Kerr combs with selectable central frequency

Abstract

Optical frequency combs produced by femtosecond Ti:sapphire lasers have revolutionized many applications across the fields of science and metrology and have opened new vistas in sensing and spectroscopy¹. An alternative approach based on four-wave mixing in solid-state microresonators (Del'Haye in Nature 450:1214, 2007, Del'Haye et al. in Phys. Rev. Lett. 101:053903, 2008, Savchenkov in Phys. Rev. Lett. 101:093902, 2008, Grudinin et al. in Opt. Lett. 34:878, 2009, Agha et al. in Opt. Express 17:16209, 2009, Levy in Nature Photon. 4:37, 2009, Razzari in Nature Photon. 4:41, 2009, Braje et al. in Phys. Rev. Lett. 102:193902, 2009),10,11,12, (Chembo et al. in Phys. Rev. Lett. 104:103902, 2010) has been developed to create compact, high-repetition-rate, optical-frequency comb (Kerr comb) generators. In this Letter, we show that a comb centred at virtually any frequency within the transparency window of the microresonator host material can be generated by appropriate design of the microresonator shape, which controls the group velocity dispersion. We present a theoretical framework supporting this and demonstrate the first frequency comb centred at 794 nm.