| Autor: |
Bianchi V; NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa I-56127, Italy., Carey T; Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK., Viti L; NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa I-56127, Italy., Li L; School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK., Linfield EH; School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK., Davies AG; School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK., Tredicucci A; Dipartimento di Fisica, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy., Yoon D; Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK., Karagiannidis PG; Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK., Lombardi L; Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK., Tomarchio F; Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK., Ferrari AC; Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK., Torrisi F; Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK., Vitiello MS; NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa I-56127, Italy. |
| Abstrakt: |
Saturable absorbers (SA) operating at terahertz (THz) frequencies can open new frontiers in the development of passively mode-locked THz micro-sources. Here we report the fabrication of THz SAs by transfer coating and inkjet printing single and few-layer graphene films prepared by liquid phase exfoliation of graphite. Open-aperture z-scan measurements with a 3.5 THz quantum cascade laser show a transparency modulation ∼80%, almost one order of magnitude larger than that reported to date at THz frequencies. Fourier-transform infrared spectroscopy provides evidence of intraband-controlled absorption bleaching. These results pave the way to the integration of graphene-based SA with electrically pumped THz semiconductor micro-sources, with prospects for applications where excitation of specific transitions on short time scales is essential, such as time-of-flight tomography, coherent manipulation of quantum systems, time-resolved spectroscopy of gases, complex molecules and cold samples and ultra-high speed communications, providing unprecedented compactness and resolution. |
