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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 08:14:49 -0700
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On Tue, 25 Jun 2024 09:55:00 +0200, Jeroen Belleman
<jeroen@nospam.please> wrote:

>On 6/25/24 00:02, john larkin wrote:
>> On Mon, 24 Jun 2024 16:22:31 -0400, Joe Gwinn <joegwinn@comcast.net>
>> 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.
>>>
>>> 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
>> 
>> I was thinking of amplification to improve night vision.
>> 
>
>Nature chose the cheaper way: A cascade of amplifiying chemical
>reactions.
>
>Jeroen Belleman

A photon might be absorbed and lost without invoking a chemical
response in the retina, and be wasted. A lossless preamplifier would
help.

There would be bandwidth issues, but nature is inventive.

The idea could be experimentally tested, fairly easily.