RE: Melanoma cancer/UV info

["Neil, David M" <neildm@id.doe.gov>]

The photon energy (= color) is determined by the energy difference between
the excited and ground states, and is highly monochromatic, in proportion to
the purity of the fluorescing substance. The coherency is what
differentiates the laser, and this comes about by the stimulation of photon
emissions by previously emitted photons.

Much like the electron cascade in a GM tube.

Dave Neil		neildm@id.doe.gov

		Everyone has a photographic memory. Some don't have film.

> -----Original Message-----
> From:	Wright, Will (DHS-PSB) [SMTP:WWright2@dhs.ca.gov]
> Sent:	Friday, August 11, 2000 9:43 AM
> To:	Multiple recipients of list
> Subject:	RE: Melanoma cancer/UV info
> 
> That answers the beam production question, what about the "purity" of the
> apparent monochromatic beam.  Is the characteristic color due to the
> absolute 100% simultaneous shifts or is there some fluctuation between
> say,
> 90 and 100.  Ordinary light is dispersed over short distances as well.
> 
> 		-----Original Message-----
> 		From:	ruth_weiner [mailto:ruth_weiner@email.msn.com]
> 		Sent:	Thursday, August 10, 2000 8:33 PM
> 		To:	Multiple recipients of list
> 		Subject:	Re: Melanoma cancer/UV info
> 
> 		Just a note about lasers: LASER is an acronym for Light
> Amplification by
> 		Stimulated Emission of Radiation.  The ruby is not a filter,
> but the source
> 		of the laser light.  A laser is "primed" by creating a
> metastable situation
> 		where an energy state above the ground state (lowest
> potential energy) is
> 		overpopulated with electrons.  When stimulated, the
> electrons drop
> 		together -- in phase -- from the higher energy state to a
> lower one.  the
> 		characteristic red light of a ruby laser is this emission.
> Laser light is
> 		coherent -- the waves are all in phase -- which gives it its
> unusual
> 		penetrating power, and which is why you can bounce a laser
> beam off the
> 		moon.  Ordinary light (e.g. red neon light) is incoherent
> and disperses when
> 		beamed a long distance.
> 
> 		Ruth Weiner
> 		ruth_weiner@msn.com
> 		-----Original Message-----
> 		From: Wright, Will (DHS-PSB) <WWright2@dhs.ca.gov>
> 		To: Multiple recipients of list
> <radsafe@romulus.ehs.uiuc.edu>
> 		Date: Thursday, August 10, 2000 2:24 PM
> 		Subject: RE: Melanoma cancer/UV info
> 
> 
> 		>Visible light from fluorescent lamps produce UV in addition
> to the total
> 		>spectrum of visible light waves as well which combined
> appear as
> 		>white(heterochromatic) and very dispersed.  Fluorescent
> lights are filtered
> 		>with the plastic cover to reduce the UV levels.  Lasers
> produce
> 		>monochromatic light either red or green and can concentrate
> the beam, I am
> 		>not sure these beams are pure since the rubies etc used act
> as filters
> 		only?
> 		>These concentrated beams produce heat much the same way
> radiowaves and
> 		>microwaves do and indirectly form reactive products that
> might effect DNA.
> 		>
> 
> 
> 
> 	
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