Nature444, 740-743 (7 December 2006) | doi:10.1038/nature05265; Received 21 February 2006; Accepted 19 September 2006
Thermal radiation scanning tunnelling microscopy
Yannick De Wilde1,6, Florian Formanek1,6,7, Rémi Carminati2, Boris Gralak3, Paul-Arthur Lemoine1, Karl Joulain4, Jean-Philippe Mulet2,6, Yong Chen5 and Jean-Jacques Greffet2
Laboratoire d'Optique Physique, Ecole Supérieure de Physique et de Chimie Industrielles, CNRS-UPR A0005, 10 rue Vauquelin, 75005 Paris, France
Laboratoire EM2C, Ecole Centrale Paris, CNRS, Grande Voie des Vignes, 92295 Châtenay-Malabry Cedex, France
Institut Fresnel, Faculté des Sciences et Techniques de St Jérôme, CNRS, case 161, Avenue Escadrille Normandie-Niemen, 13397 Marseille cedex 20, France
Laboratoire d'Etudes Thermiques, Ecole Nationale Supérieure de Mécanique et d'Aérotechnique, BP 109, 86960 Futuroscope Cedex, France
Laboratoire de Photonique et de Nanostructures, CNRS, Route de Nozay, 91460 Marcoussis, France, and Département de Chimie, Ecole Normale Supérieure, 24 Rue Lhomond, 75231 Paris Cedex 05, France
These authors contributed equally to this work.
Present addresses: Nanophotonics Laboratory-RIKEN, Wako, Saitama 351-0198, Japan (F.F.); Saint-Gobain Recherche, 39 Quai Lucien Lefranc, 93300 Aubervilliers, France (J.-P.M.).
Correspondence to: Yannick De Wilde1,6 Correspondence and requests for materials should be addressed to Y.D.W. (Email: dewilde@optique.espci.fr).
In standard near-field scanning optical microscopy (NSOM), a subwavelength probe acts as an optical 'stethoscope' to map the near field produced at the sample surface by external illumination1. This technique has been applied using visible1, 2, infrared3, terahertz4 and gigahertz5, 6 radiation to illuminate the sample, providing a resolution well beyond the diffraction limit. NSOM is well suited to study surface waves such as surface plasmons7 or surface-phonon polaritons8. Using an aperture NSOM with visible laser illumination, a near-field interference pattern around a corral structure has been observed9, whose features were similar to the scanning tunnelling microscope image of the electronic waves in a quantum corral10. Here we describe an infrared NSOM that operates without any external illumination: it is a near-field analogue of a night-vision camera, making use of the thermal infrared evanescent fields emitted by the surface, and behaves as an optical scanning tunnelling microscope11, 12. We therefore term this instrument a 'thermal radiation scanning tunnelling microscope' (TRSTM). We show the first TRSTM images of thermally excited surface plasmons, and demonstrate spatial coherence effects in near-field thermal emission.
