Plasma density measurements using THz pulses from laser-plasmas

Abstract

Measurement of the electron density of the inductively-coupled plasma (ICP) was performed by using laser-plasma-produced THz (terahertz) pulses, which are generated by focusing laser beams in gas with DC bias. The generated THz pulses are sent to the ICP and the plasma density is measured by the THz time-domain spectroscopy (THz-TDS) method. By measuring the amount of the phase shift caused by the THz pulse passing through the plasma, the electron density of the plasma can be deduced. The result shows that the ICP device can produce argon plasmas with electron densities in the range of 10