Abstract: A high-gain optical amplifier for a wave to be amplified at a wavelength referred to as the emission wavelength, includes: optical pumping elements (4) producing a pump wave at a wavelength referred to as the pump wavelength; a solid amplifying medium (1) that is doped with active ions, the solid amplifying medium being capable of emitting laser radiation at the emission wavelength when the medium is pumped by the pumping elements; cooling elements (2) capable of cooling the solid amplifying medium to a temperature of no higher than 250 Kelvin; and optical multiplexing elements capable of coupling together the pump wave and the wave to be amplified in the amplifying medium. The amplifying medium has Stark sublevels contained within a spectral domain ranging over less than 200 cm?1 (approximately 20 nm, when expressed in wavelength). A laser including a resonant optical cavity and an amplifier are also described.

Abstract: Method for shielding a high-power laser apparatus (S) in which a laser beam is generated and then amplified in at least a first amplification stage, including spatial filtering (4) of the amplified laser beam, phase correction (3) carried out on the laser beam before it is spatially filtered, and a measurement of the aberrations (7) on the laser beam. The phase of the beam is corrected so as to produce a beam having minimal aberrations after spatial filtering. The shielding device (D, D?) implementing this method may in particular be employed in apparatus using an intense laser beam of high (terawatt) peak power and in proton therapy units.

Abstract: The present invention relates to a high-power femtosecond pulsed laser, the laser including: a source able to generate a train of input laser pulses having an envelope frequency and a carrier frequency; a chirped pulse amplification unit; and, a unit for controlling the phase drift between the envelope frequency and the carrier frequency of the output laser pulses. According to the invention, the unit for controlling the phase drift between the envelope frequency and the carrier frequency includes electro-optical phase-modulation unit that are placed on an optical path of the chirped pulse amplification unit in order to stabilize the phase drift between the envelope frequency and the carrier frequency of the output laser pulses as a function of time.

Abstract: A method and passive device for the coherent combination of two amplified and/or spectrally broadened optical beams using at least one bidirectional optical component (A1, A2), the device includes an amplitude division ring interferometer having optical splitting and recombining elements disposed so as to receive an incident optical beam (S0) and to split it spatially into a first secondary input beam (H1) and a second secondary input beam (H2), optical guiding elements disposed so as to define an optical path in the form of a ring in the interferometer, the at least one bidirectional optical component being disposed on the optical path of the ring interferometer, the splitting and recombining elements being disposed in such a way as to receive and to recombine spatially, temporally and coherently the first secondary output beam (H1?) and the second secondary output beam (H2?), so as to form a coherent output beam.

Abstract: A chirped pulse fiber amplifier with nonlinear compensation, includes elements for generating a light pulse having an initial peak-power P0 and an initial duration T, a stretcher including at least one optical diffraction network having a line density higher than 1200 lines/mm and suitable for time-stretching the pulse and of inserting a time asymmetry in the stretched pulse, an amplifying fiber including a doped optical fiber section coupled with an optical pumping element and suitable for amplifying the stretched pulse for producing a pulse having a power, a compressor with optical diffraction grating suitable for time-compressing the amplified pulse so that the stretcher and the compressor are mismatched, the mismatch between the stretcher and the compressor being suitable for simultaneously compensating the second- and third-order nonlinear dispersions in the amplifying fiber during the propagation of a pulse having an initial power P0 through the chirped pulse amplifier.

Abstract: The present invention relates to a high-power femtosecond pulsed laser, the laser including: a source able to generate a train of input laser pulses having an envelope frequency and a carrier frequency; a chirped pulse amplification unit; and, a unit for controlling the phase drift between the envelope frequency and the carrier frequency of the output laser pulses. According to the invention, the unit for controlling the phase drift between the envelope frequency and the carrier frequency includes electro-optical phase-modulation unit that are placed on an optical path of the chirped pulse amplification unit in order to stabilize the phase drift between the envelope frequency and the carrier frequency of the output laser pulses as a function of time.

