Sodium Resonance Fluorescence System

Transmitter

The sodium system is used to determine the temperature in the mesosphere and the lower thermosphere through the measurements of the line shape of the sodium D2 line.

A 6-W argon ion laser used to pump up the lasing medium in a ring-dye laser and in a custom-pulse dye amplifier (transmitter schematic). A Na vapour cell generates a feedback for an electronic system that scans the ring-dye laser (ring schematic) over the Na fine structure doublet. An injection-seeded 12W Nd:YAG laser is used to amplify the ring dye light.

Sodium system data

• [Fig.1] Doppler free saturation spectroscopy.
• [Fig.2] Effect of convolving Na backscatter profile with laser beam having a gaussian profile width 130 MHz rms.
• [Fig.3] Variation of sodium D2 cross-section with temperature.
• [Fig.4] Relative intensity as a function of frequency interval. Model and observation data.