Deep blue microlaser

TLDR: In this article, the authors proposed a blue microlaser, which is a composite cavity formed form a gain medium crystal and a nonlinear frequency doubling material which together have four spaced parallel dielectrically coated faces and which is positioned in close proximity to a diode laser pump source.

Abstract: A monolithic diode pumped solid-state laser (11) comprising as the laser host neodymium-doped yttrium orthovanadate (Nd:YVO4) (12, 52) or neodymium-doped gadolinium orthovanadate (Nd:GdVO4) (57, 67) operating on the 4F3/2 → 4I9/2 (∩914 nm or ∩912 nm respectively) transition, to which a suitable nonlinear optic material (16), such as potassium niobate (KNbO3) or beta barium borate (BBO), is bonded. The nonlinear crystal gives rise to intracavity frequency doubling to ∩457 or ∩456 nm. The microlaser is a composite cavity formed form a gain medium crystal and a nonlinear frequency doubling material which together have four spaced parallel dielectrically coated faces (14, 17, 18, 15) and which is positioned in close proximity to a diode laser pump source (13) for phase-matched harmonic generation of blue light along an axis of propagation which lies substantially perpendicular to the two faces of the composite cavity. By employing specific doping concentration-length products of lasant material and pumping the gain medium which has a specific crystalline orientation the desired efficient blue microlaser is achieved. Alternative embodiments combine the Nd:YVO4 and Nd:GdVO4 elements to enhance certain output characteristics of the laser.