title: Diffraction-limited ultrabroadband terahertz spectroscopy.
abstract: Diffraction is the ultimate limit at which details of objects can be resolved in conventional optical spectroscopy and imaging systems. In the THz spectral range, spectroscopy systems increasingly rely on ultra-broadband radiation (extending over more 5 octaves) making a great challenge to reach resolution limited by diffraction. Here, we propose an original easy-to-implement wavefront manipulation concept to achieve ultrabroadband THz spectroscopy system with diffraction-limited resolution. Applying this concept to a large-area photoconductive emitter, we demonstrate diffraction-limited ultra-broadband spectroscopy system up to 14.5 THz with a dynamic range of 10(3). The strong focusing of ultrabroadband THz radiation provided by our approach is essential for investigating single micrometer-scale objects such as graphene flakes or living cells, and besides for achieving intense ultra-broadband THz electric fields.
authors.affiliation: Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France.
authors.forename: M
authors.initials: M
authors.lastname: Baillergeau
authors.affiliation: Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France.
authors.forename: K
authors.initials: K
authors.lastname: Maussang
authors.affiliation: Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France.
authors.forename: T
authors.initials: T
authors.lastname: Nirrengarten
authors.affiliation: Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France.
authors.forename: J
authors.initials: J
authors.lastname: Palomo
authors.affiliation: School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS29JT, UK.
authors.forename: L H
authors.initials: LH
authors.lastname: Li
authors.affiliation: School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS29JT, UK.
authors.forename: E H
authors.initials: EH
authors.lastname: Linfield
authors.affiliation: School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS29JT, UK.
authors.forename: A G
authors.initials: AG
authors.lastname: Davies
authors.affiliation: Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France.
authors.forename: S
authors.initials: S
authors.lastname: Dhillon
authors.affiliation: Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France.
authors.forename: J
authors.initials: J
authors.lastname: Tignon
authors.affiliation: Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France.
authors.forename: J
authors.initials: J
authors.lastname: Mangeney