Abstract: The invention relates to a method for the sequential measurement of a plurality of semiconductor-based light sources such as LEDs, OLEDs or VCSELs, in particular comparatively low-luminosity light sources such as so-called micro-LEDs. The invention further relates to a device for carrying out the method. The object of the present invention is to provide a method that operates faster, more accurately and more sensitively than the known methods, which operate by scanning with a photodiode or with a spectrometer. The method according to the invention proposes for this that a current pulse is applied by means of a pulsed current source (1) to the low-luminosity light sources consecutively or simultaneously.

Abstract: A method for two-dimensional, spatially resolved measurement of tristimulus values of light emitted from a plurality of positions on a sample. In various embodiments, an improved method and system is provided for spatially resolved chromaticity and luminance measurement in a standardized color space for display testing. The method may include directing a first portion of the light to an RGB camera which produces a two-dimensional map of RGB color values; transforming the RGB color values into first tristimulus values to produce a map of tristimulus values; directing a second portion of the light to a colorimeter which produces second tristimulus values; deriving a tristimulus correction by comparing the second tristimulus values with at least a subset of the first tristimulus values; and applying the tristimulus correction to the first tristimulus values to produce a corrected map of tristimulus values.

Abstract: A colorimeter with multiple sensings of light to provide higher accuracy measurements of the primaries of a human-standard observer based color space is provided. This color space (target color space) must have the characteristic of two chromaticity coordinates and an achromatic primary like CIELAB, CIELUV or xyY in CIE 1931. The calibration of the device includes training with a set of calibration illuminants. Two sets of calibration-factors are determined. The first set of calibration factors yields intensity of primaries optimized with respect to chromaticity, the second set yields the optimized intensity of the achromatic primary. The combination of these sets of calibration factors enable the colorimeter to deliver values of that light with respect to three primaries of a human-standard-observer-based color space optimized with respect to chromaticity and the achromatic primary.

Abstract: The invention relates to a fiber laser comprising a ring-shaped resonator (3). A first section of the resonator is formed by an optical fiber (7) while a second section of the resonator is formed by an optically pumped amplifier fiber (8). The fiber laser further comprises an injection point (4) for injecting light of a pump light source (1) into the resonator (3) as well as an extraction point (5) for extracting generated laser light from the resonator (3). The aim of the invention is to design a more developed fiber laser. The aim is achieved by providing the resonator (3) with at least one reflective optical component (12, 51) which reflects the laser light circulating in the resonator (3).

Abstract: The invention relates to a fiber laser comprising a ring-shaped resonator (3). A first section of the resonator is formed by an optical fiber (7) while a second section of the resonator is formed by an optically pumped amplifier fiber (8). The fiber laser further comprises an injection point (4) for injecting light of a pump light source (1) into the resonator (3) as well as an extraction point (5) for extracting generated laser light from the resonator (3). The aim of the invention is to design a more developed fiber laser. The aim is achieved by providing the resonator (3) with at least one reflective optical component (12, 51) which reflects the laser light circulating in the resonator (3).

Abstract: A passively mode-locked optically pumped semiconductor vertical-external-cavity surface-emitting laser (OPS-EXSEL) is disclosed. The laser is mode locked by a semiconductor saturable absorber mirror (SESAM) which forms part of an external cavity. Both the beam-quality limitations of edge-emitting lasers, and the power restrictions of electrically pumped surface-emitting lasers are overcome. The laser uses a semiconductor wafer in which a stack of quantum wells is grown adjacent to a single Bragg-mirror structure. Light from one or more multi-mode high-power diode lasers is focused onto the face of the wafer and pumps the wells by absorption in the barrier regions. The area of the laser mode on the active mirror can be about 104 times larger than the mode area on the facet of an edge-emitting laser, offering scope for the generation of high average power and large pulse energy. At the same time the external cavity enforces fundamental mode operation in a circular, near-diffraction-limited beam.