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Terahertz wavefront assessment based on 2D electro-optic imaging

hal.structure.identifierTokushima University
dc.contributor.authorCAHYADI, H.
hal.structure.identifierTokushima University
dc.contributor.authorICHIKAWA, R.
hal.structure.identifierLaboratoire Ondes et Matière d'Aquitaine [LOMA]
dc.contributor.authorDEGERT, J.
hal.structure.identifierLaboratoire Ondes et Matière d'Aquitaine [LOMA]
dc.contributor.authorFREYSZ, E.
hal.structure.identifierTokushima University
dc.contributor.authorYASUI, T.
hal.structure.identifierLaboratoire Ondes et Matière d'Aquitaine [LOMA]
dc.contributor.authorABRAHAM, Emmanuel
dc.date.issued2015-03-14
dc.date.conference2015-03-14
dc.description.abstractEnComplete characterization of terahertz (THz) radiation becomes an interesting yet challenging study for many years. In visible optical region, the wavefront assessment has been proved as a powerful tool for the beam profiling and characterization, which consequently requires 2-dimension (2D) single-shot acquisition of the beam cross-section to provide the spatial profile in time- and frequency-domain. In THz region, the main problem is the lack of effective THz cameras to satisfy this need. In this communication, we propose a simple setup based on free-space collinear 2D electrooptic sampling in a ZnTe crystal for the characterization of THz wavefronts.In principle, we map the optically converted, time-resolved data of the THz pulse by changing the time delay between the probe pulse and the generated THz pulse. The temporal waveforms from different lens-ZnTe distances can clearly indicate the evolution of THz beam as it is converged, focused, or diverged. From the Fourier transform of the temporal waveforms, we can obtain the spectral profile of a broadband THz wave, which in this case within the 0.1-2 THz range. The spectral profile also provides the frequency dependency of the THz pulse amplitude. The comparison between experimental and theoretical results at certain frequencies (here we choose 0.285 and 1.035 THz) is in a good agreement suggesting that our system is capable of THz wavefront characterization. Furthermore, the implementation of Hartmann/Shack-Hartmann sensor principle enables the reconstruction of THz wavefront. We demonstrate the reconstruction of THz wavefronts which are changed from planar wave to spherical one due to the insertion of convex THz lens in the THz beam path. We apply and compare two different reconstruction methods: linear integration and Zernike polynomial. Roughly we conclude that the Zernike method provide smoother wavefront shape that can be elaborated later into quantitative-qualitative analysis about the wavefront distortion.
dc.language.isoen
dc.subject.enTerahertz radiation
dc.subject.enWavefront
dc.subject.enSensors
dc.subject.enSpherical lenses
dc.subject.enCameras
dc.subject.enCrystals
dc.subject.enElectro optics
dc.title.enTerahertz wavefront assessment based on 2D electro-optic imaging
dc.typeCommunication dans un congrès avec actes
dc.identifier.doi10.1117/12.2078450
dc.subject.halPhysique [physics]
bordeaux.page6
bordeaux.volume9362
bordeaux.countryUS
bordeaux.title.proceedingProc. SPIE 9362, Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications VIII
bordeaux.conference.citySan Francisco, California
bordeaux.peerReviewednon
hal.identifierhal-01555988
hal.version1
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-01555988v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.date=2015-03-14&rft.volume=9362&rft.spage=6&rft.epage=6&rft.au=CAHYADI,%20H.&ICHIKAWA,%20R.&DEGERT,%20J.&FREYSZ,%20E.&YASUI,%20T.&rft.genre=proceeding


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