An illumination system (200) includes an illumination device (202); an optical element (206) positioned to receive light (208) from the illumination device (202); a layer (210) of a transparent material disposed on the optical element (206) and positioned to receive light (208) from the illumination device (202); and an interlock circuit (220) configured to measure a resistivity of the layer (210) of transparent material and to control operation of the illumination device (202) based on the measured resistivity.

A wavelength filter includes a first filter circuit and a second filter circuit. The first filter circuit that has a passband that is obtained from a vernier effect by connecting, in series, a plurality of ring resonators each having a different transmission wavelength interval and that is within a gain band of an optical amplifier, and that passes, from the gain band, light at a selected wavelength and light that has a wavelength in a recursive mode and that is produced on a short wavelength side or a long wavelength side of the selected wavelength. The second filter circuit is connected to the first filter circuit in series and suppresses the light at the wavelength in the recursive mode from the light passing through the first filter circuit.

A light-emitting element includes: a laminated structure body 20 which is formed from a GaN-based compound semiconductor and in which a first compound semiconductor layer 21 including a first surface 21a and a second surface 21b that is opposed to the first surface 21a, an active layer 23 that faces the second surface 21b of the first compound semiconductor layer 21, and a second compound semiconductor layer 22 including a first surface 22a that faces the active layer 23 and a second surface 22b that is opposed to the first surface 22a are laminated; a first light reflection layer 41 that is provided on the first surface 21a side of the first compound semiconductor layer 21; and a second light reflection layer 42 that is provided on the second surface 22b side of the second compound semiconductor layer 22. The first light reflection layer 41 includes a concave mirror portion 43, and the second light reflection layer 42 has a flat shape.

A VCSEL may include an n-type substrate layer and an n-type bottom mirror on a surface of the n-type substrate layer. The VCSEL may include an active region on the n-type bottom mirror and a p-type layer on the active region. The VCSEL may include an oxidation layer over the active region to provide optical and electrical confinement of the VCSEL. The VCSEL may include a tunnel junction over the p-type layer to reverse a carrier type of an n-type top mirror. Either the oxidation layer is on or in the p-type layer and the tunnel junction is on the oxidation layer, or the tunnel junction is on the p-type layer and the oxidation layer is on the tunnel junction. The VCSEL may include the n-type top mirror over the tunnel junction, a top contact layer over the n-type top mirror, and a top metal on the top contact layer.

A laser module includes: a laser diode bar including a plurality of emitters configured to emit laser light from a front surface and leak light from a rear surface; a housing including a reflecting surface configured to surround a space together with the laser diode bar and reflect, toward the space, light leaked from the rear surface, in a scattering manner; and a detector configured to detect light reflected by the reflecting surface. A laser module includes: a laser diode bar including a plurality of emitters configured to emit laser light from a front surface and leak light from a rear surface; a condenser lens on which light leaked from rear surfaces of all of the plurality of emitters impinges; and a detector configured to detect light transmitted through the condenser lens.

An on-chip integrated semiconductor laser structure and a method for preparing the same. The structure includes: an epitaxial structure including a first N contact layer, a first N confinement layer, a first active region, a first P confinement layer, a first P contact layer, an isolation layer, a second N contact layer, a second N confinement layer, a second active region, a second P confinement layer, and a second P contact layer sequentially deposited on a substrate; a first waveguide and a second waveguide; a first optical grating and a second optical grating; and current injection windows.

A laser sensor includes a laser source configured to emit a laser beam, and optics configured to project the laser beam as a one- or two-dimensional patterned laser beam onto an object to be examined, such that a distance of the patterned laser beam from the laser source varies along the patterned laser beam projected on the object. The laser sensor further includes a detector configured to determine a self-mixing interference signal generated by laser light of the patterned laser beam reflected from the object back into the laser source, and circuitry configured to analyze a spectrum of the self-mixing interference signal and extract from the spectrum of the self-mixing interference signal multiple frequencies that are indicative of at least one of the following: multiple distances along the patterned laser beam from the laser source, or multiple velocities along the patterned laser beam with respect to the laser source.

In at least one embodiment, the optoelectronic semiconductor device comprises a carrier, a first semiconductor laser configured to emit a first laser radiation and applied on the carrier, and a multi-mode waveguide configured to guide the first laser radiation and also applied on the carrier, wherein the multi-mode waveguide comprises at least one furcation and a plurality of branches connected by the at least one furcation.

The invention provides a light generating device (1000) configured to generate device light (1001), wherein the light generating device (1000) comprises (i) a first light source (110) configured to generate blue first light source light (111), wherein the first light source (110) is a first laser light source (10), (ii) a first luminescent material (210) configured to convert part of the blue first light source light (111) into first luminescent material light (211) having an emission band having wavelengths in one or more of the green and yellow, (iii) an optical filter (410) configured to optically filter the first luminescent material light (211) into optically filtered first luminescent material light (213), whereby the optically filtered first luminescent material light (213) is red-shifted relative to the first luminescent material light (211), and (iv) a second light source (120) configured to generate red second light source light (121), wherein the second light source (120) comprises a second laser light source (20); wherein in one or more operational modes of the light generating device (1000) the light generating device (1000) is configured to generate white device light (1001) comprising the first light source light (111), the optically filtered first luminescent material light (213), and the second light source light (121).

An information processing device includes a processor and a storage device. The processor is configured to acquire data for each parameter provided from each of a light source device which generates pulse light and an exposure apparatus which performs exposure on a wafer with the pulse light output from the light source device, and time data associated with the data; to perform classification, based on the acquired data and time data, for each record of the data associated with same time data for distinguishing whether being data during exposure in which the wafer is irradiated with the pulse light or being data during non-exposure; to associate attribute information indicating an attribute according to the classification with each of the records; to cause the storage device to store the data and the time data associated with the attribute information; and to generate a chart using data read from the storage device.