Abstract: Laser devices include a light source that emits a laser beam, an optical system that concentrates the laser beam emitted from the light source, an optical window through which the laser beam exited from the optical system passes, a housing that accommodates the optical system, and an optical window holding member fixed to the housing. The optical window holding member holds the optical window. In the first laser device, the optical window has a face or a protruding face through which the laser beam passes. When the optical window has the face, the face is flush with an edge of the optical window holding member and a film is formed on the face. When the optical window has the protruding face, the protruding face protrudes with reference to the edge of the optical window holding member and a film is formed on the protruding face.

Abstract: A surface-emitting laser includes an active layer on which a spacer layer is disposed, and a reflection mirror disposed on the spacer layer, including a current constriction layer that is a selectively-oxidized layer having been selectively oxidized. The current constriction layer is disposed at a position of a node of a standing-wave of an electric field of light oscillated at the active layer and is disposed away from an interface between the spacer layer and the reflection mirror by an optical distance of one-fourth of an oscillation wavelength at the active layer. The selectively-oxidized layer is made of AlGaAs. The reflection mirror includes at least one AlGaInP layer contacting the selectively-oxidized layer.

Abstract: Laser devices include a light source that emits a laser beam, an optical system that concentrates the laser beam emitted from the light source, an optical window through which the laser beam exited from the optical system passes, a housing that accommodates the optical system, and an optical window holding member fixed to the housing. The optical window holding member holds the optical window. In the first laser device, the optical window has a face or a protruding face through which the laser beam passes. When the optical window has the face, the face is flush with an edge of the optical window holding member and a film is formed on the face. When the optical window has the protruding face, the protruding face protrudes with reference to the edge of the optical window holding member and a film is formed on the protruding face.

Abstract: An optical window member includes an incident surface onto which a laser light is directed and an exit surface from which the laser light exits. At least one of the incident surface and the exit surface has a plurality of protrusions or recesses formed therein. An interval between centers of adjacent protrusions or adjacent recesses is shorter than or equal to a wavelength of the laser light.

Abstract: A surface-emitting laser includes an active layer on which a spacer layer is disposed, and a reflection mirror disposed on the spacer layer, including a current constriction layer that is a selectively-oxidized layer having been selectively oxidized. The current constriction layer is disposed at a position of a node of a standing-wave of an electric field of light oscillated at the active layer and is disposed away from an interface between the spacer layer and the reflection mirror by an optical distance of one-fourth of an oscillation wavelength at the active layer. The selectively-oxidized layer is made of AlGaAs. The reflection mirror includes at least one AlGaInP layer contacting the selectively-oxidized layer.

Abstract: A surface-emitting laser includes a plurality of semiconductor layers; an active layer; and spacer layers, between which the active layer is held. The active layer includes a first layer including aluminum gallium indium arsenide ((AlxGa1-x)yIn1-yAs, where x and y are greater than or equal to zero but less than one), and a second layer including aluminum gallium indium arsenide ((AlmGa1-m)nIn1-nAs, where m and n are greater than or equal to zero but less than one, and at least one of m-x and n-y is not zero). The spacer layers includes aluminum gallium indium phosphide ((AlaGa1-a)bIn1-bP, where a and b are greater than or equal zero but less than one). The plurality of semiconductor layers and the active layer held between the spacer layers are laminated.