Re: laser safety

["1LT Philip Hypes"<1lt_philip_hypes_at_chppm8__apgea@chppm-ccmail.apgea.army.mil>]

     Mr. Charris wrote:
     
     "I'm curious, what about a laser beam from one of these
     products into the eyes of a person wearing glasses? Wouldn't the 
     optics magnify to such an extent as to significantly increase the 
     chances of injury?"
     
     If I recall my laser safety training correctly, optical systems can
     greatly increase the hazard of viewing a laser beam.  That is because
     systems such as binoculars, telescopes, or rifle scopes have large
     objective lenses that collect many times more light than the eye
     alone, and then deliver it all to the eye.  This is much more of a
     concern for beams that are larger than the eye;  if the beam diameter 
     is smaller than the eye, the eye can absorb all the energy on it's 
     own.  In this case, an optical system may concentrate the energy in a
     smaller area of the retina (or whatever part of the eye is at risk
     for the wavelength in question), or, depending on what the optical
     system was designed to do, it could theoretically disperse the energy 
     to some degree.  The lens material may also absorb a measurable
     amount of the laser energy, reducing the beam intensity.  This is not
     to say that glasses will protect you, but for laser pointers at close
     range, I doubt they'd make a big difference.
     
     Phil Hypes
     1LT_Philip_Hypes_at_chppm8__apgea@chppm-ccmail.apgea.army.mil


************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html