosed, the problems of high cost/low efficiency/low reliance/non-uniformity, which are disadvantages for replacing an ignition device using an electric spark with a laser ignition device, can be solved.

Abstract: A laser array includes a plurality of laser emitters arranged in a plurality of rows and a plurality of columns on a substrate that is non-native to the plurality of laser emitters, and a plurality of driver transistors on the substrate adjacent one or more of the laser diodes. A subset of the plurality of laser emitters includes a string of laser emitters that are connected such that an anode of at least one laser emitter of the subset is connected to a cathode of an adjacent laser emitter of the subset. A driver transistor of the plurality of driver transistors is configured to control a current flowing through the string.

Abstract: Disclosed herein are light emitting diodes (LEDs) having a high efficiency. A light emitting diode including an active light emitting layer within a semiconductor layer is provided. The semiconductor layer has a mesa shape. The light emitting diode also includes a substrate having a first surface on which the semiconductor layer is positioned and an outcoupling surface opposite to the first surface. Light generated by the active light emitting layer is incident on the outcoupling surface and propagates toward an optical element downstream of the outcoupling surface. The light emitting diode also includes a first anti-reflection coating adjacent to the outcoupling surface; an index-matched material between the outcoupling surface and the optical element, wherein an index of refraction of the index-matched material is greater than or equal to an index of refraction of the optical element; and/or secondary optics adjacent to the outcoupling surface.

Abstract: A semiconductor laser device of an embodiment comprises: a first electrode having an opening for passage of laser light and arranged on a main surface of a substrate; and a second electrode arranged on a back surface of the substrate. A stacked structural body including an active layer and a photonic crystal layer is arranged between the substrate and the first electrode, and a current confinement layer having an opening for passage of a current is arranged between the stacked structural body and the first electrode. A maximum width of the opening of the current confinement layer is smaller than a maximum width of the opening of the first electrode, and a whole region defined by the opening of the current confinement layer fits within a region defined by the opening of the first electrode as viewed from the first electrode side toward the second electrode side.

Abstract: Photonic devices such as semiconductor lasers and photodetectors of various operating wavelengths are grown monolithically on a Silicon substrate, and formed of nanowire structures with quantum structures as active regions. A reduction of strain during fabrication results from the use of these nanowire structures, thereby allowing devices to operate for extended periods of time at elevated temperatures. Monolithic photonic devices and monolithic photonic integrated circuits formed on Silicon substrates are thus provided.

Abstract: An example device in accordance with an aspect of the present disclosure includes a slab to transmit light, and a plurality of lenses and filters disposed on first and second surfaces of the slab. The lenses include an anti-reflective coating on at least one of the plurality of lenses at an end of the slab to couple light through the anti-reflective coating, and a reflective coating disposed on remaining ones of the plurality of lenses to cause the lenses to reflect light. The filters are offset from the lenses to form an optical zig-zag.

Abstract: Optical systems and methods for collecting distance information are disclosed. An example optical system includes a bulk receiving optic, a plurality of illumination sources, a pixel array comprising at least a first column of pixels and a second column of pixels, each pixel in the first column of pixels being offset from an adjacent pixel in the first column of pixels by a first pixel pitch, the second column of pixels being horizontally offset from the first column of pixels by the first pixel pitch, the second column of pixels being vertically offset from the first column of pixels by a first vertical pitch; and a set of input channels interposed between the bulk receiving optic and the pixel array.

Abstract: An organic light emitting diode (OLED) having an organic electroluminescent layer formed between a first electrode and a second electrode. One of the first and second electrodes is a transparent electrode having a surface through which light is emitted from the OLED to the outside. The transparent electrode has a plasmonic photonic crystal structure fabricated having an artificial lattice with a pitch in density variation intermediate in size between a metallic crystal and a photonic crystal formed in the same material as the transparent electrode, thereby operable to suppress propagation of the surface plasmon polaritons at the surface.

Abstract: A vertical cavity surface emitting laser (VCSEL) array may comprise a doped substrate layer. The VCSEL array may comprise a plurality of VCSELs on the doped substrate layer. The VCSEL array may comprise a buffer structure between the doped substrate layer and the plurality of VCSELs. The buffer structure, or a combination of the buffer structure and a layer of the plurality of VCSELs, may provide electrical isolation from the plurality of VCSELs to the doped substrate layer. The VCSEL array may comprise an isolation structure between adjacent VCSELs of the plurality of VCSELs. The isolation structure may provide electrical isolation between a first VCSEL, of the adjacent VCSELs, and a second VCSEL of the adjacent VCSELs. The first VCSEL and the second VCSEL may be different VCSELs.

