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SUMMARY:The sensitivity of the human eye to the polarisation of light - Dr
  Juliette McGregor\, University of Bristol
DTSTART:20131101T130000Z
DTEND:20131101T140000Z
UID:TALK47083@talks.cam.ac.uk
CONTACT:John Mollon
DESCRIPTION:From the zenith of the clear blue sky at sunset\, to the ubiqu
 itous liquid crystal display (LCD)\, sources of polarised light are everyw
 here. Yet our ability to observe the polarisation state of light with the 
 naked eye alone is not widely known. When exposed to a source of linearly 
 polarised light the observer sees a faint visual phenomenon consisting of 
 a yellow hourglass flanked by blue-purple regions. This image extends for 
 a few degrees around the fixation point and fades in a couple of seconds i
 f the angle of polarisation is not altered. The phenomenon is referred to 
 as ‘Haidinger’s brush’ after the mineralogist who first reported it.
 \n\nWhilst considerable effort has been directed toward testing polarizati
 on vision in other animals\, the limits of human polarisation sensitivity 
 remain largely uncharacterized and the origin of the effect is subject to 
 dispute. In this talk I will describe the physical mechanisms that have be
 en proposed to explain Haidinger’s brush\, consider their plausibility a
 nd present our initial attempts at characterising the human polarisation s
 ensitivity threshold. \n
LOCATION:Kenneth Craik Room\, Craik-Marshall Building\, Downing Site
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