A multi-stage optical amplifier has an input port for receiving an optical signal and a relatively short erbium doped optical fiber is coupled to the input port. Complex costly pump feedback is not required as a constant non-varying saturation pump is configured to provide non varying output power pump light of a predetermined wavelength suitable for excitation and full saturation of the erbium ions such that a full population inversion occurs. The length of the short erbium doped fiber and rare earth doping concentration of the erbium doped fiber is such that when pumped by said pump provides amplification of the optical signal of less than 15 dB. Locating a gain flattening filter after the short erbium doped optical fiber provides a relatively flat amplified output signal. Multi-stages of similar short erbium doped fibers pumped and saturated by the same pump signal economically provide increased amplification of the signal and filters after each state flatten the gain.

A high-efficiency non-collinearly phase matched parametric oscillator is provided, wherein a laser pumps a nonlinear optical material with a plural number of flat reflection surfaces that zigzag at least one parametrically generated off-axis radiation about the pump laser beam axis via multiple reflections from the surfaces. The off-axis zigzag oscillation of the radiation establishes parametric oscillation and improves energy coupling among mixing waves in a monolithic nonlinear optical material. Preferably the pump laser has a transverse beam size covering the area of the zigzagging parametrically generated radiation. To further enhance the performance of the off-axis zigzag parametric oscillator, the other parametrically generated radiation can be seeded by an external laser source or resonated in a cavity. The present invention also includes a double-side pumped off-axis zigzag parametric oscillator installed inside a standing-wave pump-laser cavity.

The invention relates to a discoidal or cuboidal solid body for a laser amplification system of a solid-state laser, which solid body contains at least one laser-active material, has an upper side defining an upper side plane and a lower side defining a lower side plane, wherein the upper side plane and the lower side plane are inclined in relation to each other and enclose an angle of inclination, wherein the lower side is provided with a first reflective coating, wherein the upper side is provided with a second reflective coating, and wherein at least one of the upper side and the lower side has at least one optical input coupling opening for input coupling at least one of a seed laser radiation field and a pump laser radiation field into the solid body between the first and the second reflective coating.

A laser amplifier includes a broadband laser gain medium having a first lateral face spaced from an opposing second lateral face at a wedge angle with respect to the first lateral face. At least the first lateral face receives a pump beam and one of the first and second lateral faces receives a seed beam. A first coating on the first lateral face is highly transmissive at the pump beam wavelength. A second coating is disposed on the second lateral face. In one example, the first coating is highly reflective at the seed beam wavelength over a first wavelength band and the second coating is highly reflective at the seed beam wavelength over a second wavelength band (partially or fully) overlapping the first wavelength band.

There is provided a laser system having a cylindrically-shaped annular minor with at least one opening in its surface; a pair of planar metallic electrodes disposed proximate opposite edges of the annular mirror, normal to the axis of the annular minor, the electrodes configured to have an RF field applied between them; a pair of end minors disposed at said at least one opening; and a ceramic material in the form of a disc, disposed in the internal volume of the annular minor, the ceramic material having a series of channels formed therein such that they generate a zig-zag pathway in the ceramic material, wherein (i) the zig-zag path, when filled with a gain medium, (ii) the annular minor and (iii) the pair of end minors, together constitute a laser cavity.

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.

The invention includes a device for amplifying light having a pumping resonator and a Raman resonator that share an output mirror and are divided by an interior mirror. A pumping beam is directed though a gain medium in each resonator. A seed signal is directed into the Raman resonator, which is configured to contain cascaded Raman-shifted signals generated through the interaction of the pumping beam, seed signal, and gain medium, and to transmit a selected Raman-shifted signal as optical output. Also disclosed is a method of amplifying light using a Raman resonator that partially overlaps a pump resonator. A pumping beam is directed through a pump gain medium and a Raman gain medium and generates cascading Raman-shifted signals within the Raman resonator. A seed signal is used to shape the temporal profile, and improve the coherence, of the Raman-shifted signals.

A laser system includes a laser radiation source for providing pulsed laser radiation, and an optical system that includes a first polarization setting optical unit configured to set a circular polarization state of the pulsed laser radiation and a multipass cell having at least two mirrors. The pulsed laser radiation passes through the multipass cell with formation of a plurality of intermediate focus zones. The multipass cell is filled with a filling gas that has an optical nonlinearity and causes a spectral broadening of the pulsed laser radiation in the intermediate focus zones. A pressure of the filling gas is set in a pressure range so that there is an ionization behavior of the filling gas in a form of multiphoton ionization. Focus diameters of the intermediate focus zones are set such that the pulsed laser radiation passes through the multipass cell without ionization of the filling gas.

A laser amplifier includes a planar optical waveguide for laser amplification, and an input optical system for inputting signal light to a core layer of the planar optical waveguide. The input optical system includes: a collimating lens for converting output light from a signal light source into parallel light; an anamorphic prism for reducing the beam width in a first direction of output light from the collimating lens; and a cylindrical lens for collecting output light from the anamorphic prism in a second direction, and output light from the cylindrical lens is input to the core layer.

A compact laser system with a folded annular resonator cavity defined by spherical mirrors (17, 18), enabling the generation of a multipass beam path between the mirrors, each beam pass inclined at a small angle to the axis between the mirrors to form a zig-zag path (28, 29) therebetween. A long optical path is achieved within a short physical structure. The optical resonator cavity is confined in the gap between two cylindrical coaxial electrodes (13, 14) receiving RF power to excite the lasing gas. Apertures (23) are provided in the main cavity mirrors (17, 18), with a high reflectivity end mirror (24) behind one aperture at one end and a partially reflective output coupler (25) at the other end. A channeled ceramic cylindrical element (15, 20) within the annular shaped gap between the two cylindrical electrodes confines the lasing gas to the channels (16).