The present invention provides a laser, including: a medium, having a ground state, an intermediate state, and an excited state in ascending order of energy; an excitation system, configured to excite electrons in the medium from the ground state to the intermediate state; and an excitation laser, configured to drive electrons in the intermediate state at different spatial positions in the medium to the ground state through a stimulated emission process with a fixed phase relationship, to generate a laser with a shorter relative wavelength. Due to the use of an excitation laser to drive electrons from the intermediate state, the photons generated by the stimulated emission have coherence, thereby forming a laser. In the present invention, an excitation system performing primary pumping combined with an excitation laser with a relatively long wavelength performing secondary pumping generate lasers with a relatively short wavelength, and the structure of the short-wavelength laser is simple, compact, and easy to be implemented. In addition, the cost of the short-wavelength laser can be reduced, and a laser with a shorter wavelength can be obtained.

An apparatus includes at least one Raman medium configured to receive a pump beam and shift at least a portion of the pump beam into a Stokes-shifted output beam. The apparatus also includes a first lens configured to receive and focus the pump beam into the at least one Raman medium. The apparatus further includes first and second retro-lens assemblies, each including at least one prism configured to reflect beams from the at least one Raman medium back into the at least one Raman medium and multiple second lenses configured to control optical propagation of the beams entering and exiting the at least one Raman medium. Multiple pairs of lenses form multiple confocal arrangements of lenses. The pairs of lenses include the first lens and the second lenses of the retro-lens assemblies. The at least one Raman medium is optically positioned between the lenses in the confocal arrangements of lenses.

A low wavelength infrared Super Continuum (SC) signal from a master oscillator introduces two or more seeds into an amplifier that supports the Raman effect. A counter-propagating, high-power, continuous wave, or quasi-continuous wave quantum cascade lasers pump (amplifies) a first optical seed creating a cascading amplification of subsequent optical seeds forming two or more tunable wavelength coherent optical pump sources.

A system includes a signal seeder configured to generate a pulsed seed signal, where the signal seeder includes a master oscillator configured to generate an optical signal at a first wavelength. The system also includes a series of optical preamplifiers collectively configured to amplify the pulsed seed signal and generate an amplified signal. The system further includes a Raman fiber amplifier configured to amplify the amplified signal and generate a Raman-shifted amplified signal. The Raman fiber amplifier is configured to shift a wavelength of the amplified signal to a second wavelength different than the first wavelength during generation of the Raman-shifted amplified signal.

A gas laser device includes a shielding plate that is a first shielding member, and a shielding plate that is a second shielding member. The first shielding member includes a first opening, and a second opening. A laser beam that is to be propagated to discharge regions passes through the first opening. The laser beam that has taken a round trip through the discharge regions after passing through the first opening passes through the second opening. The second shielding plate faces the first shielding member the discharge regions located therebetween. The shielding plate includes an opening that is a third opening. The laser beam that has been propagated through the first opening and the discharge regions, and the laser beam that is to be propagated to the second opening through the discharge regions pass through the third opening. A plane shape of the third opening includes a rectilinear segment.

Techniques are provided for scaling the average power of high-energy solid-state lasers to high values of average output power while maintaining high efficiency. An exemplary technique combines a gas-cooled-slab amplifier architecture with a pattern of amplifier pumping and extraction in which pumping is continuous and in which only a small fraction of the energy stored in the amplifier is extracted on any one pulse. Efficient operation is achieved by propagating many pulses through the amplifier during each period equal to the fluorescence decay time of the gain medium, so that the preponderance of the energy cycled through the upper laser level decays through extraction by the amplified pulses rather than through fluorescence decay.

An optical amplifier includes two amplifier stages, a circulator and an output stage. The first amplifier stage amplifies an input optical signal, and provides a first-stage amplified optical signal that is to be outputted via the circulator to the second amplifier stage. The second amplifier stage amplifies the first-stage amplified optical signal, and outputs a second-stage amplified optical signal to the output stage. The output stage outputs a returned optical signal to the second amplifier stage, so that the second amplifier stage amplifies the returned optical signal, and provides a third-stage amplified optical signal that is to be outputted via the circulator and the output stage to serve as an output optical signal.

A wavelength converter including: A. a crystal holder configured to hold a nonlinear crystal configured to convert a wavelength of a laser beam incident thereon and output the wavelength-converted laser beam; B. a first container configured to accommodate the crystal holder and include a light incident window so provided as to intersect an optical path of the laser beam incident on the nonlinear crystal and a light exiting window so provided as to intersect the optical path of the laser beam having exited out of the nonlinear crystal; C. a second container configured to accommodate the first container; D. a position adjusting mechanism configured to adjust at least a position of the first container; and E. an isolation mechanism configured to spatially isolate the light incident window and the light exiting window from the position adjusting mechanism.

A device includes a laser source, an amplifier, an optical sensor and a spectrometer. The laser source is configured to produce a seed laser beam. The amplifier includes gain medium and a discharging unit. The discharging unit is configured to pump the gain medium for amplifying power of the seed laser beam. The optical sensor is coupled to the amplifier and configured for sensing an optical emission generated in the amplifier while the gain medium is discharging. The spectrometer is coupled with the optical sensor and configured to measure a spectrum of the optical emission.

A laser device for optical communication comprises a first laser unit connected to a first optical fiber for supplying a transmission laser beam thereto. wherein the laser device is configured for providing a reference laser beam in addition to the transmission laser beam. For providing the reference laser beam the laser device further includes a second laser unit connected to a second optical fiber for supplying the reference laser beam to the second optical fiber. The first laser unit is configured for providing the transmission laser beam as a linear polarized beam that is polarized in a first polarization direction, and the second laser unit is configured for providing the reference laser beam as a linear polarized beam that is polarized in a second polarization direction. The first optical fiber and the second optical fiber are formed of polarization maintaining optical fibers, and the laser device further includes a polarization combiner connected to a third polarization maintaining optical fiber for conveying the transmission laser beam and the reference laser beam to an optical output of the laser device.