From: mailrus!gatech!mit-eddie!media.mit.edu!minsky@uunet.uu.net
Subject: Re:  Integrated laser arrays for HMDs
Date: Wed, 6 Nov 1991 17:25:35 GMT
Organization: MIT Media Laboratory



In article <1991Nov6.024220.1048@milton.u.washington.edu> adobe!!
epperson@decwrl.dec.com (Mark Epperson) writes:

>In article <1991Nov1.174248.19885@milton.u.washington.edu> cdshaw@cs.
>ualberta.ca (Chris Shaw) writes:
>
>%In article Christopher Fry <70353.3056@CompuServe.COM% writes:
>%..enthusiastically about lasers on a chip
>%%Laser diode use a LOT of current ...
>%It chould be pointed out that the most efficient lasers are on the order
>%of 25% efficient (Carbon Dioxide lasers, if I remember right). That's a 
>
>Look at the latest issue of Scientific American for the article on
>Surface Emmiting Lasers.  They describe a future version of their
>laser which will be far more efficient.

CO2 lasers emit infrared, so not useful for human vision.  But in any
case the efficiency issue seems irrelevant.  A beam of light entering
the eye will be millions of times more visible than the same amount of
light emitted and reflected from an external object. Because we're
talking about microwatts of light inside the eye, the efficiency of
the emitter is negligable.