Interaction of two laser fields with a three-level molecular system

Author

Panock, Richard L. ; Temkin, R.J.

Author_Institution

Massachusetts Institute of Technology, Cambridge, MA

Volume

13

Issue

6

fYear

1977

fDate

6/1/1977 12:00:00 AM

Firstpage

425

Lastpage

434

Abstract

The rate of absorption and emission of radiation is calculated for two laser fields interacting with a homogeneously broadened, three-level molecular system. The time-dependent Schrödinger equation is used in the density matrix formalism and the laser fields are treated classically. The laser fields, at frequencies ωpand ωs, are off resonance by δpand δs, respectively, such that $|\\delta _{p}|, |\\delta _{s}| \\ll \\omega _{p}, \\omega _{s}$ . Analytic expressions are derived for the imaginary part of the electric susceptibility, $\\chi$ and $\\chi$ . The present work differs from previous calculations in that the laser fields may have arbitrary values of field strength and each field may be on or off resonance. A discussion is presented of the properties of the solutions for $\\chi$ and $\\chi$ , for both strong and weak laser fields, based on computer evaluation of the general analytic expressions. It is shown that the solutions may be divided into single-photon and two-photon, or Raman, contributions. Conditions for optimizing $dI(\\omega _{s})/dz$ and the photon conversion efficiency are derived. These results may be applied to analyzing the pulsed, optically pumped submillimeter laser and to studying two-photon absorption in a gas.

Keywords

Absorption; Equations; Frequency; Gas lasers; Image analysis; Laser excitation; Optical pulses; Optical pumping; Pump lasers; Resonance;

fLanguage

English

Journal_Title

Quantum Electronics, IEEE Journal of

Publisher

ieee

ISSN

0018-9197

Type

jour

DOI

10.1109/JQE.1977.1069354

Filename

1069354