Abstract
Holography1 has always held special appeal as it is able to record and display spatial information in three dimensions2–10. Here we show how to augment the capabilities of digital holography11,12 by using a large number of narrow laser lines at precisely defined optical frequencies simultaneously. Using an interferometer based on two frequency combs13–15 of slightly different repetition frequencies and a lensless camera sensor, we record time-varying spatial interference patterns that generate spectral hypercubes of complex holograms, revealing the amplitudes and phases of scattered wave-fields for each comb line frequency. Advancing beyond multicolour holography and low-coherence holography (including with a frequency comb16), the synergy of broad spectral bandwidth and high temporal coherence in dual-comb holography opens up novel optical diagnostics, such as precise dimensional metrology over large distances without interferometric phase ambiguity, or hyperspectral three-dimensional imaging with high spectral resolving power, as we demonstrate with molecule-selective imaging of an absorbing gas.
Highlights
Holography[1] has always held special appeal as it is able to record and display spatial information in three dimensions[2–10]
With a set-up that involves merely the same simple hardware as that harnessed for dual-comb hyperspectral imaging17–20—two frequency-comb generators and a detector matrix—we take a new route to lensless scan-free three-dimensional (3D) profiling, suited to dimensional metrology of macroscopic and microscopic objects and to advanced optical sensing that combines spatial and spectral information
Even with an inline configuration, the holographic signal is spectrally separated from the non-interferometric zeroth-order signal and those of the twin holograms because it is mapped in a different frequency range
Summary
Holography[1] has always held special appeal as it is able to record and display spatial information in three dimensions[2–10]. We generated two frequency combs of slightly different repetition frequencies, frep for the object comb and frep + δfrep for the reference comb, by dividing the output of a continuous-wave laser with a beam splitter, and sending each beam through an electro-optic amplitude modulator producing pulses of about 50 ps.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
