Two-wavelength holographic interferometry of exploding wires

A pulsed ruby laser, equipped with a frequency-doubling crystal, has been used to make two-wavelength holographic interferograms of exploding-wire events. For selected times after initiation, estimates of electron density have been made by noting the dependence of the phase index of refraction on wavelength. Once the electron contribution to refractivity is known, the heavy-particle contribution to refractivity can be isolated. With an estimate of specific refractivity from oscillator strengths, the concentration of heavier particles has been calculated.