Application of dye lasers to probe the upper atmosphere by resonance scattering

A dye laser, tuned to one of the sodium D lines, has been used to measure atomic sodium which occurs in the atmosphere at a height of about 90 km. Details of the laser, tuning arrangements and other equipment are given, and the principle of the measurement and method of calibration are described. The results obtained and their relevance to atmospheric theory are indicated. The possibility of measuring other atmospheric constituents by the same technique is considered, and the laser requirements are indicated.