Single-shot optical conductivity measurement of dense aluminum plasmas

Abstract

The optical conductivity of a dense femtosecond laser-heated aluminum plasma heated to 0.1-1.5 eV was measured using frequency-domain interferometry with chirped pulses, permitting simultaneous observation of optical probe reflectivity and probe pulse phase shift. Coupled with published models of bound-electron contributions to the conductivity, these two independent experimental data yielded a direct measurement of both real and imaginary components of the plasma conductivity.

Simplified single-shot supercontinuum spectral interferometry

“…Interfering this probe pulse with a replica reference pulse in an imaging spectrometer yields a 2-dimensional (2D) (1D space and wavelength) interferogram from which the pump-induced phase shift (hence, the ultrafast transient) can be extracted . This technique, and variants [2,3], have been used to measure various phenomena including double-step ionization of helium [4], laser wakefields [5], n 2 measurement of air at mid-and long wave-IR wavelengths [6], bound-electron nonlinearities near the ionization threshold for various gases [7], ultrafast nonlinear electronic, rotational, and vibrational responses in molecular gases [8], optical conductivity of laser-heated aluminum plasma [9], time domain terahertz waveform [10], polymorphic phase transitions in iron [11], and characterize laser-induced shock in materials [12].…”