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In this paper, the characteristics and range of application of the Martinez and the Offner stretchers in a chirped pulse amplifier system is analyzed theoretically for a multiple-pass amplifier and a regenerative amplifier respectively. The Martinez stretcher can completely compensate the dispersion introduced either from a multiple-pass amplifier or from a regenerative amplifier within a certain bandwidth. In a regenerative amplifier, if it is necessary to obtain broader pulses, the compact Offner stretcher can be applied.

A tunable diode-pumped Cr:LiSAF regenerative amplifier has been demonstrated for the first time. Femtosecond pulses have been amplified to pulse energies exceeding 1 mu J at repetition rates up to 16 kHz. >

We report on a side-pumped Nd:phosphate laser regenerative amplifier that delivers laser pulses of as much as 100 mJ in a single TEM mode. The laser beam is mode matched to the amplification medium by an intracavity fused-silica phase plate for mode shaping and a telescope for adjustment of the beam mode to the amplification rod section such that most of the energy stored in the rod is transferred to the laser pulses. As a result of the good overlap and the low loss, an optical-to-optical conversion efficiency of as much as 10% was measured for a pumping current of 80 A and greater than 100-mJ output pulses.

We measured the timing error of femtosecond pulses amplified by a Ti:sapphire regenerative amplifier operated at a 1 kHz repetition rate using a modified cross-correlation technique. This technique can detect sub-femtosecond timing variation. By actively controlling the amplifier cavity length, we reduced the rms timing jitter of the regenerative amplifier into the sub-femtosecond range.

We used the Nd:YLF Oscillator/Regenerative Amplifier Laser (ISL, San Diego, Calif) at 1053 nm to perform peripheral iridotomies in three eyes. The total amount of energy required was greater than the usual amount needed in Nd:YAG peripheral iridotomies. However, each laser pulse uses a much smaller quantity of laser energy and produces a smaller and more refined optical breakdown. The postoperative courses for these patients were uneventful, without postoperative intraocular-pressure spike or increasing anterior-chamber reactions.

International audience; 30-fs pulses at 1.22 µm are produced by a self-mode-locked Cr:forsterite laser and amplified in a Cr:forsterite regenerative amplifier by a chirped-pulse amplification technique. 54-fs, 1-GW pulses at a 1-kHz repetition rate are obtained.

To achieve high output energy by generating a large gain mode volume, a Nd:phosphate glass ring regenerative amplifier with a built-in 1:1 telescope was proposed as a part of a terawatt chirped-pulse amplification Nd:glass laser, and its performance was characterized. In this ring regenerative amplifier, an input energy of 80 pJ could be amplified up to 33 mJ, and the output beam size was 2.3 mm in width and 2.0 mm in height. The amplified spectrum showed that high amplification could be obtained without a noticeable gain narrowing from the injected spectrum of 6 Å bandwidth.

An all solid-state laser system based on sum-frequency mixing the signal wave from an optical parametric generator and the fourth harmonic of a Ti:sapphire regenerative amplifier produced ≃200 fs long nearly bandwidth-limited pulses tunable from 172 down to 166 nm.

We describe the design of a continuously tunable Ti:sapphire regenerative amplifier that is capable of sustaining amplification over a wavelength range from 730 nm to more than 800 nm. The amplifier cavity is tuned with a prism pair in combination with a spherical mirror. It sustains an oscillation bandwidth of 5 nm and produces a chirped output pulse energy of 1.2 mJ compressible to a duration of 140 fs at 745 nm. We present a calculation of the theoretical bandwidth.

A diode-pumped Nd:fluorophosphate regenerative amplifier was developed. Chirped seed pulses were amplified to 24 muJ at repetition rates to 1 kHz and to 5 muJ at a 10-kHz repetition rate. On compression, 850-fs pulses were obtained. White-light continuum generation was observed when these pulses were focused into a glass sample. Furthermore, based on a rate equation analysis, the effects of the gain material lifetime on the pulse energy at high repetition rates are discussed.

