title: Continuous-wave ultraviolet emission through fourth-harmonic generation in a whispering-gallery resonator.
abstract: We experimentally demonstrate continuous-wave ultraviolet emission through forth-harmonic generation in a millimeter-scale lithium niobate whispering-gallery resonator pumped with a telecommunication-compatible infrared source. The whispering-gallery resonator provides four spectral lines at ultraviolet, visible, near-infrared and infrared, which are equally spaced in frequency via the cascaded-harmonic process and span a 2-octave frequency band. Our technique relies on a variable crystal poling and high transverse order of the modes for phase-matching and a resonator quality factor of over 10(7) to allow cascaded-harmonic generation up to the fourth-harmonic at input pump powers as low as 200 mW. The compact size of the whispering gallery resonator pumped at telecommunication-compatible infrared wavelengths and the low pump power requirement make our device a promising ultraviolet light source for information storage, microscopy, and chemical analysis.
authors: Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, 1301 Beal Ave, Ann Arbor, Michigan 48109, USA.
authors: Jeremy
authors: J
authors: Moore
authors: Matthew
authors: M
authors: Tomes
authors: Tal
authors: T
authors: Carmon
authors: Mona
authors: M
authors: Jarrahi
mesh_terms: D000669:Amplifiers, Electronic; D004867:Equipment Design; D019544:Equipment Failure Analysis; D053844:Lasers, Solid-State; D008029:Lighting / Q000295:instrumentation*; D014159:Transducers; D014466:Ultraviolet Rays