Observation of Extra Photon Recoil in a Distorted Optical Field

Satyanarayana Bade, Lionel Djadaojee, Manuel Andia, Pierre Cladé, and Saïda Guellati-Khelifa

Phys. Rev. Lett. 121, 073603 – Published 16 August 2018

Abstract

Light carries momentum which induces on atoms a recoil for each photon absorbed. In vacuum, for a monochromatic beam of frequency $ν$ , the global momentum per photon is bounded by general principles and is smaller than $h ν / c$ leading to a limit on the recoil. However, locally this limit can be broken. In this Letter, we give a general formula to calculate the recoil in vacuum. We show that in a laser beam with a distorted optical field, there are regions where the recoil can be higher than this limit. Using atoms placed in those regions we are able to measure directly the extra recoil.

Received 8 December 2017
Revised 19 June 2018

DOI:https://doi.org/10.1103/PhysRevLett.121.073603

Physics Subject Headings (PhySH)

Angular momentum of light Atom interferometry Cold gases in optical lattices Lasers Light-matter interaction

Atomic, Molecular & Optical

Authors & Affiliations

Satyanarayana Bade¹, Lionel Djadaojee¹, Manuel Andia^1,*, Pierre Cladé^1,†, and Saïda Guellati-Khelifa^1,2,‡

¹Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL University, Collège de France, 4 place Jussieu, 75005 Paris
²Conservatoire National des Arts et Métiers, 292 rue Saint Martin, 75003 Paris, France

^*Present address: University of Strathclyde, Department of Physics, SUPA, Glasgow G4 0NG, United Kingdom.
^†pierre.clade@lkb.upmc.fr
^‡saida.guellati@lkb.upmc.fr