Multipass reconfiguration of the HELEN Nd:glass laser at the Atomic Weapons Establishment

Abstract

The HELEN high-power Nd:glass laser has been rebuilt in a new multipass configuration that requires fewer components to maintain existing performance. This is expected to lead to greater system availability and reduced running costs. We describe the new design, discuss some of the key issues that had to be addressed, and present operational results.

Role of hydrodynamics simulations in laser-plasma interaction predictive capability

“…Experiments were conducted at the HELEN laser facility [14] to study the propagation of a 2ω laser beam. These experiments have been described in greater detail in previous papers [10,15].…”

The application of laser-driven proton beams to the radiography of intense laser–hohlraum interactions

“…The experimental campaign, carried out at the Helen facility [17] in AWE, adopted the setup sketched in figure 2. The experiment employed two different laser beams.…”

Hundred-Joule-level, nanosecond-pulse Nd:glass laser system with high spatiotemporal beam quality

“…Among the preamplifier systems, many of these mediumscale lasers use single-pass or multi-pass amplifier structure except Helen facility, where a regenerative amplifier structure is adopted [31] . To our knowledge, the regenerative amplifier is widely used in large high-power laser systems [37][38][39][40] because of its significant reductions in both initial construction costs and subsequent operation costs as a result of a decrease in the number of components for a given output energy.…”

“…In these medium-scale laser systems, spatial beam-shaping methods generating flat-top fluence distributions in the output near field have been investigated, such as image relaying with spatial filtering [23][24][25][26][27][28][31][32][33] , stimulated Brillouin scattering phase conjugation mirrors (SBS-PCMs) [27] , Gaussian mirror output coupler in the oscillator [25] , circular aperture selecting the quasi-uniform intensity region at the center of the expanded beam [31] and diffractive optical element (DOE) [26] . However, these are all passive shaping methods used for particular laser system, which is not suitable for achieving high spatial beam quality in complex high-power lasers applied in accurate physics experiments.…”