An all-solid-state tunable diode-pumped Cr3+:LiSrAlF 6 (Cr:LiSAF) regenerative amplifier, seeded by a tunable diode-pumped Cr:LiSAF femtosecond oscillator, has been demonstrated for the first time to our knowledge. The oscillator was tunable over 75 nm and generated pulses as short as 24 fs. As much as 70 mW average output power was obtained with pulses of 40-fs duration. The amplifier produced recompressed pulses of less than 200-fs duration with energies exceeding 1 μJ at a repetition rate as high as 25 kHz.

We describe a high-power compact diode-pumped Nd:YLF regenerative amplifier. The pumping source is a 15-W diode-laser array that is focused into the laser crystal with a longitudinal end-pumping arrangement based on an array of cylindrical microlenses. Seeded with 15-ps pulses from a diode-pumped and mode-locked Nd:YLF oscillator, the regenerative amplifier produces pulses of 0.5-mJ energy at a 1-kHz repetition rate. A pulse energy as high as 0.75 mJ is achieved at a 500-Hz repetition rate and below.

Ultrashort 90-fs 8-TW Fourier-transform-limited pulses are generated with chirped pulse amplification in a Cr3+:LiSrAlF6 laser system incorporating a regenerative amplifier and three additional double-pass amplifiers with increasing aperture up to 25 mm.

We have developed a cw krypton-ion-laser-pumped Cr(3+):LiSrAlF(6) regenerative amplifier for femtosecond pulses operating at a 5-kHz repetition rate. After recompression, we obtained 3.6-microJ, 170-fs pulses at 825 nm. By focusing these pulses in a cell of water, we generated a white-light continuum.

A mode-locked Nd-glass laser oscillator with intra-cavity pulse selection by a Pockels cell shutter is described. A regenerative amplifier system with a saturable absorber is used to shorten the selected light pulses from the master oscillator. Pulses were shortened from 8 ps to 1 ps.

Active-mirror amplifiers have been demonstrated to be viable amplifiers for use in high peak power/energy Nd:glass laser systems [1], [2]. In addition to having a rather large storage efficiency, they may be used in systems requiring a medium-repetition rate and possess desirable thermal properties for application in double-passed or regenerative amplifier architectures. Here, we review recent progress made in the development and deployment of active-mirror amplifiers, examine their potential storage and overall system efficiencies, and outline the technological progress needed for their development as high-repetition rate (1-10 Hz) amplifiers.

A practical dye laser system producing high-repetition rate/ (1kHz) amplified tunable/ (585-624nm) femtosecond/ (500fs) pulses and a compression to 29fs are described. The system consists of a hybridly mode-locked dye oscillator and a dye amplifier pumped by a frequency-doubled CW mode-locked Nd: YAG oscillator and regenerative amplifier output. The frequency tunable output pulses of 500fs duration and 500kW peak power are further compressed to 29fs by using a fiber grating compressor.

A single 30 ps pulse from a passively mode-locked Nd:YAG oscillator was synchronized with a longer pulse of 3–5 ns from a Nd:YAG regenerative amplifier. Jitter between the two pulses was found to be negligible over a wide range of energies injected into the regenerative amplifier.

A 200 joule TEA-CO 2 laser has been mode-locked by injection of a nanosecond pulse into a regenerative amplifier operating in an above threshold regime. 25 gigawatt pulses have been obtained.

A pulse regenerative amplifier is a bistate circuit which introduces gain and pulse reshaping in a pulse transmission or digital data processing system. Frequently it is used also to retime the pulses which constitute the flow of information in such systems. The small size, reliability, and low power consumption of the transistor have led naturally to the use of the transistor as the active element in the amplifier. It is the purpose of this paper to describe some of the techniques that are pertinent to the design of synchronized regenerative amplifiers operating at a pulse repetition rate of the order of one megacycle per second. An illustrative design of an amplifier for use in a specific digital computer is presented.

The metal tube here described (designated type DCM-1) is established as a practical design, suitable for production. It can be used as a converter in the wavelength range of 25 to 30 centimeters, and as an oscillator with a power output of 1 to 5 watts in the wavelength range of 30 to 60 centimeters. It can also be employed as an amplifier with an amplification coefficient K of 3 to 4 at a wavelength of 25 centimeters, or with a K of 6 to 7 at λ of 40 centimeters. If used as a regenerative amplifier, a K of 10 can be secured at λ of 25 centimeters, and a K of 15 at λ of 40 centimeters.

