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From: Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>
Newsgroups: sci.electronics.design
Subject: Re: how the laser happened
Date: Tue, 25 Jun 2024 20:46:32 -0000 (UTC)
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Jeroen Belleman <jeroen@nospam.please> wrote:
> On 6/25/24 12:50, Martin Brown wrote:
>> On 21/06/2024 14:05, john larkin wrote:
>>> There was a thread somewhere above about photon wave/particle duality.
>>> 
>>> 
>>> This is worth reading:
>>> 
>>> https://www.amazon.com/How-Laser-Happened-Adventures-Scientist/dp/0195153766
>>> 
>>> Einstein, in one of his fits of genius, predicted in around 1916 that
>>> under the right conditions, a photon could pass by an excited atom and
>>> the atom would kick in another photon, or add to the wave amplitude,
>>> depending on how you feel about these things. He called it stimulated
>>> emission. He also declared that the laws of thermodynamics made this
>>> effect impossible to use in practical situations.
>>> 
>>> In 1951, Charles Townes invented a work-around trick and built the
>>> maser, a gaseous microwave oscillator. His superiors thought he was
>>> crazy to dispute Einstein and almost threw him out of grad school, but
>>> it worked.
>> 
>> More interesting still nature beat him to it.
>> 
>> The natural source W3(OH) dense molecular cloud which has hydroxyl 
>> masers pumped by UV bright young stars embedded in it.
>> 
>> Very bright ultra narrow band point sources on a fuzzy nebulous object.
>> 
>> https://articles.adsabs.harvard.edu/pdf/1981MNRAS.194P..25S
>> 
> [...]
> The idea has been around for a while. Scifi writer Larry Niven
> used it in his Ringworld series of stories. (A ringworld meteorite
> defence system strips bare the hull of a space ship on a collision
> course with the ringworld surface.)
> 
> Jeroen Belleman
> 

Of course the Ringworld is dynamically unstable, so it wouldn’t matter that
much if it got hit. ;)

Cheers 

Phil Hobbs 

-- 
Dr Philip C D Hobbs  Principal Consultant  ElectroOptical Innovations LLC /
Hobbs ElectroOptics  Optics, Electro-optics, Photonics, Analog Electronics