A fiber laser includes: a gain fiber; a first low-reflective mirror and a second high-reflective mirror disposed in an optical path of laser light that is emitted from a first end of the gain fiber; a second low-reflective mirror and a first high-reflective mirror disposed in an optical path of laser light that is emitted from a second end of the gain fiber; a first delivery fiber that accepts the laser light emitted from the first end; a second delivery fiber that accepts the laser light emitted from the second end; and an operation mode switching mechanism that switches between a first operation mode and a second operation mode. A first resonator is constituted by the first low-reflective mirror and the first high-reflective mirror. A second resonator, which is constituted by the second low-reflective mirror and the second high-reflective mirror.

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.

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.

A combination of microvalves and waveguides may enable the creation of reconfigurable on-chip light sources compatible with planar sample preparation and particle sensing architecture using either single-mode or multi-mode interference (MMI) waveguides. A first type of light source is a DFB laser source with lateral gratings created by the light valves. Moreover, feedback for creating a narrowband light source does not have to be a DFB grating in the active region. A DBR configuration (Bragg mirrors on one or both ends of the active region) or simple mirrors at the end of the cavity can also be used. Alternately, ring resonators may be created using a valve coupled to a bus waveguide where the active gain medium is either incorporated in the ring or inside an enclosed fluid. The active light source may be activated by moving a fluid trap and/or a solid-core optical component defining its active region.

An excimer laser apparatus according to the present disclosure includes a chamber configured to accommodate a laser gas and a pair of electrodes and generate pulse-oscillating laser light when the gas pressure of the laser gas is controlled in accordance with voltage applied between the pair of electrodes, a power supply configured to apply the voltage between the pair of electrodes, and a controller to which a target value of the spectral linewidth of the laser light is inputted, the controller configured to correct the voltage used to control the gas pressure, when the target value changes from a first target value to a second target value, based on a first function having the second target value as a parameter and control the gas pressure in accordance with the corrected voltage.

A fiber laser producing a beam of ultrashort laser pulses at a repetition rate greater than 200 MHz includes a linear fiber resonator and a fiber branch. Ultrashort laser pulses are generated by passive mode-locking and circulate within the linear fiber resonator. Each circulating laser pulse is split into a portion that continues propagating in the linear fiber resonator and a complementary portion that propagates through the fiber branch and is then returned to the linear fiber resonator. The optical length of the linear fiber resonator is an integer multiple of the optical length of the fiber branch. The repetition rate of the ultrashort laser pulses is the reciprocal of the propagation time of the laser pulses through the fiber branch.

A fiber laser producing a beam of ultrashort laser pulses at a repetition rate greater than 200 MHz includes a linear fiber resonator and a fiber branch. Ultrashort laser pulses are generated by passive mode-locking and circulate within the linear fiber resonator. Each circulating laser pulse is split into a portion that continues propagating in the linear fiber resonator and a complementary portion that propagates through the fiber branch and is then returned to the linear fiber resonator. The optical length of the linear fiber resonator is an integer multiple of the optical length of the fiber branch. The repetition rate of the ultrashort laser pulses is the reciprocal of the propagation time of the laser pulses through the fiber branch.

An external resonator-type semiconductor laser device 1A includes an external resonator formed of one or a plurality of laser diode light sources and a VBG; an optical fiber which outputs output light La from the laser diode light source toward the VBG, and into which return light Lb from the VBG is input; and a displacement unit that displaces a disposition position of the VBG with respect to an input and output end surface of the optical fiber.

A system and method for tuning and infrared source laser in the Mid-IR wavelength range. The system and method comprising, at least, a plurality of individually tunable emitters, each emitter emitting a beam having a unique wavelength, a grating, a mirror positioned after the grating to receive at least one refracted order of light of at least one beam and to redirect the beam back towards the grating, and a micro-electro-mechanical systems device containing a plurality of adjustable micro-mirrors.

Online calibration of laser performance as a function of the repetition rate at which the laser is operated is disclosed. The calibration can be periodic and carried out during a scheduled during a non-exposure period. Various criteria can be used to automatically select the repetition rates that result in reliable in-spec performance. The reliable values of repetition rates are then made available to the scanner as allowed values and the laser/scanner system is then permitted to use those allowed repetition rates.