Lawrence Livermore National Laboratory

Resonance-Transition Alkali Laser
The first demonstration of a resonance-transition alkali laser using Rb vapor occurred at LLNL in the winter of 2002.

Since the advent of lasers more than four decades ago, solid-state and gas lasers have followed largely divergent development paths. Gas lasers are based primarily on direct electrical discharge for pumping (energizing), while solid-state lasers are pumped by flashlamps and semiconductor diode laser arrays.

The alkali-vapor laser's intrinsically high efficiency and its compatibility with today's commercially available diode arrays enable fast-track development paths to tactical systems, with mass-to-power ratios that far exceed what is possible with today's other laser systems.

Building on alkali-vapor laser research done by Z. Konefal, PS&A's Directed Energy Systems and Technology (DEST) program element recently developed a new class of laser that combines features of both gas and solid-state lasers, based on diode excitation of atomic alkali vapors. The defining features of the diode-pumped alkali laser (DPAL) are its ability to be incoherently pumped and its compatibility with diode arrays having several-nanometer-wide spectral emissions. These characteristics distinguish DPALs from previous demonstrations of alkali-based lasers that used narrow-band, coherent pumping to demonstrate lasing.

DEST's extensive laser modeling capability, anchored to experimental laboratory demonstrations, supports extreme power scaling with good efficiency and beam quality.

DEST is the world leader in the development of this new class of laser; the first demonstration took place at Lawrence Livermore National Laboratory in 2002, and it has been followed by many other demonstrations and developments.