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CATEGORIES:Cavendish Physical Society
SUMMARY:Electromagnetic surfaces from butterflies to battl
 eships - Professor J Roy Sambles\, School of Physi
 cs\, University of Exeter
DTSTART;TZID=Europe/London:20090513T161500
DTEND;TZID=Europe/London:20090513T171500
UID:TALK16465AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/16465
DESCRIPTION:*Question:*  _What do graceful\, flickering\, vivi
 dly iridescent\, tropical butterflies have in comm
 on with dull grey ponderous battleships?_ \n\n*Ans
 wer:* _Structured materials give somewhat surprisi
 ng electromagnetic responses._\n\nTaking little ot
 her than common cuticle\, loaded with a small amou
 nt of melanin\, butterflies have evolved some stun
 ning microstructures in their wing scales. These s
 tructured surfaces\, often only microns thick\, ac
 t as selective reflectors and polarizers as well a
 s being sometimes very strong scatterers (white) o
 r very strong absorbers (black) of electromagnetic
  radiation. This use of structure in nature to giv
 e striking effects when interacting with visible r
 adiation is limited to dielectrics. When it comes 
 to synthetic structures we may also use metals. St
 ructured metals can also lead to unexpected effect
 s such as negative index materials\, perfect lensi
 ng and ‘cloaking’. Even at very long wavelengths (
 microwaves and beyond) where metals are expected t
 o behave as almost perfect mirrors they can be str
 uctured to be almost perfect absorbers. \nThis tal
 k will illustrate briefly the wonderful structural
  colours of butterflies focusing primarily on some
  recent developments in the physics of structured 
 metals for use at microwave frequencies. \n
LOCATION:Pippard Lecture Theatre\, Cavendish Laboratory
CONTACT:Leona Hope-Coles
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