Sub-Doppler submillimeter spectroscopy using molecular beams (A)

The use of corner‐cube mounted Schottky diodes to generate tunable submillimeter laser sidebands, which have a linewidth less than 10 kHz, has recently been reported. In order to demonstrate the ultrahigh resolution of the sideband generation technique, rotational transitions with sub‐Doppler linewidths have been observed in molecular beams formed by capillary arrays.