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Amplification of the evanescent field of free electrons

Amplification of the evanescent field of free electrons
Amplification of the evanescent field of free electrons
We show that the conversion of the evanescent field of free electrons into optical radiation can be enhanced by amplifying the electrons' evanescent field. In the same way a layer of plasmonic metal can be used to amplify evanescent fields in the 'poor-man's superlens', it can be used to enhance Smith-Purcell radiation.

The electromagnetic energy of free electrons exists in the form of evanescent waves and can be decoupled into light only when they are in close proximity to a slow-wave medium or optical inhomogeneity. Since the exponentially decay rate of such evanescent waves is proportional to the ratio of the frequency of the electromagnetic field to the velocity of the particle, high velocity, relativistic particles are more efficient in generating light in the optical part of the electromagnetic spectrum. Here, instead of increasing the energy of the particles to gain a higher level of conversion, we utilize a thin silver layer to amplify the rapidly decaying evanescent waves of non-relativistic free electrons. A silver layer a few tens of nanometres thick placed between the free electrons and nano-grating provides an order of magnitude enhancement of Smith-Purcell radiation in the UV range.
So, J.K.
06a7afea-61c2-439d-9ac4-047ea21a909b
Ou, J-Y.
3fb703e3-b222-46d2-b4ee-75f296d9d64d
Adamo, G.
73480dbd-5d3e-415a-b569-9606b3dbeecc
MacDonald, K.F.
76c84116-aad1-4973-b917-7ca63935dba5
García de Abajo, F.J.
68958b41-966f-49ef-9578-d0ffa446b33e
Zheludev, N.I.
32fb6af7-97e4-4d11-bca6-805745e40cc6
So, J.K.
06a7afea-61c2-439d-9ac4-047ea21a909b
Ou, J-Y.
3fb703e3-b222-46d2-b4ee-75f296d9d64d
Adamo, G.
73480dbd-5d3e-415a-b569-9606b3dbeecc
MacDonald, K.F.
76c84116-aad1-4973-b917-7ca63935dba5
García de Abajo, F.J.
68958b41-966f-49ef-9578-d0ffa446b33e
Zheludev, N.I.
32fb6af7-97e4-4d11-bca6-805745e40cc6

So, J.K., Ou, J-Y., Adamo, G., MacDonald, K.F., García de Abajo, F.J. and Zheludev, N.I. (2012) Amplification of the evanescent field of free electrons. SPIE Photonics Europe 2012, Belgium. 16 - 19 Apr 2012.

Record type: Conference or Workshop Item (Poster)

Abstract

We show that the conversion of the evanescent field of free electrons into optical radiation can be enhanced by amplifying the electrons' evanescent field. In the same way a layer of plasmonic metal can be used to amplify evanescent fields in the 'poor-man's superlens', it can be used to enhance Smith-Purcell radiation.

The electromagnetic energy of free electrons exists in the form of evanescent waves and can be decoupled into light only when they are in close proximity to a slow-wave medium or optical inhomogeneity. Since the exponentially decay rate of such evanescent waves is proportional to the ratio of the frequency of the electromagnetic field to the velocity of the particle, high velocity, relativistic particles are more efficient in generating light in the optical part of the electromagnetic spectrum. Here, instead of increasing the energy of the particles to gain a higher level of conversion, we utilize a thin silver layer to amplify the rapidly decaying evanescent waves of non-relativistic free electrons. A silver layer a few tens of nanometres thick placed between the free electrons and nano-grating provides an order of magnitude enhancement of Smith-Purcell radiation in the UV range.

Full text not available from this repository.

More information

Published date: April 2012
Venue - Dates: SPIE Photonics Europe 2012, Belgium, 2012-04-16 - 2012-04-19
Organisations: Optoelectronics Research Centre

Identifiers

Local EPrints ID: 379243
URI: https://eprints.soton.ac.uk/id/eprint/379243
PURE UUID: 43583572-db68-4005-87d3-bbd4c5bf46b3
ORCID for J-Y. Ou: ORCID iD orcid.org/0000-0001-8028-6130
ORCID for K.F. MacDonald: ORCID iD orcid.org/0000-0002-3877-2976
ORCID for N.I. Zheludev: ORCID iD orcid.org/0000-0002-1013-6636

Catalogue record

Date deposited: 21 Jul 2015 13:33
Last modified: 03 Aug 2019 00:38

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