Accession Number:

ADA071284

Title:

Interference Pulses in Optical Free Induction Decay,

Descriptive Note:

Corporate Author:

IBM RESEARCH LAB SAN JOSE CALIF

Report Date:

1974-08-16

Pagination or Media Count:

27.0

Abstract:

A new feature of optical free induction decay FID is observed in a coherently prepared sample of 13CH3F by the method of Stark switching. The preparative phase is due to the resonant steady state excitation by a cw laser beam and is followed by FID upon sudden application of a d.c. Stark field that switches the molecular sample out of resonance. The emission is not observed as a simple decay but instead appears as a train of sharp pulses regularly spaced in time due to a repetitive interference. This situation arises because an entire set of infrared transitions within the Stark split manifold are initially prepared, in contrast to our previous study of a nondegenerate transition. The emission, which beats with the laser, produces a heterodyne beat spectrum consisting of a set of regularly spaced frequencies that is the Fourier transform of the slowly decaying pulse progression observed. We thus demonstrate what is the optical analog of the well known NMR method of high resolution pulse Fourier spectroscopy. The detailed behavior of the pulse train agrees well with a FID theory that assumes the transitions to be uncoupled. The subtle behavior of FID near the time origin is explored also by approximate analytic expressions that reveal a near zero or a sizable amplitude depending on the degree of saturation in the preparative stage.

Subject Categories:

  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE