Measurement of electron and neutral particle densities using a two-color optical fiber interferometer.

A two-color homodyne Mach-Zehnder optical fiber interferometer is developed for the measurement of electron and neutral particle densities in a high-density capsule θ-pinch device. The interferometer leverages the disparate contributions of distinct particles to the refractive index across two discrete wavelengths of 1310 and 1550 nm and incorporates the contributions of both electron and neutral particle densities to the phase shift in the plasma. The temporal evolutions of line-integrated electron and neutral argon densities are successfully measured by the interferometer.