Heterodyne CO2-laser interferometer with direct phase read-out

C A Hugenholtz; B J Meddens

doi:10.1063/1.1135997

Heterodyne CO2-laser interferometer with direct phase read-out

Rev Sci Instrum. 1979 Sep;50(9):1123-4. doi: 10.1063/1.1135997.

Authors

C A Hugenholtz¹, B J Meddens

Affiliation

¹ Association Euratom-FOM, FOM-Instituut voor Plasmafysica, Rijnhuizen, Nieuwegein, The Netherlands.

PMID: 18699681
DOI: 10.1063/1.1135997

Abstract

A CO2-laser interferometer with heterodyne detection has been built to measure electron line densities of plasmas in the range of 10(18) to 5 x 10(22) m(-2). Heterodyne operation is accomplished by using two counteracting acousto-optic modulators at a difference frequency of 500 kHz. A digital phase comparator is used to obtain direct read-out of the phase shift. The time resolution is 3.5 micros.