EPL, 77 (2007) 64003
DOI: 10.1209/0295-5075/77/64003

Magic angle detection of nonlinear Newton-Wigner times at interfaces

G. Loas¹, C. Bonnet¹, K. Dunseath², D. Chauvat¹, O. Emile¹ and A. Le Floch<sup>1

1</sup>  Laboratoire d'Electronique Quantique-Physique des Lasers, UMR CNRS 6627, Université de Rennes I 35042 Rennes Cedex, France
²  Simulations des Interactions entre Molécules, Photons et Atomes, UMR CNRS 6627, Université de Rennes I 35042 Rennes Cedex, France

received 21 July 2006; accepted in final form 29 January 2007; published March 2007
published online 5 March 2007

Abstract
The existence of nonlinear Newton-Wigner delay-times in the femtosecond range is demonstrated using a pulsed laser beam with rotating polarization impinging on an interface together with a time-resolved differential detection at a "magic angle". Experimentally, increasing the incident power by a factor of 10 leads to a decrease in the delay-time by more than 70 at total reflection. In contrast, below the critical incidence angle, the same power variation leads to a huge increase in the delay-time. Intrinsic nonlinear Newton-Wigner delays are also expected in quantum reflection and the magic angle method could be extended to shorter pulses, down to the attosecond domain. Possible applications are discussed.

PACS
42.25.Gy - Edge and boundary effects; reflection and refraction.
42.25.Ja - Polarization.
42.65.-k - Nonlinear optics.

© Europhysics Letters Association 2007