CONTENTS I. Introduction 637 II. Theory of the Stark Effect 638 1. The Stark Effect in a Constant Electric Field 638 2. The Stark Effect in Alternating Electric Fields 640 III. The Study of the Stark Effect in a Constant Electric Field 643 1. Observation of the Shifts of Centers of Gravity of Absorption Lines in Atomic Beams 643 2. Study of the Stark Effect by Observation of Electric Double Refraction 644 3. Study of the Stark Effect by the Method of Comparison with Hyperfine Splitting 646 4. Observation of the Stark Effect by Radiospectroscopic Methods 646 5. Study of the Stark Effect by the Method of Double Radiooptical Resonance 647 6. Observation of the Stark Effect by Level-crossing and Beat Methods 649 IV. The Study of the Stark Effect in Fields of Optical Frequency 651 1. Observation of Shifts and Splittings of Levels of the Ground State of Hg 199 by Resonance Light 651 2. Observation of Shifts and Splittings of Levels of Potassium Atoms in the Radiation Field of a Ruby Laser 653 V. Conclusion 654 Literature Cited 656
We report observations of an optically produced splitting of the luminescence lines of concentrated ruby samples for optical intensities of approximately 200 W/
cm2. This splitting is attributed to optical generation of a large, uniform electric field (
106 V/cm). At high intensities (
l>2 kW/
cm2) high photoconductivity causes the splitting to decrease and disappear. It is suggested that the field-generation mechanism is directional charge transfer via two-step excitation of
Cr3+ ion or ion clusters. The required electrical asymmetry is shown to be due to a growth-induced anisotropy of the
Cr3+ ion distribution.