Abstract: A quantum cascade laser element includes: a semiconductor substrate; a semiconductor laminate formed on the semiconductor substrate to include an active layer having a quantum cascade structure and to have a first end surface and a second end surface facing each other in a light waveguide direction; a first electrode; a second electrode; an insulating film continuously formed from the second end surface to a region on a second end surface side of at least one surface of a surface on an opposite side of the first electrode from the semiconductor laminate and a surface on an opposite side of the second electrode from the semiconductor substrate; and a metal film formed on the insulating film to cover at least the active layer when viewed in the light waveguide direction. An outer edge of the metal film does not reach the one surface when viewed in the light waveguide direction.

Abstract: A quantum cascade laser device includes a QCL element; a lens; and a lens holder having a small-diameter hole, a large-diameter hole, and a counterbore surface. At least a part of a side surface of the lens is fixed to an inner surface of the large-diameter hole in a state where an edge portion of an incident surface of the lens is in contact with the counterbore surface. A central axis of the small-diameter hole is eccentric from that of the large-diameter hole. The side surface of the lens is positioned with respect to the inner surface of the large-diameter hole along a direction from the central axis of the large-diameter hole toward the central axis of the small-diameter hole. A central axis of the lens is disposed at a position closer to the central axis of the small-diameter hole than to the central axis of the large-diameter hole.

Abstract: The laser module includes a QCL element, a diffraction grating unit, a first lens holder, a second lens holder, and a mount member. The first mounting portion has a first top surface on which the first lens holder is mounted via an adhesive layer. The third mounting portion has a third top surface on which the second lens holder is mounted via an adhesive layer. The second mounting portion has a second top surface located higher than the first top surface and the third top surface, a first side surface connecting the second top surface and the first top surface, and a second side surface connecting the second top surface and the third top surface. A notch extending from the second top surface to the first top surface or the third top surface is formed in at least one of the first side surface and the second side surface.

Abstract: The laser module includes a QCL element, a MEMS diffraction grating, a first lens holder disposed on a side opposite to a side on which the MEMS diffraction grating is disposed with respect to the QCL element, a second lens holder disposed between the QCL element and the MEMS diffraction grating, a package, an electrode terminal disposed along an inner wall surface of the package, and a wire for electrically connecting the electrode terminal and the QCL element. An end portion of the wire on a side where the QCL element is disposed is disposed at a position between the first lens holder and the second lens holder when viewed from a direction orthogonal to a facing direction in which the first lens holder and the second lens holder face each other.

Abstract: The laser module includes a QCL element, a MEMS diffraction grating, a lens holder for holding a lens disposed between the QCL element and the MEMS diffraction grating, and a package. The package includes a bottom wall, a side wall erected on the bottom wall and formed in an annular shape so as to surround a region in which the QCL element is accommodated, and a top wall closing an opening of the side wall on a side opposite to a side where the bottom wall is disposed. The top wall faces the bottom wall in a direction orthogonal to the optical axis direction of the lens, and the distance between the top wall and a surface of the lens holder on a side where the top wall is disposed is smaller than a thickness of the lens holder along the optical axis direction of the lens.

Abstract: The laser module includes a QCL element, a MEMS diffraction grating, a lens holder holding a lens disposed between the QCL element and the MEMS diffraction grating, a package, an electrode terminal disposed along an inner wall surface of the package, and a wire for electrically connecting the electrode terminal and a coil. The top wall of the package faces the bottom wall of the package in a direction orthogonal to the optical axis direction of the lens. The MEMS diffraction grating includes an electrode pad electrically connected to the coil. The electrode pad is connected to the electrode terminal via the wire. A height position of the electrode pad with respect to the bottom wall is equal to or higher than a height position of the electrode terminal with respect to the bottom wall.

Abstract: A light source module includes a light source; an optical fiber configured to guide light output from the light source; a pair of holding members configured to hold both ends of a first portion of the optical fiber such that the first portion extends linearly; a first vibrator configured to vibrate the first portion along a first direction intersecting an extending direction of the first portion; and a second vibrator configured to vibrate the first portion along a second direction intersecting the extending direction and differing from the first direction.

Abstract: A quantum cascade laser device has a light-absorbing cover member located between one emission end face of a quantum cascade laser element and an emission window of a housing. The emission end face and an opposing surface of a submount with respect to the cover member are flush with each other. The cover member has an opening at a position opposing the emission end face. The opening has a tapered first opening part increasing its diameter from the emission end face side to the emission window side and a second opening part formed with a fixed diameter not smaller than the smallest diameter of the first opening part.

Abstract: A quantum cascade laser device has a light-absorbing cover member located between one emission end face of a quantum cascade laser element and an emission window of a housing. The emission end face and an opposing surface of a submount with respect to the cover member are flush with each other. The cover member has an opening at a position opposing the emission end face. The opening has a tapered first opening part increasing its diameter from the emission end face side to the emission window side and a second opening part formed with a fixed diameter not smaller than the smallest diameter of the first opening part.

