A light source structure includes a vertical cavity surface-emitting laser (VCSEL) device having a top surface and at least one side surface substantially perpendicular to and adjoining the top surface. The VCSEL device is configurable to output directed emission of light through the top surface. The light source structure also includes a light barrier surrounding at least a top portion of the VCSEL device and separated from the at least one side surface. The light barrier is configured to receive spontaneous emission out of the VCSEL device through the at least one side surface.

Apparatus and methods that enable the suppression of amplified spontaneous emission (ASE) and prevention against parasitic lasing in cryogenically-cooled laser amplifier systems, thus allowing sustainable extraction efficiency when increasing the pump power and suitable for large-scale, high average-power laser systems employing large-aperture gain media. A gain medium having a known index of refraction for operation in an evacuated, cryogenic environment includes an ASE-absorbing epoxy composition on the perimetrical edge of the gain medium, wherein the epoxy composition has an index of refraction that substantially matches the index of refraction of the gain medium.

Apparatus and methods that enable the suppression of amplified spontaneous emission (ASE) and prevention against parasitic lasing in cryogenically-cooled laser amplifier systems, thus allowing sustainable extraction efficiency when increasing the pump power and suitable for large-scale, high average-power laser systems employing large-aperture gain media. A gain medium having a known index of refraction for operation in an evacuated, cryogenic environment includes an ASE-absorbing epoxy composition on the perimetrical edge of the gain medium, wherein the epoxy composition has an index of refraction that substantially matches the index of refraction of the gain medium.

A laser light source, comprising a semiconductor layer sequence having an active region and a radiation coupling out area having first and second partial regions, and a filter structure. The active region generates coherent first electromagnetic radiation and incoherent second electromagnetic radiation. The coherent first electromagnetic radiation is emitted by the first partial region along an emission direction, and the incoherent second electromagnetic radiation is emitted by the first partial region and by the second partial region. The filter structure at least partly attenuates the incoherent second electromagnetic radiation emitted by the active region along the emission direction. The filter structure comprises at least one first filter element disposed downstream of the semiconductor layer sequence in the emission direction and it has at least one layer comprising a material that is non-transparent to electromagnetic radiation.

A laser light source, comprising a semiconductor layer sequence having an active region and a radiation coupling out area having first and second partial regions, and a filter structure. The active region generates coherent first electromagnetic radiation and incoherent second electromagnetic radiation. The coherent first electromagnetic radiation is emitted by the first partial region along an emission direction, and the incoherent second electromagnetic radiation is emitted by the first partial region and by the second partial region. The filter structure at least partly attenuates the incoherent second electromagnetic radiation emitted along the emission direction. The filter structure has at least one filter element arranged on an area of the semiconductor layer sequence which has an extension direction parallel to the emission direction. The at least one filter element comprises a surface structure comprising a roughening and/or at least one layer comprising a non-transparent material.

An optical amplifier includes a plurality of photon amplifying regions. Each photon amplifying region includes a bottom electrode, an insulating layer formed over the bottom electrode, and having a through hole to the bottom electrode, a semiconductor layer and a top electrode formed over the semiconductor layer, wherein the top and bottom electrodes electrically contact the semiconductor layer. The semiconductor layer is formed over the insulating layer and in the through hole, and has a semiconductor active region in the through hole. The semiconductor active region has a direct electronic band gap with a conduction band edge, and is embedded within a photonic crystal having an electromagnetic band gap having photon energies overlapping the energy of the conduction band edge of the electronic band gap such that spontaneous emission of photons in the semiconductor active region is suppressed.

The present invention relates to a method for obtaining an n-type doped metal chalcogenide quantum dot solid-state element with optical gain for low-threshold, band-edge amplified spontaneous emission (ASE), comprising: forming a metal chalcogenide quantum dot solid-state element, and carrying out an n-doping process on its metal chalcogenide quantum dots to at least partially bleach its band-edge absorption, which comprises: a partial substitution of chalcogen atoms by halogen atoms, in the metal chalcogenide quantum dots, and/or a partial aliovalent-cation substitution of bivalent metal cations by trivalent cations, in the metal chalcogenide quantum dots; and providing a substance on the metal chalcogenide quantum dots, to avoid oxygen p-doping. The present invention also relates to the obtained n-type doped metal chalcogenide quantum dot solid-state element, a method for obtaining a light emitter with that n-type doped metal chalcogenide quantum dot solid-state element, and the obtained light emitter.