Colloquium
Department of Physics, NCU
Optical frequency combs at LNE-SYRTE : some novel applications in optical frequency metrology
Date 2015.01.07(三)
Time 13:30
Place S4-625
Speaker
Dr. Yann LE Coq
SYRTE, Optical Frequency Group
(巴黎天文台，國家時空標準研究所，光頻研究群)
Abstract (附，鄭王曜老師的簡單翻譯，電梯一分鐘懶人包)
光梳雷射是目前光頻計量的利器，連結了微波標準(1010 Hz)到光頻率標準 (1015 Hz)。我的演講將描述法國國家時空標準研究所的貢獻，尤其在光纖光梳雷射這一塊，很可能在科學上，甚至軍事上，會有重要的應用，同時也會提到我們在Nature Photonics 2014文章上的創意 (三千億年誤差一秒)，為目前世界上光梳工藝的極致。
“Optical frequency combs are nowadays the instrument of choice for optical frequency metrology worldwide, as they provide a phase coherent bridge between different optical frequencies, as well as between the optical and radio-frequency/microwave domain.
I will be describing a few novel applications that go beyond the simple measurement of optical frequency that have been developed at LNE-SYRTE (the National Metrology Institute of France for time and frequency) over the past few years. In particular, I will describe our work toward realizing and characterizing fiber-based optical frequency combs in the ultra-narrow linewidth regime.
I will also describe the application of low phase-noise microwave generation with these tools. As a matter of facts, optical frequency combs are now capable of producing the lowest phase-noise microwave source of every competing technology in a large range of Fourier frequencies, which may have a strong impact for scientific, civil and military applications alike.
To finish, I will describe our latest experiments which demonstrated the transfer of spectral purity between different optical wavelengths at the 10-18 level (Nature Photonics 8, 219, 2014). This demonstration is an important milestone for the future development of ultra-stable cw lasers for optical frequency metrology, as it allows sharing a single laser in between many different experiments operation at various wavelengths, thanks to the use of a state-of-the-art frequency comb”.
鄭王曜老師的說明：
法國科學家把光梳雷射在計量學上應用到極致，並登在2014年nature photonics上，這個演講很適合同學們了解普物課本第一頁，時間標準，人類所到達的境界目前在哪裡。(修光學的同學，請讓助教知道你聽了演講)
補充： 古老國家的時間標準，是由國家天文台負責。加上愛因斯坦告訴我們時空是不需要區分的，因此空間也可由時間定義。 所以很多國家space-time標準由天文台負責。巴黎，也是聯合國底下，許多度量衡標準的中心。