A Q switch is vibrated by applying a first voltage, and pulsed laser light is emitted by applying a second voltage to the Q switch at a point in time at which a preset delay time has passed from the start of emission of excitation light. Then, in this case, a time which is within a period, for which the vibration of the Q switch continues, and at which the intensity of the pulsed laser light periodically changing due to the vibration of the Q switch is maximized in a case where a point in time of application of the second voltage to the Q switch is changed is set as the delay time.

Apparatuses and methods are disclosed for applying laser energy having desired pulse characteristics, including a sufficiently short duration and/or a sufficiently high energy for the photomechanical treatment of skin pigmentations and pigmented lesions, both naturally-occurring (e.g., birthmarks), as well as artificial (e.g., tattoos). The laser energy may be generated with an apparatus having a resonator with the capability of switching between a modelocked pulse operating mode and an amplification operating mode. The operating modes are carried out through the application of a time-dependent bias voltage, having waveforms as described herein, to an electro-optical device positioned along the optical axis of the resonator.

A system and method for stabilizing and combining multiple emitted beams into a single system using both WBC and WDM techniques.

A multipass laser amplifier includes a mirror, a mirror device, a gain crystal, and refractive or diffractive beam-steering element. The gain crystal is positioned on a longitudinal axis of the multipass laser amplifier between the mirror and the mirror device. The beam-steering element is positioned on the longitudinal axis between the gain crystal and the mirror device. The beam-steering element has no optical power and deflects a laser beam, by refraction or diffraction, for each of multiple passes of the laser beam between the first mirror and the mirror device, such that each pass goes through the gain crystal for amplification of the laser beam and goes through a different respective off-axis portion of the beam-steering element. The no optical power of the beam-steering element enables maintaining a large beam size in the gain crystal, thereby facilitating amplification to high average power.

A WDM seed beam source for a fiber laser amplifier system that includes a number of master oscillators that generate seed beams at different wavelengths and a spectral multiplexer that multiplexes all of the seed beams onto a single fiber. An EOM modulates the combined seed beams on the single fiber and a spectral demultiplexer then separates the modulated seed beams into their constituent wavelengths on separate fibers before the seed beams are amplified and spectrally combined. The fiber laser amplifier system includes a separate fiber amplifier that amplifies the separated seed beams, an emitter array that directs the amplified beams into free space, beam collimating optics that focuses the uncombined beams, and an SBC grating responsive to the collimated uncombined beams that spatially combines the collimated uncombined beams.

A method generates laser pulses by varying a Q-factor in a resonator. The method includes generating the laser pulses by controlling an optical modulator with a control signal for switching over between a first operating state of the optical modulator for generating a first Q-factor in the resonator and a second operating state of the optical modulator for generating a second Q-factor in the resonator. The second Q-factor is different than the first Q-factor. In order to generate a sequence of the laser pulses in which first laser pulses alternate with second laser pulses different than the first laser pulses, the optical modulator is controlled differently in each case alternately with the control signal for generating a respective first laser pulse, of the first laser pulses, and a respective second laser pulse, of the second laser pulses.

Apparatuses and methods are disclosed for applying laser energy having desired pulse characteristics, including a sufficiently short duration and/or a sufficiently high energy for the photomechanical treatment of skin pigmentations and pigmented lesions, both naturally-occurring (e.g., birthmarks), as well as artificial (e.g., tattoos). The laser energy may be generated with an apparatus having a resonator with the capability of switching between a modelocked pulse operating mode and an amplification operating mode. The operating modes are carried out through the application of a time-dependent bias voltage, having waveforms as described herein, to an electro-optical device positioned along the optical axis of the resonator.

There is provided a passive Q-switch pulse laser device including a laser medium, and a saturable absorber. The laser medium is disposed between a pair of reflection means included in an optical resonator. The laser medium is excited by specific excitation light to emit emission light. The saturable absorber is disposed on an optical axis of the optical resonator and on a downstream side of the laser medium between the pair of reflection means. The saturable absorber has a transmittance increased by absorption of the emission light. At least one of the pair of reflection means is a polarizing element. The polarizing element has different reflectances with respect to the respective pieces of emission light in polarization directions orthogonal to each other.

Self-isolated lasers are provided by using a chiral metasurface in combination with a spin-selective gain medium and symmetry-breaking (i.e., not linearly polarized) optical pumping. In preferred embodiments the chiral metasurface is resonant, thereby proving an integrated optical resonator to support lasing. The chiral metasurface can be the spin-selective gain medium, or it can be formed on a surface of the spin-selective gain medium, or it can be distinct from the spin-selective gain medium.

A tunable narrow-linewidth photo-generated microwave source based on polarization control includes a high-reflectivity fiber grating, a high-gain fiber, a low-reflectivity polarization-maintaining fiber grating, a stress adjusting device, a single-mode semiconductor pump laser, an optical wavelength division multiplexer, a polarization beam splitter, a polarization controller, an optical coupler, and a photoelectric detector. Birefringence distribution in the low-reflectivity polarization-maintaining fiber grating is controlled by adjusting a stress magnitude of the stress adjusting device to the low-reflectivity polarization fiber grating, thereby controlling a laser frequency working in different polarization modes in a resonant cavity, and a tunable narrow-linewidth photo-generated microwave source is generated by a beat-frequency technology using a dual-wavelength narrow-linewidth laser with variable frequency intervals.