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From: Joe Gwinn <joegwinn@comcast.net>
Newsgroups: sci.electronics.design
Subject: Re: how the laser happened
Date: Mon, 24 Jun 2024 16:22:31 -0400
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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. 

Biology does make meta surfaces of various kinds, usually to make
reflectors impossible to make any other way, from beetles that look
iridescent to bird feathers.


>> Nature seems to use any effect that's not flat impossible, whether
>> biologists approve or not.

True, if there is a need.  Laser eyes seem like it would attract the
wrong kind of attention.


Joe Gwinn