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From: john larkin <jl@650pot.com>
Newsgroups: sci.electronics.design
Subject: Re: how the laser happened
Date: Tue, 25 Jun 2024 15:41:48 -0700
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On Tue, 25 Jun 2024 17:43:56 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:

>On Tue, 25 Jun 2024 08:19:03 -0700, john larkin <jl@650pot.com> wrote:
>
>>On Tue, 25 Jun 2024 11:50:05 +0100, Martin Brown
>><'''newspam'''@nonad.co.uk> 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
>>>
>>>> What's interesting is that any decent neon sign shop could have built
>>>> a HeNe laser in 1920.
>>>
>>>They would have needed to make the mirror just cavity right though.
>>
>>I know a guy who built a HeNe. It wasn't hard.
>>
>>T>
>>>A nitrogen gas UV pulsed laser is possible just by getting the pressure 
>>>right and creating the  population inversion. Self starting - there was 
>>>a (dangerous) experiment in SciAm Amateur Scientist column to do it 
>>>sometime in the 1970's. June 1974 in fact - cover shows the BZ reaction.
>>>
>>>https://www.scientificamerican.com/article/the-amateur-scientist-1974-06/
>>>
>>>The failure to discover fullerenes in soot was a lot more surprising 
>>>since they were there all the time since the invention of fire just 
>>>waiting to be extracted by benzene. For a long time space dust had a 
>>>spectrum that could not be reproduced on Earth by any known compound.
>>>
>>>Much like Helium was in the sun but more pervasive.
>>
>>Too many powerful old farts declare things to be impossible.
>
>.<https://en.wikipedia.org/wiki/Planck%27s_principle>
>
>This is often paraphrased as "Science progresses one funeral at a
>time".
>
>Joe Gwinn

I see the same thing in electronic design. People favor accepted
practice, validated in textbooks, and apply all their intelligence to
showing how new ideas won't work.

A recent case is deciding that the LC's at the output of a switching
power supply are "a filter" so must follow  classical filter theory,
pole-zeros and Butterworths and such. I tell them "It's just a power
supply."