Measuring near-DC conductivity of laser generated warm dense aluminum using single-shot terahertz spectroscopy*

We present experimental measurements of the near-DC electrical conductivity of laser generated warm dense matter (WDM) measured by single-shot terahertz (THz) time-domain spectroscopy. WDM refers to a state where the temperature is between ~1-100 eV and with density is 0.1-10 times that of a solid [1]. This makes the properties of WDM difficult to model using conventional plasma or condensed matter theories. The DC electrical conductivity of WDM is of particular importance for its applications to fusion science and planterary astrophysics. A promising method to determine the DC conductivity is to use THz spectroscopy. THz pulses can probe properties close to DC because the fields evolve on significantly slower timescales compared to the electron-electron and electron-ion interactions. Recently, we have developed an experimental platform for studying laser heated WDM using single-shot THz time domain spectroscopy [2-3]. Here we present experimental results using single-shot THz transmission of nm-thick aluminum films.

1) A. Ng, et al., Laser Part. Beams 23(4), 527–537 (2005).

2) B. Russell et al., Opt. Expr. 25, 16140 (2017)

3) B. K. Ofori-Okai et al., Accepted in Rev. Sci. Instr.