Effect of Laser Wavelength and Pulse Duration on Laser-Light Absorption and Back Reflection

Absorption efficiency has been measured in laser-irradiated plane-target experiments with various laser wavelengths (1.06, 0.53, and 0.26 μm), pulse durations (100 ps, 2 ns), and intensities (${10}^{10}$-2×${10}^{15}$ W/cm). Results show a strong increase of absorption for long pulses, low intensities, and short wavelengths which favor inverse bremsstrahlung absorption. A one-dimensional Lagrangian hydrocode (film) is used to interpret these results.