We have developed a new dye laser and c.w.-pumped regenerative amplifier system capable of generating white light continuum at a repetition rate higher than 1 KHz.

Many recent developments in picosecond pulsed-laser technology have been motivated by the need for higher sensitivity, better measurement precision and, above all improved and reliable time-resolution in the study of primary photoprocesses. Although solid-state lasers are advantageous to us because of their intrinsic high power, they suffer from instability and the need to compromise between repetition-rate and pulse-duration.

This volume of the LLE Review, covering the period January-March 1988, contains articles on the spectra of scattered laser radiation from laser-produced plasmas and on the bounce coating of ablation layers on fusion targets. The advanced technology section has reports on a novel technique for characterizing surface breakdown on semiconductor devices and on a versatile alexandrite regenerative amplifier. Finally, the activities of the National Laser Users Facility and the GDL and OMEGA laser facilities are summarized.

Progress in short pulse generation in the visible and near infrared spectral regions has traditionally resulted from improvements in actively or passively mode-locked lasers. At other frequencies, however, this need not be the case. Although not usually explicitly stated, a high power picosecond (or subpicosecond) visible pulse can be used in conjunction with any of a number of nonlinear techniques to generate low power pulses of similiar duration over all the visible, near or mid-infrared spectral region.

An optically pumped, submillimeter wavelength, waveguide laser has been designed to operate as a regenerative amplifier. Small-signal gains of 9 dB have been measured for cw operation on the 372.8 μm transition of CH 3 CN. System design and operating characteristics of the oscillator-amplifier configuration are described.

We demonstrate phase-controlled pulse-burst amplification based on differentialpathlength stabilization between the master oscillator and the amplifier cavities. This techniqueboosts the safe level of extractable burst energy and suppresses fluctuations in various burst-modeapplications.

A Cr:forsterite (Cr4+:Mg2SiO4) ring regenerative amplifier pumped by a pulsed Nd:YAG laser is developed which provides the amplification of 1240-nm femtosecond pulses from a master oscillator up to energy of 450 μJ. The amplified pulses propagating with a pulse repetition rate of 10 Hz were compressed in a compressor (with transmission 75%) down to 70 fs, corresponding to the 4-GW peak power.

A large number of Yb3+-doped laser crystals are investigated as active media for ultrafast oscillators and amplifiers in last decades. Yb:CALGO (Yb:CALYO) crystals demonstrate promising spectroscopic properties that confirmed by excellent experimental results in mode-locked lasers provided near-transform limited pulses with wide spectra (up to 51nm [1]). Despite this the large number of investigated femtosecond Yb-based regenerative amplifier (RA) systems were seeded by fs-pulses with narrower spectrum (≤15nm [2]) that can limit the amplified pulse bandwidth. In our paper we present for the first time to the best of our knowledge the results of experimental investigation of Yb:CALYO-based chirped pulse RA seeded by broad-band (60 nm FWHM) pulses.

The aim of this work is to propose new laser architectures based on optical parametric chirped pulse amplification (OPCPA). Common goals of OPCPA pre-amplifiers are to reach high energy level while maintaining the spectrum width and to adapt geometry of the amplified beam to the high power laser chain optics. In this work, we consider OPCPA as a way to control and to sculpt ultrashort laser pulses. Our first set-up aims to compensate for the weak time recovery default between pump and signal pulses, which lowers the energy extraction. We demonstrate that a regenerative OPCPA, resonant on the idler wave, satisfy this requirement but also produce a high-intensity and high-repetition rate train of amplified signal replicas. Our second laser system pre-compensates the spectral gain narrowing by sculpting pulses directly within the OPCPA section, where a temporal shaping of the pump beam permits a spatio-spectral shaping of the amplified signal. Finally, we propose an OPCPA based on spatial coding and uniform amplification of different spectral components of the signal wave. This is achieved using a fan-out periodically poled crystal inserted in a zero dispersion line., Dans le cadre d'études menées autour du programme PETAL, nous avons développé de nouvelles architectures pour la pré-amplification d'impulsions par amplification paramétrique optique à dérive de fréquence (OPCPA). Dans ce travail, nous considérons l'OPCPA comme un moyen de contrôle et de mise en forme des impulsions. Nous suggérons trois architectures lasers qui aspirent chacune à répondre à des défauts de la technique OPCPA ou des chaînes dédiées à la FCI. Ainsi, nous pallions un possible défaut de recouvrement temporel entre les impulsions pompe et signal, lequel induit une mauvaise extraction d'énergie lors du processus paramétrique. Dans ce cadre, nous avons démontré qu'une cavité régénérative OPCPA, résonnante sur l'onde complémentaire, permet d'optimiser l'amplification. Au-delà ce système permet de produire un train de répliques amplifiées de l'onde signal. Notre second montage vise à pré-compenser le rétrécissement spectral par le gain en façonnant les impulsions signal au niveau de l'étage OPCPA dans les domaines spatial et spectral. Nous avons démontré que ceci pouvait être réalisé en mettant en forme temporellement et spatialement le faisceau pompe. Enfin, nous proposons un OPCPA basé sur l'adressage spatial et l'amplification uniforme des composantes spectrales dans un cristal à polarisation périodique de type éventail.

