Long-range guided THz radiation by thin layers of water

Abstract

Sczech, R.; Gómez Rivas, J.; Berrier, A.; Giannini, V.; Pirruccio, G.; Debus, C.; Schäfer-Eberwein, H.; Haring Bolivar, P. Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publicationCitation for published version (APA): Sczech, R., Gómez Rivas, J., Berrier, A., Giannini, V., Pirruccio, G., Debus, C., ... Haring Bolivar, P. (2012). Long-range guided THz radiation by thin layers of water. Optics Express, 20(25), 27781-27791. DOI: 10.1364/OE.20.027781 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Abstract:We propose a novel method to guide THz radiation with low losses along thin layers of water. This approach is based on the coupling of evanescent surface fields at the opposite sides of the thin water layer surrounded by a dielectric material, which leads to a maximum field amplitude at the interfaces and a reduction of the energy density inside the water film. In spite of the strong absorption of water in this frequency range, calculations show that the field distribution can lead to propagation lengths of several centimeters. By means of attenuated total reflection measurements we demonstrate the coupling of incident THz radiation to the long-range surface guided modes across a layer of water with a thickness of 24 μm. This first demonstration paves the way for THz sensing in aqueous environments.

THz Detection of Biomolecules in Aqueous Environments—Status and Perspectives for Analysis Under Physiological Conditions and Clinical use

“…A sophisticated approach to extend the propagation path length is shown by inverse micelles, which reduce the overall absorption of the system [16,108]. In order to characterize absorbing liquids, the general requirement of short propagation distances has also led to the development of wave guiding structures for tuning electromagnetic field liquid interactions [24,121,140].…”

“…For instance, as demonstrated for DNA detection, the differential technique is extremely useful to enhance the signal contrast, thereby increasing the sensitivity by several orders of magnitude [7]. The recently issued dielectric long-range guided mode with absorption could provide another possible construct [139,140]. Possibly, prospective experiments will demonstrate a sensitivity increase due to significantly increased interaction lengths between coupled THz waves and absorbing medium by using this mode.…”