Holography in the IR region of the spectrum, based on scanning image converters

The appearance and vigorous development of continuously acting COa lasers, operating at = 10.6 ~, also caused rapid development of techniques for this range. It became necessary to investigate and control the quality of optical elements of complex systems made of such materials as infrared glasses, Ge, InSb, CdHgTe, etc., which are difficult or impossible to control in the visible and near-IR ranges. Extensive possibilities in the investigation of such materials are opened up by methods of IR holography, in particular, holographic inter~ ferometry. This part of the spectrum is also of considerable interest to specialists con~ cerned with laser methods for investigating plasma, since the sensitivity of interference measurements of electron concentration increases with the wavelength of the probing radiation. In particular, when an infrared C02 laser radiating at % = 10,6 ~ is used in interferometric investigations, the minimum observable electron concentration is about 1/15 of the value found when a ruby laser is used [i].