Abstract: A high-gain optical amplifier for a wave to be amplified at a wavelength referred to as the emission wavelength, includes: optical pumping elements (4) producing a pump wave at a wavelength referred to as the pump wavelength; a solid amplifying medium (1) that is doped with active ions, the solid amplifying medium being capable of emitting laser radiation at the emission wavelength when the medium is pumped by the pumping elements; cooling elements (2) capable of cooling the solid amplifying medium to a temperature of no higher than 250 Kelvin; and optical multiplexing elements capable of coupling together the pump wave and the wave to be amplified in the amplifying medium. The amplifying medium has Stark sublevels contained within a spectral domain ranging over less than 200 cm?1 (approximately 20 nm, when expressed in wavelength). A laser including a resonant optical cavity and an amplifier are also described.

Abstract: An ultra-short high-power light pulse source including a first laser pump source (1), a mode-locked laser oscillator (2), a second laser pump source (4), a waveguide (6) capable of inserting spectral phases into the light pulses, and a compressor (8) capable of generating predetermined spectral phases into the light pulses. The waveguide (6) includes an element capable of compensating the predetermined spectral phases generated at least by the compressor (8), the second laser pump source (4) being capable of delivering a second pump light flow (5) having a power PL such that the spectral phases generated by the wave guide (6) are opposed or quasi opposed to the predetermined spectral phases generated by the compressor (8) in order to generate compressed ultra-short light pulses (9) at the output of the compressor (8) with a planar or quasi planar spectral phase.

Abstract: A device for amplifying high-energy ultrashort light pulses, includes a generator (1), a first amplifying/time-stretching element (2) including a time-stretching element (3), a regenerative amplifier (4), a multipass amplifier (5) and a compressor (6). The device further includes a second amplifying/time-stretching element (11), arranged at the output of the generator (1), amplifying and time-stretching the initial light pulses (7) to generate amplified and time-stretched pulses (13), and a filtering element (12) arranged between the second amplifying/time-stretching element (11) and the amplification unit (2), blocking the low-amplitude light signals (14) of the amplified and time-stretched pulses (13).

Abstract: A high power solid-state non-regenerative optical amplification system (100) for amplifying a pulsed optical beam, includes a first optical amplification crystal (C1) and a second optical amplification crystal (C2) for amplifying the optical beam; optical pumping elements for longitudinal pumping amplification crystals (C1, C2); reflective optical elements (M?1, M?2, . . . , M?17) suitable for reflecting the optical beam so that the optical beam makes a total number of N sequential passes through the amplification crystals (C1, C2), wherein N is an integer and N>4. The reflective optical elements (M?1, M?2, . . . , M?17) are placed in a configuration suitable for alternatively interleaving the sequential optical beam passes through the 1st crystal (C1) and through the 2nd crystal (C2). A solid-state laser including the amplification system, and a method for amplifying a pulsed optical beam in a two-crystal multi-pass non-regenerative amplification system are also disclosed.

Abstract: A high power solid-state non-regenerative optical amplification system (100) for amplifying a pulsed optical beam, includes a first optical amplification crystal (C1) and a second optical amplification crystal (C2) for amplifying the optical beam; optical pumping elements for longitudinal pumping amplification crystals (C1, C2); reflective optical elements (M?1, M?2, . . . , M?17) suitable for reflecting the optical beam so that the optical beam makes a total number of N sequential passes through the amplification crystals (C1, C2), wherein N is an integer and N>4. The reflective optical elements (M?1, M?2, . . . , M?17) are placed in a configuration suitable for alternatively interleaving the sequential optical beam passes through the 1st crystal (C1) and through the 2nd crystal (C2). A solid-state laser including the amplification system, and a method for amplifying a pulsed optical beam in a two-crystal multi-pass non-regenerative amplification system are also disclosed.

