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From: Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>
Newsgroups: sci.electronics.design
Subject: Re: how the laser happened
Date: Mon, 24 Jun 2024 16:47:57 -0000 (UTC)
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john larkin <jl@650pot.com> wrote:
> On Mon, 24 Jun 2024 00:22:06 -0000 (UTC), Phil Hobbs
> <pcdhSpamMeSenseless@electrooptical.net> wrote:
> 
>> john larkin <jl@650pot.com> wrote:
>>> On Sun, 23 Jun 2024 22:09:42 -0000 (UTC), Phil Hobbs
>>> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>>> 
>>>> john larkin <jl@650pot.com> wrote:
>>>>> On Sun, 23 Jun 2024 18:08:52 -0000 (UTC), Phil Hobbs
>>>>> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>>>>> 
>>>>>> john larkin <jl@650pot.com> wrote:
>>>>>>> On Sun, 23 Jun 2024 16:39:56 -0000 (UTC), Cursitor Doom
>>>>>>> <cd999666@notformail.com> wrote:
>>>>>>> 
>>>>>>>> On Sun, 23 Jun 2024 05:03:34 GMT, Jan Panteltje wrote:
>>>>>>>> 
>>>>>>>>> On a sunny day (Sat, 22 Jun 2024 17:23:40 -0000 (UTC)) it happened
>>>>>>>>> Cursitor Doom <cd999666@notformail.com> wrote in
>>>>>>>>> <v571as$3rs0j$2@dont-email.me>:
>>>>>>>>> 
>>>>>>>>>> On Sat, 22 Jun 2024 06:19:49 GMT, Jan Panteltje wrote:
>>>>>>>>>> 
>>>>>>>>>>> On a sunny day (Fri, 21 Jun 2024 11:32:56 -0700) it happened john
>>>>>>>>>>> larkin <jl@650pot.com> wrote in
>>>>>>>>>>> <1ghb7jt3882078r19n6jjgtirv25q27805@4ax.com>:
>>>>>>>>>>> 
>>>>>>>>>>>> On Fri, 21 Jun 2024 17:56:36 +0100, Cursitor Doom <cd@notformail.com>
>>>>>>>>>>>> wrote:
>>>>>>>>>>>> 
>>>>>>>>>>>>> On Fri, 21 Jun 2024 06:05:21 -0700, john larkin <jl@650pot.com>
>>>>>>>>>>>>> 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.
>>>>>>>>>>>>>> 
>>>>>>>>>>>>>> In 1960, Theodore Maiman at HRL made the first ruby laser, and Bell
>>>>>>>>>>>>>> Labs soonafter made a HeNe.
>>>>>>>>>>>>>> 
>>>>>>>>>>>>>> What's interesting is that any decent neon sign shop could have
>>>>>>>>>>>>>> built a HeNe laser in 1920.
>>>>>>>>>>>>>> 
>>>>>>>>>>>>>> HRL sounds like a very cool place, up in the hills above Malibu.
>>>>>>>>>>>>> 
>>>>>>>>>>>>> Wasn't that where Jane Mansfield used to go out bathing?
>>>>>>>>>>>>> 
>>>>>>>>>>>>> 
>>>>>>>>>>>> Keep your mind on electronics, young man.
>>>>>>>>>>>> 
>>>>>>>>>>>> The Getty Museum is in Malibu. Go there if you can. Hearst Castle,
>>>>>>>>>>>> too,
>>>>>>>>>>>> up the road a bit.
>>>>>>>>>>> 
>>>>>>>>>>> I've been to Malibu, even did some work there...
>>>>>>>>>>> Did not go to any museum, but did go to the beach.
>>>>>>>>>> 
>>>>>>>>>> Did you see Jane? What about lobsters? Any lobsters around? 
>>>>>>>>> 
>>>>>>>>> Na, but some other beatiful women I met.
>>>>>>>>> Last time we went looking for edible seaweed ...
>>>>>>>> 
>>>>>>>> Argh! Never mind. I believe Jane had terrible problems with lobsters when 
>>>>>>>> she went out bathing in Malibu. But you don't know anything about that, 
>>>>>>>> clearly. It obviously wasn't publicised in Holland.
>>>>>>> 
>>>>>>> This thread is about lasers, not lobsters. 
>>>>>>> 
>>>>>>> 
>>>>>> 
>>>>>> Well, Schawlow famously said, ?Anything will lase, if you hit it hard
>>>>>> enough.?
>>>>>> 
>>>>>> I expect that includes lobsters. 
>>>>>> 
>>>>>> Cheers 
>>>>>> 
>>>>>> Phil Hobbs 
>>>>> 
>>>>> But no, seriously, there must be some laser action, or at least some
>>>>> sort of stimulated emission, some sort of super-fluorescence, in
>>>>> nature somewhere. 
>>>> 
>>>> Sure. Cosmic masers occur in interstellar giant molecular clouds, for
>>>> instance. 
>>>> 
>>>> The lifetime of suitable upper states drops steeply with increasing energy,
>>>> which means that visible laser action requires much stronger pumping. 
>>>> 
>>>> While that can in principle happen naturally, it would be in places with a
>>>> lot of other stuff going on, so it would be less noticeable. 
>>>> 
>>>> You don?t have resonators in interstellar space, so it wouldn?t be highly
>>>> directional. 
>>>> 
>>>> Cheers 
>>>> 
>>>> Phil Hobbs 
>>> 
>>> I was thinking about a biological laser too.
>>> 
>>> I could imagine an eyeball with some sort of stimulated emission
>>> effect, in the vitreus humor or in the retina, to improve night
>>> vision, basically a photon amplifier.
>> 
>> Difficult. For a start, you need a pump source of high intensity and
>> narrowish bandwidth, and there are no biological examples that I know of. 
> 
> There are chemical lasers.
> 
> 

And nuclear ones!

Cheers 

Phil “certified laser jock” Hobbs 

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