Commissioning of a frequency-resolved optical gating system at the OMEGA EP laser facility: SpecFROG.

Abstract

We present the design and commissioning of a new single-shot, frequency-resolved optical gating system on the OMEGA EP laser facility - dubbed "SpecFROG" - for characterizing the instantaneous intensity and phase of ∼10 ps pulses used to study ultra-intense laser-plasma interactions. A polarization-gating geometry is employed to ensure tha the diagnostic is broadband and has unambiguous time directionality. SpecFROG is capable of characterizing ∼10 s of mJ pulses with durations between 0.5-25 ps with ≲285 fs geometrical temporal blurring and ∼0.1% spectral shift resolutions over an adjustable total spectral shifting window of ∼15% of the carrier wavelength λo; configurations currently exist for both the fundamental (1ω, λo = 1.054 μm) and second harmonic (2ω, λo = 0.527 μm) of the EP pulse. Initial specular reflectivity measurements of the ∼1 kJ, ∼10 ps OMEGA EP laser off solid density aluminum targets suggest drastically different scalings for specular pulse properties compared to picosecond-scale pulses of comparable intensities.