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A high‐power, Q‐switched, neodymium‐doped glass laser was used to create a blow‐off plasma at surfaces of solid materials. Measurements of the ensuing stress pulses and the associated phenomena are discussed.

The evolution of a picosecond optical pulse in a mode‐locked Nd : glass laser is primarily affected by the construction of the resonator components. By paying attention to what have been thought of as minor details in the design of the laserhead, such as mounting of the flashlamps and laser rod, virtually 100% reliability and remarkable reproducibility have been achieved. Furthermore, we have studied how the pump power, mirror alignment, and saturable dye concentration affect the reliability and have found that these parameters must be critically controlled if reproducibility is desired.

Self‐focusing damage in a pattern of Fresnel fringes is observed in the final element of a high‐power glass laser amplifier as the result of the truncation of a Gaussian input beam. Detailed calculations give good agreement with the location and pattern of damage.

A recently introduced technique, the ultrahigh-speed photography of ps light pulses, was used to study the dependence of the pulse duration of a passively Q-switched Nd +3–glass laser on the cavity length and the dye transmission. A constant duration, within the experimental error, was found.

Microwave sound of discrete frequencies has been generated by the irradiation of a solid with the uniformly spaced, ultrashort optical pulses produced by a mode‐locked Nd:glass laser. The sound, rich in harmonic content, has its fundamental frequency fixed by the repetition frequency of the laser pulses. Believed to be thermally generated in the optical skin depth where the energy is absorbed, the sound has been detected at room temperature up to 2 GHz, the tenth harmonic of the fundamental repetition frequency. Such high harmonic content indicates that the acoustic pulses have rise times significantly less than 1 nsec and demonstrates the feasibility of utilizing ultrashort laser pulses to produce ultrashort acoustic pulses.

A new technique for measurement of picosecond light pulses is described using the unique polarization properties of optical third harmonic generation. A width of half‐maximum intensity less than 0.73 psec is observed for a mode‐locked neodymium glass laser.

Short-wavelength lasers offer great advantages in absorption and implosion properties. We have performed large-scale implosion experiments using green beams from our Gekko IV four-beam Nd: phosphate glass laser. The experimental results are compared with similar work with 1-µm laser light. The green light data show that neutron yield and implosion uniformity are improved.

The use of short intensive Nd:glass laser pulses focused into the opaque regions of eyes with cataracts to evaporate or plasmatize these regions and then reach clean and optically transparent areas has been developed on two different scales of pulse lengths. According to the availability of the present laser technology, one regime is the Q- switch pulse technique with nanosecond pulses, and the other is the mode-locked laser pulse technique with pulses of a few picosecond duration.

The research program at SOREQ is devoted to the study of laser produced plasmas and laser produced shock waves. For these purposes a set of different oscillators were developed and an Nd:glass laser system was contructed. The experiments were conducted with 1.06µm laser light pulses in the range of irradiances from 1012 to 1016 W/cm2.

This paper describes results obtained on annealing Si‐implanted GaAs with a Q‐switched Nd:Glass laser. Studies were made on as implanted and laser annealed samples using optical absorption measurements, SIMS, sheet resistance measurements, and Hall measurements. The results were compared with those obtained using thermal annealing.

This paper presents the design of the four-channel Nd: glass high power laser system in the Kaliski Institute of Plasma Physics and Laser Microfusion (IPPLM) in its optimized version, based on a theoretical analysis of propagation of radiation in the real laser channel.

In the pursuit of laser fusion, the Lawrence Livermore Laboratory (LLL) has undertaken a broad program of glass laser development and construction. This paper reviews the history of this effort,1 and indicates its future thrust. The CYCLOPS, JANUS, ARGUS, and SHIVA lasers are described, and possible larger lasers are discussed.

The elements of a Nd: Glass laser chain as it is constructed for fusion experiments are described. A brief overview of the ARGUS and SHIVA systems employing Nd lasers is given. (MOW)

The basic requirements for an x-ray laser are discussed. Consideration is given to producing soft x-ray laser action by focussing high power radiation from an Nd: glass laser on solid targets. equirements for x-ray laser gain, pump power and the volume of the laser medium are derived. The feasibility of soft x-ray lasers is compared to that of hard x-ray lasers. Proposed methods to create inversion and current experimental efforts are described.

Recent development of an ultrafast electro-optic deflector (EOD) has revealed that the EOD can be utilized to generating picosecond pulses from continuous light [1], an optical streak camera [2], a picosecond optical Fourier transformer [3], and so on. Here, we propose to use the EOD as an active modelocking modulator. Its loss modulation property is better than other modelocking modulators used ever. Stable l0ps pulses were experimentally generated from a purely active mode-locked Nd:glass laser using the EOD.

The present stage of the development of a picosecond TW-class glass laser system is briefly described. Results of both experimental and theoretical studies of X-ray generation from picosecond laser-produced plasmas are described.

