title: Low-power continuous-wave generation of visible harmonics in silicon photonic crystal nanocavities.
abstract: We present the first demonstration of frequency conversion by simultaneous second- and third-harmonic generation in a silicon photonic crystal nanocavity using continuous-wave optical excitation. We observe a bright dual wavelength emission in the blue/green (450-525 nm) and red (675-790 nm) visible windows with pump powers as low as few microwatts in the telecom bands, with conversion efficiencies of ∼ 10 (-5) /W and ∼ 10/ W(2) for the second- and third-harmonic, respectively. Scaling behaviors as a function of pump power and cavity quality-factor are demonstrated for both second- and third order processes. Successful comparison of measured and calculated emission patterns indicates that third-harmonic is a bulk effect while second-harmonic is a surface-related effect at the sidewall holes boundaries. Our results are promising for obtaining practical low-power, continuous-wave and widely tunable multiple harmonic generation on a silicon chip.
authors.affiliation: Dipartimento di Fisica A Volta, Universit`a degli Studi di Pavia, 27100 Pavia, Italy. matteo.galli@unipv.it
authors.forename: Matteo
authors.initials: M
authors.lastname: Galli
authors.forename: Dario
authors.initials: D
authors.lastname: Gerace
authors.forename: Karl
authors.initials: K
authors.lastname: Welna
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Krauss
authors.forename: Liam
authors.initials: L
authors.lastname: O'Faolain
authors.forename: Giorgio
authors.initials: G
authors.lastname: Guizzetti
authors.forename: Lucio Claudio
authors.initials: LC
authors.lastname: Andreani
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D053844:Lasers, Solid-State; D008029:Lighting / Q000295:instrumentation*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation*; D012031:Refractometry / Q000295:instrumentation*; D012825:Silicon / Q000737:chemistry*
chemical_list: D012825:Silicon