Recording electric field evolution in single-shot with THz bandwidth is needed in science including spectroscopy,plasmas,biology,chemistry,Free-Electron Lasers,accelerators,and material inspection.However,the potential application range depends on the possibility to achieve sub-picosecond resolution over a long time window,which is a largely open problem for single-shot techniques.To solve this problem,we present a new conceptual approach for the so-called spectral decoding technique,where a chirped laser pulse interacts with a THz signal in a Pockels crystal,and is analyzed using a grating optical spectrum analyzer.By borrowing mathematical concepts from photonic time stretch theory and radio-frequency communication,we deduce a novel dual-output electro-optic sampling system,for which the input THz signal can be numerically retrieved—with unprecedented resolution—using the so-called phase diversity technique.We show numerically and experimentally that this approach enables the recording of THz waveforms in single-shot over much longer durations and/or higher bandwidth than previous spectral decoding techniques.We present and test the proposed DEOS (Diversity Electro-Optic Sampling) design for recording 1.5 THz bandwidth THz pulses,over 20 ps duration,in single-shot.Then we demonstrate the potential of DEOS in accelerator physics by recording,in two successive shots,the shape of 200 fs RMS relativistic electron bunches at European X-FEL,over 10 ps recording windows.The designs presented here can be used directly for accelerator diagnostics,characterization of THz sources,and single-shot Time-Domain Spectroscopy.

Eléonore Roussel;Christophe Szwaj;Clément Evain;Bernd Steffen;Christopher Gerth;Bahram Jalali;Serge Bielawski

Univ.Lille,CNRS,UMR 8523-PhLAM-Physique des Lasers,Atomes et Molécules,Centre d'(E)tude Recherches et Applications (CERLA),F-59000 Lille,France;DESY (Deutsches Elektronen-Synchrotron),Notkestr.85,D-22607 Hamburg,Germany;Electrical and Computer Engineering Department,University of California,Los Angeles,420 Westwood Plaza,90095 Los Angeles,CA.USA

光：科学与应用（英文版）

[1]Eléonore Roussel;Christophe Szwaj;Clément Evain;Bernd Steffen;Christopher Gerth;Bahram Jalali;Serge Bielawski-.Phase Diversity Electro-optic Sampling:A new approach to single-shot terahertz waveform recording)[J].光：科学与应用（英文版）,2022(01):87-100

Lasers,DEOS

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