A waveguide gas laser having a laser resonator cavity of a variable length is subjected to cyclical varying of the length of the cavity during generation of a laser beam a length variation amount sufficient to force a laser beam generated in the resonator cavity though a substantially complete optical longitudinal cavity mode at a rate operable to smooth at least one laser beam parameter variation. In this manner variation in the laser beam parameter is averaged by moving through at least a portion of an optical longitudinal cavity mode.

An apparatus may include a diode-pumped solid-state laser oscillator configured to output a pulsed laser beam, a modulator configured to modify an energy and a temporal profile of the pulsed laser beam, and an amplifier configured to amplify an energy of the pulse laser beam. A modified and amplified beam to laser peen a target part may have an energy of about 5J to about 10 J, an average power (defined as energy (J)frequency (Hz)) of from about 25 W to about 200 W, with a flattop beam uniformity of less than about 0.2. The diode-pumped solid-state oscillator may be configured to output a beam having both a single longitudinal mode and a single transverse mode, and to produce and output beams at a frequency of about 20 Hz.

An apparatus may include a diode-pumped solid-state laser oscillator configured to output a pulsed laser beam, a modulator configured to modify an energy and a temporal profile of the pulsed laser beam, and an amplifier configured to amplify an energy of the pulse laser beam. A modified and amplified beam to laser peen a target part may have an energy of about 5J to about 10 J, an average power (defined as energy (J)frequency (Hz)) of from about 25 W to about 200 W, with a flattop beam uniformity of less than about 0.2. The diode-pumped solid-state oscillator may be configured to output a beam having both a single longitudinal mode and a single transverse mode, and to produce and output beams at a frequency of about 20 Hz.

A single longitudinal mode ring Raman laser including: a pump source outputting a pump light power, resonantly coupled to a first ring resonator; a optical measurement and piezo-actuator for stabilising the resonant coupling of the pump light power to a first ring resonator; a first ring resonator including a Raman gain medium, wherein the Raman gain medium receives the pump light power and undergoes Raman lasing generating resonated Stokes power at the corresponding Stokes output wavelength; the first ring resonator acting as a feedback loop for the pump light power and the resonated Stokes power and outputting a portion of the Stokes power as the laser output.

A line narrowing module includes a prism that refracts laser light in a first plane, a grating that disperses the laser light in the first plane, first to fourth elements, and a rotation mechanism and narrows the linewidth of the laser light. The second element is supported between the first and fourth elements by the first element. The rotation mechanism rotates the second element relative to the first element around an axis intersecting the first plane. The prism is located between the second and fourth elements and so supported by the second element that the rotation mechanism rotates the prism and the second element. The third element has elasticity and is compressed and located between the prism and the fourth element. The fourth element receives reaction force from the compressed third element. The second element is mechanically independent of the fourth element in the rotational direction of the rotation mechanism.

A laser light source is provided including an airtight container. A first resonance mirror and a second resonance mirror are disposed outside the airtight container. The first resonance mirror includes a lens unit and a reflection coating layer. The lens unit includes a first surface and a second surface, and the first surface is inclined with respect to the second surface.

A method and system for injection-locking multiple optical amplifiers is disclosed. A master laser is employed to generate a continuous-wave output field. Optical modulators then produce first and second seed optical fields from the continuous-wave output field. The first and second seed optical fields provide an input to injection lock one or more optical amplifiers, optionally at different operating frequencies. Since the first and second seed optical fields are generated from the continuous-wave output field then the output fields of the optical amplifiers exhibit a high phase-coherence with each other and with the continuous-wave output field. Employing the first and second optical fields reduces the requirement to induce large frequency shifts on a single optical field. Techniques for phase-locking the output of the injection-locked laser systems are also provided to further reduce phase noise within the systems.

A tunable laser includes a housing having a sealable accommodating cavity, an optical interface and an electrical interface disposed on the housing, a tunable semiconductor laser apparatus, a splitter component, and a photodetector. The tunable semiconductor laser apparatus is disposed in the accommodating cavity for emitting an optical signal whose wavelength is tunable. An electrical signal inputted through the electrical interface controls the tunable semiconductor laser apparatus to emit the optical signal. The optical signal is outputted through the optical interface. The splitter component and the photodetector are disposed outside the housing. The optical signal is split into at least two beams of light by the splitter component after the optical signal is outputted through the optical interface. The photodetector is configured to receive one of the beams of light to monitor the optical signal emitted by the tunable semiconductor laser apparatus.

The invention relates to a method for maintaining the synchronism of a Fourier Domain Mode Locked (FDML) laser, the FDML laser comprising at least one dispersion-compensated resonator with at least one variably wavelength-selective optical filter, the laser light circulating in the resonator at a circulation frequency, and the wavelength selectivity of the filter being repeatedly modified at a syntonising rate, the FDML laser being synchronous when the syntonising rate is an integral multiple of the circulation frequency. Said method is characterised by the following steps: a) at least a portion of the laser light is coupled out of the resonator; b) at least a portion of the decoupled laser light is detected by means of a photodetector; c) amplitudes in the measuring signal of the photodetector are counted during successive counting intervals; and d) the circulation frequency or syntonising rate is adjusted such that the ratios of the count value to the lengths of the counting intervals are maintained within a predetermined nominal value interval.

A wavelength sensor for wavelength stabilization of a laser beam includes an etalon placed in the laser beam and tilted with respect to the laser beam. Reflected beams from the etalon form an interference pattern on a segmented photodetector having two detector segments. Output signals from the two detector segments are used to derive an error signal for a closed control loop to effect the wavelength stabilization.