Abstract: A chirped pulse fiber amplifier with nonlinear compensation, includes elements for generating a light pulse having an initial peak-power P0 and an initial duration T, a stretcher including at least one optical diffraction network having a line density higher than 1200 lines/mm and suitable for time-stretching the pulse and of inserting a time asymmetry in the stretched pulse, an amplifying fiber including a doped optical fiber section coupled with an optical pumping element and suitable for amplifying the stretched pulse for producing a pulse having a power, a compressor with optical diffraction grating suitable for time-compressing the amplified pulse so that the stretcher and the compressor are mismatched, the mismatch between the stretcher and the compressor being suitable for simultaneously compensating the second- and third-order nonlinear dispersions in the amplifying fiber during the propagation of a pulse having an initial power P0 through the chirped pulse amplifier.

Abstract: Method for shielding a high-power laser apparatus (S) in which a laser beam is generated and then amplified in at least a first amplification stage, including spatial filtering (4) of the amplified laser beam, phase correction (3) carried out on the laser beam before it is spatially filtered, and a measurement of the aberrations (7) on the laser beam. The phase of the beam is corrected so as to produce a beam having minimal aberrations after spatial filtering. The shielding device (D, D?) implementing this method may in particular be employed in apparatus using an intense laser beam of high (terawatt) peak power and in proton therapy units.

Abstract: An ultra-short high-power light pulse source including a first laser pump source (1), a mode-locked laser oscillator (2), a second laser pump source (4), a waveguide (6) capable of inserting spectral phases into the light pulses, and a compressor (8) capable of generating predetermined spectral phases into the light pulses. The waveguide (6) includes an element capable of compensating the predetermined spectral phases generated at least by the compressor (8), the second laser pump source (4) being capable of delivering a second pump light flow (5) having a power PL such that the spectral phases generated by the wave guide (6) are opposed or quasi opposed to the predetermined spectral phases generated by the compressor (8) in order to generate compressed ultra-short light pulses (9) at the output of the compressor (8) with a planar or quasi planar spectral phase.

Abstract: A device for amplifying high-energy ultrashort light pulses, includes a generator (1), a first amplifying/time-stretching element (2) including a time-stretching element (3), a regenerative amplifier (4), a multipass amplifier (5) and a compressor (6). The device further includes a second amplifying/time-stretching element (11), arranged at the output of the generator (1), amplifying and time-stretching the initial light pulses (7) to generate amplified and time-stretched pulses (13), and a filtering element (12) arranged between the second amplifying/time-stretching element (11) and the amplification unit (2), blocking the low-amplitude light signals (14) of the amplified and time-stretched pulses (13).

Abstract: A rare earth ion ultrashort laser source includes a resonant cavity having a first output face partially reflecting and a second reflecting face. The source also includes a first active material, which receives a pump luminous flux transmitted via a first solid laser pump source. The resonant cavity exhibits a length of optical path travelled by the pulses greater than 7.5 m so that the pulsed energy EL is greater than 100 nJ, the optical path including at least one passage in the active material and the ultrashort laser source includes elements for lengthening the resonant cavity thereby enabling to extend the length of the optical path travelled by the luminous pulses in the resonant cavity, the ABCD propagation matrix of the resonant cavity being close to the unit matrix so that the features of the luminous beam going back and forth in the resonant cavity remain unchanged.

Abstract: The invention relates to a rare earth ion ultrashort laser source including a resonant cavity (1) having a first output face (2) partially reflecting and a second reflecting face (3). Said source also comprises a first active material (4). Said first material (4) receives a pump luminous flux (6) transmitted via a first solid laser pump source (7). According to the invention, the resonant cavity (1) exhibits a length of optical path travelled by said pulses greater than 7.

Abstract: A wide-spectrum compact ultrabrief laser source includes a rare-earth ion primary laser. The source is pumped by a pump light flux centered on a wavelength ?D, the flux being emitted by a solid laser pump source. The primary source emits a primary light flux centered on a wavelength ?L of spectral width ??L. The latter is injected via an optical injection into a photonic crystal fiber having a length L, a cross-section d, and a set of cavities of diameter ?. A coupling optics collects the light flux at the output of the photonic crystal fiber. The light flux is centered on a wavelength ?F and has a spectral width ??F. The spectrum is subjected in the photonic crystal fiber to an enlargement which is due for more than 50% to phase self-modulation.