Kilometer-path low-temperature multiple-reflection cell for laser spectroscopy using tunable semiconductor diodes

Variable-temperature 3-m absorption cell developed for spectroscopic measurements of gases

A variable-temperature absorption cell 3 m in length, which was designed and built for spectroscopic measurements of gases in combination with a Bruker IPS 120 HR interferometer, is described. The cell is surrounded by a cooling system and a heating system. The heating system consists of a computer-controlled set of 16 independent heating elements distributed over the length of the cell. The entire assembly enables measurements to be made in the temperature range from 123 to 423 K. The temperature of the cell can be stabilized within ±0.5 K over the entire length in this temperature range. The performance of the cell is discussed in relation to a spectroscopic temperature determination by the use of CO(2) intensity measurements.

Optical multipass matrix systems

Large relative aperture three- and four-objective multipass matrix systems ensuring the longest optical path length in an absorbing medium have been developed for high resolution laser spectroscopy. In these systems the images are formed on the field mirrors as compact rectangular matrices with a controlled amount of lines and columns. The number of passes may reach 500 for mirrors with high reflectivity layers. Having a simple construction, the matrix systems provide high optical and operational features. In view of their capacities the matrix systems are new generation multipass systems.