Violet cw neodymium upconversion laser

TLDR

The Nd:LaF₃ laser was pumped by simultaneous 788 nm and 591 nm continuous‑wave dye lasers, producing stepwise upconversion excitation of Nd³⁺. The device achieved continuous‑wave lasing at 380 nm, delivering a single‑mode output of 12 mW at 20 K (4 mW at 77 K), and also demonstrated lasing with a single 578 nm pump via sequential absorption.

Abstract

We have observed cw laser action on a new transition (4D3/2→4I11/2) of the Nd3+ ion at 380 nm. This was demonstrated in Nd:LaF3 using an upconversion pumping scheme in which near infrared (788 nm) and visible (591 nm) pump photons from cw dye lasers produce stepwise excitation of the Nd3+ ion. In addition, lasing was observed with a single pump source at wavelengths around 578 nm using doubly resonant, sequential absorption of two yellow photons. Single-mode, cw operation with an output power of 12 mW was measured at 20 K with 1% output coupling and pump powers of several hundred mW. At 77 K the maximum power dropped to 4 mW.