Frequency combs

Definition

Frequency combs are light sources with a spectrum that comprises a series of sharp, equally spaced lines. The frequencies of these lines are known to a very high degree of accuracy, which makes frequency combs an important tool in optical metrology and high-resolution spectroscopy.

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Latest Research and Reviews

  • Research | | open

    Chip-based microresonator frequency combs are currently limited to the infrared spectral region. Here, the authors generate combs whose center frequency approaches the visible spectrum enabled by combining geometrical and mode-hybridization dispersion control in silica microresonators.

    • Seung Hoon Lee
    • , Dong Yoon Oh
    • , Qi-Fan Yang
    • , Boqiang Shen
    • , Heming Wang
    • , Ki Youl Yang
    • , Yu-Hung Lai
    • , Xu Yi
    • , Xinbai Li
    •  & Kerry Vahala
  • Research |

    Self-starting harmonic frequency comb generation with a THz repetition rate in a quantum cascade laser is demonstrated. The mode spacing uniformity is verified to within 5 × 10−12 parts of the central frequency. The findings extend the range of applications of quantum cascade laser frequency combs.

    • Dmitry Kazakov
    • , Marco Piccardo
    • , Yongrui Wang
    • , Paul Chevalier
    • , Tobias S. Mansuripur
    • , Feng Xie
    • , Chung-en Zah
    • , Kevin Lascola
    • , Alexey Belyanin
    •  & Federico Capasso
  • Research |

    The observation of soliton crystals in monolithic Kerr microresonators is reported. The physics of such resonators is explored in a regime of dense soliton occupation, offering a way to increase the efficiency of Kerr combs.

    • Daniel C. Cole
    • , Erin S. Lamb
    • , Pascal Del’Haye
    • , Scott A. Diddams
    •  & Scott B. Papp
    Nature Photonics 11, 671–676
  • Research | | open

    Spectroscopic ellipsometry is an established technique to characterize the optical properties of a material. Here, Minamikawa et al. combine the method with dual-comb spectroscopy, which allows them to obtain ellipsometric parameters including the phase difference between s-polarized and p-polarized light.

    • Takeo Minamikawa
    • , Yi-Da Hsieh
    • , Kyuki Shibuya
    • , Eiji Hase
    • , Yoshiki Kaneoka
    • , Sho Okubo
    • , Hajime Inaba
    • , Yasuhiro Mizutani
    • , Hirotsugu Yamamoto
    • , Tetsuo Iwata
    •  & Takeshi Yasui

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