Polarization of photon echoes from the [gamma]? band of sulfur hexafluoride /

J. Meckley

William Gutman

By applying a short, intense pulse from a Q-switched carbon dioxide laser to gaseous sulfur hexafluoride, Kumar Patel and Richard Slusher of Bell Telephone Laboratories have made the gas transparent to 10.6-micron radiation (Phys. Rev. Letters 19, 1019, 1967). They have thus verified the self-induced transparency first found with a ruby laser system by Erwin Hahn and Samuel McCall of Berkeley (PHYSICS TODAY, August 1967, page 47). To observe the effect, one must match the exciting frequency to a strongly absorbing transition in the sample.

Igor V. Yevseyev, Valery M. Yermachenko

Wolfgang Riede, Thomas Hall, Hans H. Klingenberg

An investigation was made determining the parameters affecting the phase conjugate reflectivity in a four-wave mixing scheme using a pulsed TEA CO2 laser and gaseous sulfur hexafluoride (SF6) as the nonlinear medium. With a low energy CO2 laser (60 mJ pulse energy) an optimum energy reflectivity of 20 % was achieved at a pump-probe angle of 30 mrad, a SF6 pressure of 50 hPa at the lOiim P(1O) laser transition for exactly aligned counterpropagating pump waves. In addition, the reflectivity showed a substructure when enlarging the angular mismatch between the pump waves. A simulation of the phase conjugate intensity distribution was carried out solving the Kirchhoff- Fresnel integral equation.

W. M. Gutman, C. V. Heer