The MTW, shown schematically in Fig. 1, is a single-beam, hybrid chirped-pulse–amplification laser system. It combines optical-parametric amplification (OPA) with neodymium (Nd)-doped laser-glass amplification to produce compressed output-pulse energies limited only by the damage thresholds of the gold gratings in the vacuum compressor. The 10-J maximum output energy in a <1-ps-length transform-limited pulse yields peak powers in excess of 10 TW. An ~f/3 off-axis parabolic mirror provides nearly diffraction-limited focusing to ~4-µm (FWHM) spot sizes that yield intensities on target up to 4 × 1019 W/cm2.
A veritable workhorse, the MTW can access experimental regimes beyond those typically reached by conventional tabletop laser systems without requiring the cost and schedule overhead associated with large-scale facilities. The high shot rate and availability of this flexible, experimental platform facilitates parametric studies with the good statistics required to study important physics issues. It also allows novel target experiments to be tested before they are transferred to large-scale lasers like OMEGA EP. Examples of important experimental features conducted by the MTW include:
- high-temporal-contrast laser enhancements and diagnostic development, enabling solid-target experiments
- high pointing stability makes it possible to use small, low-mass targets (Vtarget ≈ 10–6 mm3)
Target-diagnostic development on MTW has included time-integrated Kα photon spectroscopy, high-resolution x-ray crystal imaging, time-resolved x-ray spectroscopy, high-energy ion-emission analysis, and optical-transition-radiation diagnosis. Each diagnostic has been a successful platform for diagnostic development in MTW experiments and for future deployment on OMEGA EP.