We present an analysis of multi-periodic and chaotic operation regimes of regenerative amplifiers. Numerical results were confirmed experimentally with a diode-pumped Yb:glass regenerative amplifier generating a maximum pulse energy of 620μJ.

The 100-kHz, 100-W, Yb:YAG thin-disk regenerative amplifier pumps the parametric mid-IR source. The OPG stage (PPLN) is followed by OPA stages (KTP). The idler of 2.2 µm wavelength is taken from final amplifier.

Ultra short pulse down to 100 fs has been obtained in a regenerative amplifier using Yb doped CALGO crystals. By employment of nonlinearity we succeed to overcome gain narrowing limitation.

We report on a broadband, picosecond two-stage optical parametrical chirped pulse amplification system, pumped at 515 nm by a frequency doubled Yb regenerative amplifier. The system, designed to be part of the new petawatt picosecond front end, delivers $30\text{ }\text{ }\ensuremath{\mu}\mathrm{J}$ pulses at a central wavelength of 870 nm with about 200 nm bandwidth at 100 Hz. The overall efficiency of the system (pump signal) is 8% while the second stage presents $\ensuremath{\sim}17%$ conversion efficiency.

We report 190-mJ pulses with spectral content supporting sub-ps pulse-duration at a 10 Hz repetition rate generated by a cryogenically-cooled, bulk Yb:YLF laser amplifier system. The amplifier system relies on a chirped pulse amplification architecture and consists of a fiber front-end, a regenerative amplifier, and two 4-pass amplifiers. The fiber front-end delivers 15-nJ, 1-ns stretched seed pulses, which are first amplified to 13-mJ pulse energy inside a Yb:YLF regenerative amplifier. Then the pulses are boosted further to 115 mJ and 190 mJ in two consecutive 4-pass amplifiers. To our knowledge, these are the highest pulse energies reported from Yb:YLF based amplifiers to date. We foresee shortening the pulsewidths to sub-400-fs range in future studies.

We report on a new approach to measure the accumulated B-integral in the regenerative and multipass amplifier stages of ultrashort-pulse high-power laser systems by B-integral-induced coupling between delayed test post-pulses and the main pulse. A numerical model for such non-linear pulse coupling is presented and compared to data taken at the high-power laser Draco with self-referenced spectral interferometry (SRSI). The dependence of the B-integral accumulated in the regenerative amplifier on its operation mode enables optimization strategies for extracted energy vs. collected B-integral. The technique presented here can, in principle, be applied to characterize any type of ultrashort pulse laser system and is essential for pre-pulse reduction.

A new type of gas plasma oscillations is reported, obtained by shunting the plasma with an external capacitor. This configuration can work as an oscillator or as a regenerative amplifier.

Pulses of 37-psec duration are generated by a cw actively mode-locked Nd:YLF oscillator and subsequently amplified to 2.5 mJ in a cw-pumped Nd:YLF regenerative amplifier operating at a repetition rate of 500 Hz. In comparison, the same system refitted with Nd:YAG gain media produces longer pulses (~80 psec) with lower energy (1 mJ).