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Path: ...!Xl.tags.giganews.com!local-2.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail NNTP-Posting-Date: Tue, 25 Jun 2024 15:14:48 +0000 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 Message-ID: <cfnl7j54d93jdanlrd1ais4hvh5hr1eei3@4ax.com> References: <v55qe6$20163$1@solani.org> <v571as$3rs0j$2@dont-email.me> <v58ab7$21a84$1@solani.org> <v59j4s$e196$1@dont-email.me> <k6kg7j5rqjd4r9igl9vk329h27pos4adr8@4ax.com> <v59obk$f0ue$1@dont-email.me> <36tg7jl5i74ui7rvmqhbg1jl9pldjehmvb@4ax.com> <v5a6f5$hji2$1@dont-email.me> <oqdh7jd0junt525da0fdgnolensva9h8ls@4ax.com> <v5ae7e$j0sj$1@dont-email.me> <n3lj7j9ojpmg5033ueb4ogp08ni791jb4j@4ax.com> <f6rj7j10u7d4tspqpi3313km2hop57j595@4ax.com> <v5dt05$1f7m7$1@dont-email.me> User-Agent: ForteAgent/8.00.32.1272 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 163 X-Trace: sv3-OuwhS5R6117HfQ8FfPJliN9erd6LM3nUX7iUOObWbVtchxXPtFcLdjGHDFgbIvBBRtlVNTFa6G2N0H/!+jcmfjTRZ9jwEQpAcs0JFb7+S7pfK1iodFKGzaLc2e7Q/QMeo7r6+MZKjr52ecPxKaiot5aaAHyF!NXhgeQ== X-Complaints-To: www.supernews.com/docs/abuse.html X-DMCA-Complaints-To: www.supernews.com/docs/dmca.html X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 Bytes: 7971 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.