A survey of single-pulse laser damage thresholds for a wide variety of commercially available film coatings and prepared surfaces is reported. Tests were conducted at 532, 355, and 248 nm. Pulses for the longer wavelengths, generated by harmonic conversion of 1064-nm light from a Nd:glass laser, had a duration of 0.7 nsec. The 248-nm pulses had a 20-nsec duration and were produced by a KrF laser.

A two-branch passively mode-locked Nd-glass laser is applied to generate light pulses down to 0.4 ps duration (average duration 0.9 ps). The laser action is initiated in a path of high saturable dye transmission and then switched to a branch of low saturable dye transmission for efficient pulse compression. The experimental results are compared with computer simulations.

An apparatus to produce layers of liquid and/or solid deuteriumtritium inside glass and polymer hollow spherical pellets is described. Such pellets have been used as cryogenic targets in neutron-producing experiments with the KMSF Nd:glass laser. Extensive experiments under cryogenic conditions were performed to determine the state and form of the thermonuclear fuel at the moment of arrival of the laser pulse in target-interaction experiments.

Laser-driven inertial confinement fusion utilizing direct drive techniques will require on-target intensity profiles which are carefully controlled. Current ignition target designs require that the intensity on target should depart by

While the stability of passively mode locked Nd:YAG lasers has been greatly improved in recent years through addition of intracavity acoustooptic loss modulators, relatively little attention has been given to the Nd:glass laser, especially in the very short pulse regime [1–6]. In the hybrid mode locking approach, the active loss modulation reduces the inherent statistical nature of the early-stage pulse build up, while retaining the effect of the saturable absorber as nonlinear loss element and Q switch for final-stage pulse shortening. We have investigated use of the new fast-relaxing saturable absorbing dye Eastman #5 in active-passive mode locking of an Nd:phosphate glass laser. Its use has led to stable mode-locking performance and generation of ~ 6ps duration pulses, largely free of occurrences of satellite pulse structure.

In January 1986 the Vulcan1 high power Nd Glass laser facility at the Rutherford Appleton Laboratory will be used in a series of experiments to investigate the generation of Beat‐Waves in a Z‐pinch plasma. The experimental campaign is being conducted in collaboration with the Plasma Physics Group at Imperial College, London.

We now begin an investigation of what may be regarded as the central problem in the design of high-peak power Nd:glass laser systems. The phenomena of self-focusing, discovered when high-power lasers first became available, presently limits the output of every laser system designed to operate at short (50–200 ps) pulse widths. Although the problem has yielded to a number of improvements in laser materials, most notably the development of low-nonlinearindex glasses (Chap.2), it is fair to say that the major developments leading to present-day laser systems that deliver multi-terawatt performance per beamline are due to the excellent work of colleagues at the Lawrence Livermore Laboratory. In particular, they deserve credit for such concepts as spatial filtering and imaging, to be treated in detail below; but, more importantly, the major advancement is in our understanding of the nonlinear effects, well known to the experimentalist in this area. Although the basics of self-focusing theory (Sect.7.2–4) were known for some time previous to the advent of the construction of large Nd:glass laser systems, the major contribution here is the development of semi-phenomenological theories that enable the laser designer to proceed with a great degree of confidence and reliably predict the operating characteristics of such a system. As is usually the case with systems of such complexity, it is impossible to simulate the exact physics in detail because it would call for a computational capability and expense that is beyond the resources of any single laboratory. Consequently, what we present in Sects.7.2–6 below is the current phenomenological understanding that has led to multi-terawatt performance of a number of laser systems in this country and abroad.

We now turn our attention to a subject that is interesting from a fundamental-physics standpoint as well as extremely important in the design of large Nd: glass laser systems, namely optically induced damage to dielectric materials. The subject has attained considerable importance because, if permanent irreversible damage occurs in such systems, it is expensive to replace the damaged component and may lead to (if not replaced) a gradual degradation of performance. Furthermore, certain staging schemes, particularly for long pulses, are intended to run at as large a flux as possible, which is limited by the damage threshold of the component in question. The aperture or diameter of a stage is often determined by the damage threshold of the limiting component in the stage; because the cost of a component is a strong function of the diameter it is obviously of interest to obtain the maximum damage threshold to minimize the diameter. Although the general subject of optically induced damage has matured considerably in recent years, progress has been slow owing to the experimental and theoretical complexities. At the present time, workers in the field cannot even agree on the basic physical cause of optical damage; it is likely that a number of separate mechanisms are involved. Such disagreements have not impeded progress, however; much of the work in this area is experimental and empirical and has yielded a number of practical results of immediate importance, particularly in the inertial-confinement fusion community.

