PHO_ton

[John Young <jya@pipeline.com>]

   New Scientist, 24 February 1996:

   "Trick of the light fools forgers."

      Researchers at U-Conn Storrs are developing security
      systems that use a new kind of invisible code -- the
      phase of light. A transparent phase mask over a photo on
      a credit card would make it very difficult to forge. The
      authenticity of the card is checked by a reader composed
      of a laser light source and a device called an optical
      correlator. Bahram Javidi, leading Storrs researcher,
      will publish the latest findings in SPIE proceedings,
      called "Optical Security and Counterfeit Deterrent
      Techniques" (v 2659).

   "Good connections, quantum style."

      For quantum computers of the future, any "noise" in the
      connection between sender and receiver could prove
      disastrous. The problem is that the data in such
      computers will be held in the form of individual photons
      and, since quantum theory states that they cannot be
      checked because the mere act of measuring them will
      transform them, every error that creeps in will go
      uncorrected. Now IBM researchers have come up with a way
      to make the connection crystal clear (PRL, v 76, p 722).
      [Cf. recent thread "IBM's Breakthrough."]
 

   PHO_ton