Abstract: A structure includes an optoelectronic device having a Group IV substrate (e.g., Si); a buffer layer (e.g. SiGe) disposed on the substrate and a first distributed Bragg reflector (DBR) disposed on the buffer layer. The first DBR contains alternating layers of doped Group IV materials (e.g., alternating layers of SiyGe(1?y), where 0.8<y<1, and SizGe(1?z), where 0.2<z<0.4) that are substantially transparent to a wavelength of interest. The structure further includes a strained layer of a Group III-V material over the first DBR and a second DBR over the strained layer. The second DBR contains alternating layers of electrically conductive oxides (e.g., ITO/AZO) that are substantially transparent to the wavelength of interest. Embodiments of VCSELs and photodetectors can be derived from the structure. The strained layer of Group III-V material can be, for example, a thin layer of In0.53Ga0.47As having a thickness in a range of about 2 nm to about 5 nm.

Abstract: The present application relates to vertically integrated assemblies including a MEMS-based optomechanical architecture. In some embodiments, the assembly includes a MEMS/optoelectronic module, an emitter module, and a detector module, where these modules are vertically integrated. Methods of fabricating such assemblies are also described herein.

Abstract: A surface-emitting semiconductor laser system contains at least one MQW unit of at least three constituent QWs, axially separated from one another substantially non-equidistantly. The MQW unit is located within the axial extent covered, in operation of the laser, by a half-cycle of the standing wave of the field at a wavelength within the gain spectrum of the gain medium; immediately neighboring nodes of the standing wave are on opposite sides of the MQW unit. So-configured MQW unit can be repeated multiple times and/or complemented with individual QWs disposed outside of the half-cycle of the standing wave with which such MQW unit is associated. The semiconductor laser further includes a pump source configured to input energy in the semiconductor gain medium and a mode-locking element to initiate mode-locking.

Abstract: A quantum cascade laser is configured with a semiconductor substrate, and an active layer provided on a first surface of the substrate and having a multistage lamination of unit laminate structures each of which includes an emission layer and an injection layer. The active layer is configured to be capable of generating first pump light of a frequency ?1 and second pump light of a frequency ?2, and to generate output light of a difference frequency ? by difference frequency generation. An external diffraction grating is provided constituting an external cavity for generating the first pump light and configured to be capable of changing the frequency ?1, outside an element structure portion including the active layer. Grooves respectively formed in a direction intersecting with a resonating direction are provided on a second surface of the substrate.

Abstract: Certain examples described herein relate to a surface-emitting semiconductor-laser which includes an oxide window, a light emitting cavity, and at least one phase matching window. The oxide window, the light emitting cavity, and the at least one phase matching layer are arranged so that a predetermined phase relationship is satisfied. The phase relationship facilitates high performance and stable multimode operations of the surface-emitting semiconductor laser designed to emit between 850-1060 nm wavelength for applications such as long distance optical communications in high performance computing and data servers.

Abstract: A photoelectric conversion connector comprising a support, a photoelectric conversion element that is provided on said support and that can be connected to an optical fiber through an optical signal, a first resin member that is formed at the upper part of the photoelectric conversion element, and a second resin member that is formed at the upper part of the first resin member. An optical signal transmitted between the photoelectric conversion element and the optical fiber goes through both the first resin member and the second resin member.

Abstract: The disclosure is directed at a method and apparatus for producing a detector element. The detector element includes first and second electrodes located on opposites sides of a semiconductor layer. The first and second electrodes are staggered with respect to each other in a plane perpendicular to the semiconductor layer.

Abstract: An optoelectronic device comprises microwires or nanowires, each of which comprises an alternation of passivated portions and of active portions, the active portions being surrounded with an active layer, where the active layers do not extend on the passivated portions.

Abstract: An imaging system color image acquisition including: an image sensor; a tunable spectral filter arranged in an optical path of light propagation towards the image sensor; and a controller connected to the image sensor and to the tunable spectral filter. The controller is configured and operable for generating a colored image by sequentially operating the tunable spectral filter for sequentially filtering light passing towards the image sensor with three or more different spectral filtering curves during three or more corresponding integration time durations. The tunable spectral filter is configured, as an etalon and includes a pair of reflective surfaces. At least one of the reflective surfaces includes a layer of high refractive index of at least n=2.3 or even higher than 3, or a layer of low refractive index, smaller than n=1.