Abstract

Neodymium solid state lasers have been known since the early days of laser development and still provide stable, continuous sources for metrology, quantum optics, high field studies and industrial applications. Most Nd lasers operate in the infrared, emitting from a relatively low energy state that is easily excited by flashlamps or diodes. Operation at shorter wavelengths from the long- lived and high-lying ²F levels located above 38,000 cm⁻¹ has never been reported, because of the difficulty of pumping such levels. However inversion of these levels potentially opens up the possibility of new visible and ultraviolet sources based on Nd³⁺. Here we report continuous-wave (cw) laser action near 403 nm from the ²F_5/2 upper level of pyrolyzed Nd³⁺:δ-Al₂O₃ for the first time. Key aspects of our results are the use of electrical pumping to achieve laser action in a dielectric host, and cw operation without any external feedback structure.

© 2002 Optical Society of America