A glass processing method according to a viewpoint of the present disclosure includes generating a pulse laser beam by using a laser oscillator, and irradiating alkali-free glass to be processed with the pulse laser beam. The wavelength of the pulse laser beam ranges from 248 nm to 266 nm, and the pulse laser beam has an energy ratio greater than or equal to 91% but smaller than or equal to 99% in the region from 5 ns after a pulse rises to 400 ns.

A mode-lockable ring oscillator includes a gain element for amplifying an optical pulse into an amplified pulse, a nonlinear optical element for broadening the amplified pulse into a first spectrally-broadened pulse, a first optical filter for filtering the first spectrally-broadened pulse into a first filtered pulse, a passive nonlinear optical element for broadening the first filtered pulse into a second spectrally-broadened pulse, and a second optical filter for filtering the second spectrally-broadened pulse into a second filtered pulse. The first and second optical filters have passbands that partially overlap such that the ring cavity can lase CW. With these spectrally overlapping passbands, the mode-lockable ring oscillator can directly initiate single-pulse mode-locking by modulating pump power that pumps the gain element. After this modulation has stopped, the mode-lockable ring oscillator maintains this single-pulse mode-locking while the passbands remain spectrally overlapped.

A system configuration that significantly improves the laser damage threshold of multi-layer dielectric gratings for lasers applications includes three main sections: 1) a laser module, 2) a TM polarization module, and 3) a multi-layer dielectric grating optimized for high efficiency operation with transverse magnetic polarized laser light.

An optical apparatus for spectrally shaping a laser beam within a fiber MOPA laser is disclosed. The apparatus includes a birefringent optic and a linear polarizer. The laser beam is divided between two orthogonal polarization axes of the birefringent optic having polarization mode dispersion. Propagation of the laser beam through the birefringent optic causes a wavelength-dependent phase shift between components of the laser beam in the two polarization axes. A polarizing direction of the polarizer is oriented between the two polarization axes. Propagation of the polarization-dispersed laser beam through the polarizer modulates the power spectral density of a transmitted portion of the laser beam. This spectral modulation can be tuned to shape a Gaussian spectral distribution from the master oscillator into a uniform spectral distribution for amplification by the power amplifier. The uniform spectrally-shaped laser beam can be amplified to higher powers than the original Gaussian laser beam.

A delay mirror 1 includes a base 2, and an optical multilayer film 4 formed on a surface R of the base 2. The value of a group delay in a first wavelength band according to the optical multilayer film 4 is different from the value of the group delay in the second wavelength band according to the optical multilayer film 4, and the value of a group delay dispersion in the first wavelength band according to the optical multilayer film 4 and the value of the group delay dispersion in the second wavelength band according to the optical multilayer film 4 are each not less than −100 fs.sup.2 and not greater than 100 fs.sup.2. Further, the delay mirror system includes a delay mirror movement mechanism which moves the delay mirror 1 such that the number of times of reflection is changed.

A system for determining an absolute carrier-envelope phase (CEP) of ultrashort laser pulses includes a laser system for generating a laser beam including ultrashort optical pulses of a duration of less than 10 fs, an ultrabroadband quarter-wave plate configured to polarize the laser beam, and a gas jet emitting a continuous jet stream into the laser beam. The system includes focusing optics to adjust a focal spot of the laser beam to the gas jet, and a detector arrangement including a beam block and a microchannel plate (MCP) imaging detector, wherein the laser beam is directed to the detector arrangement. The method involves using angular streaking to determine the absolute CEP of both elliptically and linearly polarized light.

The method comprises A method includes steps for creating at least two replicas of an input pulse to be characterised, varying the relative amplitude of the two replicas within a range, creating a nonlinear signal at each case of said amplitude variation, measuring the spectra of the nonlinear signals and recovering the spectral amplitude and phase of the input pulse with a proper algorithm. The system includes a replicator for creating at least two replicas of the input pulse and varying their relative amplitude within a range of relative amplitudes, a nonlinear medium, which obtains a nonlinear signal for each relative amplitude, and an analyzer, associated to the nonlinear signal for measuring and characterising spectrally each nonlinear signal.

An optical system for increasing contrast of pulsed laser radiation includes a first polarization setting optical unit for setting an elliptical polarization state of the pulsed laser radiation, and a multipass cell having at least two opposing mirrors. The pulsed laser radiation passes the multipass cell with formation of a plurality of intermediate focus zones. The multipass cell is filled with a gas having an optical nonlinearity that causes an intensity-dependent rotation of an alignment of the elliptical polarization state of the pulsed laser radiation, such that the multipass cell outputs beam portions having differently aligned elliptical polarization states on account of the intensity-dependent rotation. The optical system further includes an optical beam splitting system for splitting the beam portions having differently aligned elliptical polarization states.

Provided is a two-photon spectroscopy including a light source configured to generate first laser light having a pulse, a pulse width correction device configured to receive the first laser light to output a second laser light, an optical system through which the second laser light passes, a first two-photon sensor configured to measure a first pulse width of the first laser light generated from the light source, and a second two-photon sensor configured to measure a second pulse width of the second laser light passing through the optical system, wherein the pulse width correction device corrects a difference between the first pulse width and the second pulse width.

An extended optical pulse stretcher is provided that combines confocal pulse stretchers in combination to produce, for example, 4 reflections, 4 reflections, 12 reflections, and 12 reflections per optical circuit configuration. The inclusion of the combination of different mirror separations and delay path lengths can result in very long pulse stretching, long optical delays, and minimal efficiency losses. Also, in the extended optical pulse stretcher, at least a beam splitter can be positioned relative to the center of curvature of the mirrors to “flatten” each of the circuits to enable the beam to propagate in the same plane (e.g., parallel to the floor). Also, the curvatures and sizes of the individual mirrors can be designed to position the beam splitter closer to one of the banks of mirrors to allow the optical pulse stretchers to properly fit in an allocated location in a laser system.