Saturation of the optical absorption near the bandedge in the ternary semiconductor alloy systems InAsxPl−x and Gal−yIny As been studied using mode locked pulses frog a Nd:glass laser. Transmission levels exceeding the linear value by more than 4 orders of magnitude have been observed. Time dependent measurements show that the absorption can recover in times of the order of 30 psec, indicating that these materials may be useful as mode locking saturable absorbers for infrared lasers.

OCTAL (Figure 1) is an eight beams Neodymium Silicate glass laser working in the 2 TW and 1 kJ region with pulse durations ranging from 30 ps to a few ns.© (1979) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The performance of a passively mode-locked Nd-glass laser with an intracavity solid etalon is studied. For a 0.1 mm thick uncoated fused silica plate maximal spectral broadening (factor 4 to 5) and temporal pulse shortening (factor 1.5 to 2) is achieved at a tilting angle of τ43°. Theoretical analysis of temporal pulse development agrees with experimental findings.

Time resolved transmission (λ = 1060 nm) and reflectivity (λ = 632.8 nm) during 20 nsec Nd:glass laser annealing in ion implanted Si were measured to study dynamic behaviors of laser annealing. Transmitted laser energy was also measured to complement transient measurements. Transient transmitted light intensity was found to be almost completely quenched as would be expected from absorption by a molten Si layer.

Nova is a ten beam high power Nd:glass laser used for interial confinement fusion research. It was operated in the high power high energy regime following the completion of construction in December 1984. During this period several interesting nonlinear optical phenomena were observed. These phenomena are discussed in the text. 11 refs., 5 figs.

This book is concerned with the physics of high-power Nd:glass lasers. To understand the design and operation of such devices we first explore the fundamental physics of the trivalent rare-earth Nd ion in various glass and crystalline hosts. It is worthwhile pausing here to understand the reasons for Nd:glass becoming the predominant optical material to be used today.

The first 6 of 24 beams in the Omega laser system have been converted from infrared to ultraviolet. This was accomplished by installing third harmonic generator (THG) crystals to triple the frequency of the incident 1ω (1054-nm) red to 3ω (351-nm) blue light.

Proper laser infrared irradiation of ball targets 10 to 100 ..mu..m in diameter requires micrometre-step positioning of the system's optical elements. A central control console has been designed that gives the operator nearly complete control of this complex operation. Twin alignment lasers can be operated from the console. Devices can be inserted in the beam lines, mirrors moved, and the target ball aligned, all with fine precision. The focus position can be viewed by closed-circuit TV monitors; disk recording of the TV waveforms is available. The main capacitor banks can be charged for rod shots. Communications with laser operators can be maintained by intercom or radio, and video signals can be sent to remote areas. The console has been instrumental in saving many hours of manual labor.

Laser driven implosion experiments performed at Limeil with the four beams emitted by our Nd glass laser system C6 in nanosecond range and at incident laser flux less than 1014 W/cm2 are related.

A military eye-safe rangefinder based on a Er3+: glass Q — switched laser is described. The output energy of the laser is up to 50 mJ with a pulse duration of ~ 25 ns. Under typical operating conditions the expected range of the system may be up to ~ 5 Km.

The development of the high-power laser system for laser plasma research in China is reported. The parameters of a six-beam laser system and a 1011-W single-beam Nd:glass laser system, as well as some results of the laser plasma experiments, will be discussed.

The design of a neodymium glass laffr system for irradiation of targets of 10 -1012 watt pulses in a high brightness beam requires simultaneous solution of a number of technical problems. These problems can be separated into two areas relating to self focusing and to target and interstage isolation in the system.© (1974) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In the previous seven chapters we have treated, in as much detail as possible in a book such as this, the important physics relevant to the design of Nd: glass laser systems. This final chapter will concentrate on applying what we have learned to the actual design of real laser systems operating in the short-pulse, high-peak-power regime when output is limited by nonlinear effects. Although it will become apparent that the subject matter preceding this chapter will be very relevant to the task at hand, we here introduce another variable to an already complicated problem — namely, cost. In recent years, the cost associated with building large laser devices for laser-fusion experiments has assumed great importance and must be factored into the overall laser-design process. Indeed, methods have been developed that optimize system performance and cost for both the short-pulse (high-peak power) and the long-pulse (high-energy) regimes. Although we will treat here only the design of the high-peak-power systems, the optimization procedure for high-energy systems is straightforward and, in fact, much simpler.

A manual, prepared to guide personnel in operating and maintaining the Janus glass laser system, is presented. System components are described in detail. Step-by-step procedures are presented for firing the laser and for performing routine maintenance and calibration procedures.

The emission spectra of phthalocyanine single crystals and evaporated thin films have been investigated in the near infrared region. These emission spectra are discussed in connection with S-T interaction caused by central metal atoms. Dependence of induced current on ruby and glass laser intensity shows that the triplet state plays an important role in the carrier generation in the near infrared region.