Abstract: A laser module LM is provided with a quantum cascade laser 1, a tubular member 5, and an infrared detector 7. The tubular member 5 has a pair of opening ends 5a, 5b and is arranged so that one opening end 5a is opposed to a face 1b opposed to an emitting end face 1a of the quantum cascade laser 1. The infrared detector 7 is arranged so as to be opposed to the other opening end 5b of the tubular member 5. Light emitted from the face (rear end face) 1b opposed to the emitting end face (front end face) 1a of the quantum cascade laser 1 is guided inside the tubular member 5 to enter the infrared detector 7, and then is detected.

Abstract: A laser module LM is provided with a quantum cascade laser 1, a tubular member 5, and an infrared detector 7. The tubular member 5 has a pair of opening ends 5a, 5b and is arranged so that one opening end 5a is opposed to a face 1b opposed to an emitting end face 1a of the quantum cascade laser 1. The infrared detector 7 is arranged so as to be opposed to the other opening end 5b of the tubular member 5. Light emitted from the face (rear end face) 1b opposed to the emitting end face (front end face) 1a of the quantum cascade laser 1 is guided inside the tubular member 5 to enter the infrared detector 7, and then is detected.

Abstract: A DFB quantum cascade laser element that can reliably CW-oscillate a single-mode light even at room temperature or a temperature in proximity thereof is provided. In a quantum cascade laser element 1, a top-grating approach for which a diffraction grating 7 is formed on a laminate 3 is adopted, and thus in comparison with a buried-grating approach, deterioration in temperature characteristics of the laser element and decline in the yield and reproducibility are suppressed. In addition, since the thickness of a cladding layer 5 located between an active layer 4 and the diffraction grating 7 is within a range of 42±10% of the oscillation wavelength, weakening of light seeping from the active layer 4 to the diffraction grating 7 or an increase in light leakage is prevented. Consequently, by the quantum cascade laser element 1, a single-mode light can be reliably CW-oscillated even at room temperature or a temperature in proximity thereof.

Abstract: A quantum cascade laser includes a semiconductor substrate, and an active layer which is provided on the semiconductor substrate, and has a cascade structure in which unit laminate structures 16 having quantum well emission layers 17 and injection layers 18 are laminated in multiple stages. Further, the quantum cascade laser is configured such that the unit laminate structure 16 has an emission upper level Lup, an emission lower level Llow, and a relaxation miniband MB including an energy level lower than the emission lower level in its subband level structure, and light is generated by an intersubband transition of electrons from the upper level to the lower level, and the electrons after the intersubband transition are relaxed from the lower level Llow to the miniband MB through LO phonon scattering, to be injected from the injection layer 18 to the latter stage emission layer via the miniband MB.

Abstract: A quantum cascade laser includes a semiconductor substrate, and an active layer which is provided on the semiconductor substrate, and has a cascade structure in which unit laminate structures 16 having quantum well emission layers 17 and injection layers 18 are laminated in multiple stages. Further, the quantum cascade laser is configured such that the unit laminate structure 16 has an emission upper level Lup, an emission lower level Llow, and a relaxation miniband MB including an energy level lower than the emission lower level in its subband level structure, and light is generated by an intersubband transition of electrons from the upper level to the lower level, and the electrons after the intersubband transition are relaxed from the lower level Llow to the miniband MB through LO phonon scattering, to be injected from the injection layer 18 to the latter stage emission layer via the miniband MB.

Abstract: A DFB quantum cascade laser element that can reliably CW-oscillate a single-mode light even at room temperature or a temperature in proximity thereof is provided. In a quantum cascade laser element 1, a top-grating approach for which a diffraction grating 7 is formed on a laminate 3 is adopted, and thus in comparison with a buried-grating approach, deterioration in temperature characteristics of the laser element and decline in the yield and reproducibility are suppressed. In addition, since the thickness of a cladding layer 5 located between an active layer 4 and the diffraction grating 7 is within a range of 42±10% of the oscillation wavelength, weakening of light seeping from the active layer 4 to the diffraction grating 7 or an increase in light leakage is prevented. Consequently, by the quantum cascade laser element 1, a single-mode light can be reliably CW-oscillated even at room temperature or a temperature in proximity thereof.

Abstract: In a quantum cascade laser device 1, a laminate structure 11 is formed into a stripe shape along a predetermined direction on a principal surface at one side of a substrate 10, and insulating layers 15 are formed on bilateral sides of the laminate structure 11, and an insulating layer 16 and a metal layer 17 are formed in sequence on the laminate structure 11 and the insulating layers 15. The laminate structure 11 is formed such that a cladding layer 12, an active layer 13, and a cladding layer 14 are formed in sequence from the side of the substrate 10. In the active layer 13, light emitting layers and injection layers are alternately laminated, and the active layer 13 generates light due to intersubband electron transition in a quantum well structure. A shape in a cross section of the laminate structure 11 perpendicular to the direction in which the laminate structure 11 is provided to extend is formed into a rectangle or an inverted mesa shape.