Abstract

The experiments described here were done on the ${\text{A}}_2^1\text{P}$ (33) line of sf ₆which lies 6.70 MHz above the center of the P(18) line of the CO₂laser at 10.6 µm.^[1]sf ₆was contained in a 5.6m long cell with NaCl windows. Different from the usual saturated absorption technique, where the pump beam is chopped, phase sensitive detection here was done with a mechanical chopper (750KHz) interrupting the probe beam. Thus all probe transmission is registered irrespective of the laser frequency. It is only because of the high absorption of the cell that high contrast signal can be obtained. In this case the pump laser had 1.0 W power while the probe had 10 mW and both had a 15 mm diameter beam.

© 1992 IQEC