A laser system including: A. a laser apparatus configured to output a pulse laser beam; B. an optical pulse stretcher including a delay optical path for expanding a pulse width of the pulse laser beam; and C. a phase optical element included in the delay optical path and having a function of spatially and randomly shifting a phase of the pulse laser beam. The phase optical element includes a plurality of types of cells providing different amounts of phase shift to the pulse laser beam and arranged irregularly in any direction.

Disclosed is a system for generating wavelength-tunable, ultra-short light pulses within the visible or infrared light spectrum. The system includes an injection module including a light source and a wavelength-tunable spectral filter. The light source is suitable for generating short light pulses, having a duration measured in nanoseconds, within an emission spectrum having a spectral width of several tens of nanometers to several hundred nanometers. The spectral filter has a spectral width between 250 pm and 3 nm and is suitable for spectrally and temporally filtering the short light pulses such that the injection module generates wavelength-tunable, spectrally filtered, ultra-short light pulses. The system also includes at least one optical amplifier suitable for generating wavelength-tunable, ultra-short, amplified pulses based on the wavelength of the spectral filter.

In one aspect, the present disclosure describes a fiber laser system for the generation and delivery of femtosecond (fs) pulses in multiple wavelength ranges. For improved versatility in multi-photon microscopy, an example of a dual wavelength fiber system based on Nd fiber source providing gain at 920 and 1060 nm is described. An example of a three-wavelength system is included providing outputs at 780 nm, 940 nm, and 1050 nm. The systems include dispersion compensation so that high quality fs pulses are provided for applications in microscopy, for example in multiphoton microscope (MPM) systems.

An optical pulse generator arranged to generate an initial sequence of optical pulses having an initial inter-pulse period; and an optical pulse burst formation apparatus including: an interleaving stage to receive an initial sequence of optical pulses having an initial inter-pulse period, including: an optical splitter to power split received optical pulses, thereby generating a first and second replica sequences of optical pulses; a first optical arm to receive the first replica sequence, having a first optical path length; and a second optical arm to receive the second replica sequence, having a second optical path length, different to the first optical path length by a path length difference; and an optical combiner arranged to combine the first replica sequence of pulses and the second replica sequence of delayed pulses to form an output sequence of optical pulse bursts.

A laser system for nonlinear pulse compression includes a laser source configured to generate laser pulses with a pulse energy of at least 50 mJ, a spectral broadening device for spectrally broadening the high-energy laser pulses using self-phase modulation, and a compression device including a grating compressor having at least two diffraction gratings and configured to compress the spectrally broadened high-energy laser pulses. The laser system is configured to generate a pulse duration of the high-energy laser pulses of less than 100 fs.

A laser apparatus including an optical element made of a CaF.sub.2 crystal and configured to transmit an ultraviolet laser beam obliquely incident on one surface of the optical element, the electric field axis of the P-polarized component of the laser beam propagating through the optical element coinciding with one axis contained in <111> of the CaF.sub.2 crystal, with the P-polarized component defined with respect to the one surface. A method for manufacturing an optical element, the method including causing a seed CaF.sub.2 crystal to undergo crystal growth along one axis contained in <111> to form an ingot, setting a cutting axis to be an axis inclining by an angle within 14.18±5° with respect to the crystal growth direction toward the direction of another axis contained in <111>, which differs from the crystal growth direction, and cutting the ingot along a plane perpendicular to the cutting axis.

Disclosed is a system and method for remote sensing, surface profiling, object identification, and aiming based on two-photon population inversion and subsequent photon backscattering enhanced by superradiance using two co-propagating pump waves. The present disclosure enables efficient and highly-directional photon backscattering by generating the pump waves in properly pulsed time-frequency modes, proper spatial modes, with proper group-velocity difference in air. The pump waves are relatively delayed in a tunable pulse delay device and launched to free space along a desirable direction using a laser-pointing device. When the pump waves overlap in air, signal photons will be created through two-photon driven superradiant backscattering if target gas molecules are present. The backscattered signal photons propagate back, picked using optical filters, and detected. By scanning the relative delay and the launching direction while the signal photons are detected, three-dimensional information of target objects is acquired remotely.

Generator for wholly optical tunable broadband linearly chirped signal comprising a mode-locked laser, a first optical coupler, a first optical filter, a first dispersion module, a second optical filter, a second dispersion module, a tunable time delay module, a second optical coupler, an optical amplifier, and a photodetector. The generator of the present invention employs just one mode-locked laser as a light source, thus preventing instability of the generated signal resulting from independent unrelated lasers. By making use of the principle of wavelength-time mapping and by means of adjusting the center wavelength and the filter bandwidth of the first optical filter and the second optical filter, easy and flexible tuning of the center frequency and sweep bandwidth of the generated linearly chirped signal is realized. The present invention possesses a big advantage on the aspect of generating a broadband linearly chirped signal over other solutions.

A method for generating femtosecond vortex beams with high spatial intensity contrast, where a noncollinearly pumped HG beam femtosecond laser generates femtosecond HG beam and a cylindrical lens mode converter converts the femtosecond HG beam to femtosecond LG vortex beam. The HG beam femtosecond laser comprises a pump source, a gain medium, a saturable absorption mirror as mode-locker, and an output coupler with a noncollinear angle between the laser beam and the pump beam in the gain medium, which enables the laser to generate pure, order-tunable femtosecond HG beams. Femtosecond vortex beams obtained after the cylindrical lens converter have high-intensity-contrast, and are topological charge-tunable.

The invention relates to a device comprising: a laser source emitting a first beam with a central wavelength λ.sub.1 lying between 1010 nm and 1050 nm, a spectral supercontinuum generator downstream of the laser source, generating a second beam with a central wavelength λ.sub.2 lying between 1670 nm and 1730 nm from a part of the first beam, an optical parametric amplification system downstream of the spectral supercontinuum generator, generating a third beam with a central wavelength λ.sub.3 lying between 2540 nm and 2690 nm from at least a part of the second beam and a part of the first beam, and a second harmonic generator downstream of the optical parametric amplification system, the second harmonic generator generating a fourth beam with a central wavelength λ.sub.4 lying between 1270 nm and 1345 nm from at least a part of the third beam.