The 77th JSAP Autumn Meeting, 2016

Presentation information

Oral presentation

4 JSAP-OSA Joint Symposia 2016 » 4.5 Information Photonics

[14a-C301-1~9] 4.5 Information Photonics

Wed. Sep 14, 2016 9:00 AM - 12:15 PM C301 (Nikko Tsuru)

Ryoichi Horisaki(Osaka Univ.), Hirotsugu Yamamoto(Utsunomiya Univ.), Norimichi Tsumura(Chiba Univ.)

10:00 AM - 10:15 AM

[14a-C301-4] Dual-wavelength digital holography using optical frequency synthesizer

〇(M2)Clement Trovato1,2,3, Dahi Ghareab Abdelsalam1,3, Takayuki Ogawa1,3, Takeo Minamikawa1,3, Hirotsugu Yamamoto3,4, Emmanuel Abraham2,5, Takeshi Yasui1,3 (1.Tokushima Univ., Japan, 2.Bordeaux Univ., France, 3.JST, ERATO MINOSHIMA IOS, 4.Utsunomiya Univ., 5.LOMA)

Keywords:Digital Holography, Optical frequency synthesizer

Digital holography (DH) has become a topic of growing interest which finds its spot in the three dimensional imaging, as well as biomedical imaging and metrology. One practical limitation in DH with a single wavelength light is that it can only handle smooth profiles and step height less than half a wavelength (lambda/2). To extend the dynamic range in depth over lambda/2, dual-wavelength DH has been proposed. In this method, DH is performed at two different wavelengths (lambda1, lambda2), and then the synthesized wavelength between them lambda1,2 [= ( lambda1.lambda2) /| lambda1-lambda2|] is used to extend the dynamic range in depth up to lambda1,2. However, since stable CW laser oscillates at only a few discrete wavelengths, such as 532 nm, 633 nm, or 780 nm, it is difficult to obtain an arbitrary lambda1,2. Recently, optical frequency comb (OFC) has emerged as a new technique for optical frequency metrology. OFC can be used as an optical frequency ruler by phase-locking a carrier-envelope-offset frequency fceo and a repetition frequency frep to a frequency standard. One interesting application of OFC is an optical frequency synthesizer (OFS), which is a single-mode CW laser phased locked to one optical frequency mode of OFC. Furthermore, continuous tuning can be achieved by changing frep while keeping the phase-locking of CW laser to OFC. Such characteristics of OFS are attractive for dual-wavelength DH because lambda1,2 can be arbitrarily generated from µm order to mm order over m order depending on the sample. We demonstrated dual-wavelength DH using OFS.