Abstract

Metastable helium atoms, because of their relatively simple energy-level structure, low mass, and inert quality, have found widespread applications in many areas of atomic physics. Many of these experiments require a source of narrow-linewidth radiation resonant with the 2³S-to-2³P transition at 1.083 μm. The most efficient source of 1.083-μm radiation is the LNA laser.¹ LNA can be efficiently pumped by GaAs diode lasers; however, simple standing-wave cavities produce a relatively low single-frequency output because of competition between intracavity frequency-selective elements and spatial hole burning.² In this paper we discuss a technique to considerably increase the single-frequency output power by eliminating spatial hole burning through the use of a polarization-gradient light field (or twisted-mode) inside the laser crystal.³ Previously this technique has been successfully applied to diode-pumped Nd:YAG lasers.⁴

© 1993 Optical Society of America