With the advent of high-energy-density (HED) experimental facilities, such as high-energy lasers and fast Z-pinch, pulsed-power facilities, millimeter-scale quantities of matter can be placed in extreme states of density, temperature, and/or velocity. This has enabled the emergence of a new class of experimental science, HED laboratory astrophysics, wherein the properties of matter and the processes that occur under extreme astrophysical conditions can be examined in the laboratory. Areas particularly suitable to this class of experimental astrophysics include the study of opacities relevant to stellar interiors, equations of state relevant to planetary interiors, strong shock-driven nonlinear hydrodynamics and radiative dynamics relevant to supernova explosions and subsequent evolution, protostellar jets and high Mach number flows, radiatively driven molecular clouds and nonlinear photoevaporation front dynamics, and photoionized plasmas relevant to accretion disks around compact objects such as black holes and neutron stars.

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Experimental astrophysics with high power lasers and Z pinches

Nonlinear Optical Crystals: A Complete Survey

Piezoelectric materials that can function at high temperatures without failure are desired for structural health monitoring and/or nondestructive evaluation of the next generation turbines, more efficient jet engines, steam, and nuclear/electrical power plants. The operational temperature range of smart transducers is limited by the sensing capability of the piezoelectric material at elevated temperatures, increased conductivity and mechanical attenuation, variation of the piezoelectric properties with temperature. This article discusses properties relevant to sensor applications, including piezoelectric materials that are commercially available and those that are under development. Compared to ferroelectric polycrystalline materials, piezoelectric single crystals avoid domain-related aging behavior, while possessing high electrical resistivities and low losses, with excellent thermal property stability. Of particular interest is oxyborate [ReCa4O (BO3)3] single crystals for ultrahigh temperature applications (>1000°C). These crystals offer piezoelectric coefficients deff, and electromechanical coupling factors keff, on the order of 3–16 pC/N and 6%–31%, respectively, significantly higher than those values of α-quartz piezocrystals (~2 pC/N and 8%). Furthermore, the absence of phase transitions prior to their melting points ~1500°C, together with ultrahigh electrical resistivities (>106 Ω·cm at 1000°C) and thermal stability of piezoelectric properties (< 20% variations in the range of room temperature ~1000°C), allow potential operation at extreme temperature and harsh environments.

Piezoelectric Materials for High Temperature Sensors

Laser-plasma accelerators can produce high-energy electron bunches over just a few centimetres of distance, offering possible table-top accelerator capabilities. Wang et al. break the current 1 GeV barrier by applying a petawatt laser to accelerate electrons nearly monoenergetically up to 2 GeV.

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Quasi-monoenergetic laser-plasma acceleration of electrons to 2 GeV

In the 2015 review paper 'Petawatt Class Lasers Worldwide' a comprehensive overview of the current status of highpower facilities of >200 TW was presented. This was largely based on facility specifications, with some description of their uses, for instance in fundamental ultra-high-intensity interactions, secondary source generation, and inertial confinement fusion (ICF). With the 2018 Nobel Prize in Physics being awarded to Professors Donna Strickland and Gerard Mourou for the development of the technique of chirped pulse amplification (CPA), which made these lasers possible, we celebrate by providing a comprehensive update of the current status of ultra-high-power lasers and demonstrate how the technology has developed. We are now in the era of multi-petawatt facilities coming online, with 100 PW lasers being proposed and even under construction. In addition to this there is a pull towards development of industrial and multidisciplinary applications, which demands much higher repetition rates, delivering high-average powers with higher efficiencies and the use of alternative wavelengths: mid-IR facilities. So apart from a comprehensive update of the current global status, we want to look at what technologies are to be deployed to get to these new regimes, and some of the critical issues facing their development.

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Petawatt and exawatt class lasers worldwide

The Mercury laser will be used to pump a high average power Ti:sapphire chirped pulse amplifier which will produce a compressed peak power >1 petawatt at 10 Hz.

Design of a 10 Hz Femto-Petawatt Laser Pumped by the Mercury Laser Facility

We have demonstrated a high-gain optical parametric chirped-pulse amplifier for Nd:glass-based short-pulse laser systems based on periodically poled potassium-titanyl-phosphate. Our amplifier produced high single-pass gain, broad bandwidth, excellent beam quality and stability.

High-beam-quality optical parametric chirped-pulse amplification in periodically-poled KTiOPO4

Summary form only given. Yb-doped Sr/sub 5/(PO/sub 4/)/sub 3/F (S-FAP) has already been demonstrated as an ideal laser material for medium power applications in a diode-pumped solid-state laser oscillator and high repetition rate amplifier system. Ytterbium has a simple electronic structure in the near infrared leading to a low quantum defect, excited state absorption, and nonradiative decay. S-FAP lasers at 985 nm can be efficiently pumped by diodes at 900 nm and have the added advantage of a low quantum defect (0.09) yielding efficient diode pumped operation. In addition, the advent of an efficient diode-pumped, doubled S-FAP laser at 492.5 nm represents an attractive blue light source.

Q-switched Yb/sup 3+/:Sr/sub 5/(PO/sub 4/)/sub 3/F three-level laser operation at 985 nm and efficient doubling at 492.5 nm

We describe an electro-optically Q-switched, diode-pumped Nd:YAG slab laser oscillator operating at an average power of greater than 250 watts. More than 100 watts of frequency doubled light has been demonstrated.

250 Watt Average Power Electro-Optically Q-Switched Diode-Pumped Power Oscillator

Summary form only given. The physical robustness of the GdCOB family of nonlinear crystals has attracted interest in these materials in applications involving high-average power. Large crystal growth of these materials is relatively easy, they readily and quickly accept a high quality optical polish, and are non-hygroscopic. High average power conditions encountered in intracavity frequency conversion makes desirable an intracavity converter crystal that has low angular and temperature sensitivities. We report values of the thermal sensitivity, /spl beta//sub T/=(/spl delta//spl Delta/k//spl delta/T), and angular sensitivity, /spl beta//sub /spl theta//=(/spl delta//spl Delta/k//spl delta//spl theta/), for LBO, GdCOB, and LaCOB as determined from experiment.

Thermal sensitivities and d/sub eff/'s for second harmonic generation (SHG) In LaCa/sub 4/O(BO/sub 3/)/sub 3/ (LaCOB) and GdCa/sub 4/O(BO/sub 3/)/sub 3/ (GdCOB) compared to LiB/sub 3/O/sub 5/ (LBO)

Christopher A. Ebbers

Papers

Design of a 10 Hz Femto-Petawatt Laser Pumped by the Mercury Laser Facility

High-beam-quality optical parametric chirped-pulse amplification in periodically-poled KTiOPO4

Q-switched Yb/sup 3+/:Sr/sub 5/(PO/sub 4/)/sub 3/F three-level laser operation at 985 nm and efficient doubling at 492.5 nm

250 Watt Average Power Electro-Optically Q-Switched Diode-Pumped Power Oscillator

Thermal sensitivities and d/sub eff/'s for second harmonic generation (SHG) In LaCa/sub 4/O(BO/sub 3/)/sub 3/ (LaCOB) and GdCa/sub 4/O(BO/sub 3/)/sub 3/ (GdCOB) compared to LiB/sub 3/O/sub 5/ (LBO)