TSD LPI Scientific seminar, 25.04.2023

Speaker: Konstantin Lvovich Gubsky (National Research Nuclear University “MEPhI”; Laboratory of Laser Diagnostics of the Moscow Institute of Laser and Plasma Technologies)
Topic of the report: “Uneven and heterodyne interferometry in physical measurements”

Abstract: Interferometry is an accurate and flexible way to measure various physical quantities and study a wide range of processes. At the same time, interferometers in their traditional two-beam homodyne design are devices that are extremely sensitive to experimental conditions and the influence of external factors. Their accuracy and measurement range are limited both by the correspondence of the optical scheme to the measurements carried out and by the data interpretation algorithms used.

However, almost all problems of interferometry can be solved by complicating optical and/or electronic circuits, switching to quadrature, heterodyne circuits. The report describes the methods of non-shoulder and heterodyne interferometry used by the authors in solving various scientific metrological problems.

The solutions described in the report are given by the example of systems designed for specific practical tasks:

  1. Metrological support of movements in the nanometer range. Three-coordinate interferometers for probe microscopy with geometry measurement accuracy at the level of angstrom units.
  2. Speed measurement in fast-flowing experiments. Interferometric systems with photoregistration and field visualization in experiments on the physics of the extreme state of matter.
  3. Measurement of the electron density of plasma. Multichannel and two-color systems in the study of plasma accelerators and tokamaks.