Abstract
The state of the art in electro-optics has advanced to the point where digital holographic acquisition
of wavefronts is now possible. Holographic wavefront acquisition provides the phase of the
wavefront at every measurement point. This can be done with accuracy on the order of a thousandth
of a wavelength, given that there is sufficient care in the design of the system. At wave frequencies
which are much greater than the plasma frequency, the plasma index of refraction is linearly
proportional to the electron density and wavelength, and the measurement of the phase of a
wavefront passing through the plasma gives the chord-integrated density directly for all points
measured on the wavefront. High-speed infrared cameras up to 40 000 fps at 644 pixels
with resolutions up to 640512 pixels suitable for use with a CO2 laser are readily available, if
expensive.
