Path: ...!Xl.tags.giganews.com!local-2.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail NNTP-Posting-Date: Mon, 24 Jun 2024 00:05:38 +0000 From: john larkin Newsgroups: sci.electronics.design Subject: Re: how the laser happened Date: Sun, 23 Jun 2024 17:05:38 -0700 Message-ID: References: <1ghb7jt3882078r19n6jjgtirv25q27805@4ax.com> <36tg7jl5i74ui7rvmqhbg1jl9pldjehmvb@4ax.com> User-Agent: ForteAgent/8.00.32.1272 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Lines: 124 X-Trace: sv3-jTOu8cX7DmEKp9EqdKt/71812/ikRkDUesiCNCUfciNyUi8WgFxw88qjBPPS7jeTDdHsGSweOioGtwH!VBFc38XEKPvGjogMzGtofeNi/p+8mlPYbjEOfqpE2zA1JXRWDEwJ2pYr7hMQtHlyMXLjHbRYr3wD!fiLhMA== 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: 6048 On Sun, 23 Jun 2024 22:09:42 -0000 (UTC), Phil Hobbs wrote: >john larkin wrote: >> On Sun, 23 Jun 2024 18:08:52 -0000 (UTC), Phil Hobbs >> wrote: >> >>> john larkin wrote: >>>> On Sun, 23 Jun 2024 16:39:56 -0000 (UTC), Cursitor Doom >>>> 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 wrote in >>>>>> : >>>>>> >>>>>>> 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 wrote in >>>>>>>> <1ghb7jt3882078r19n6jjgtirv25q27805@4ax.com>: >>>>>>>> >>>>>>>>> On Fri, 21 Jun 2024 17:56:36 +0100, Cursitor Doom >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> On Fri, 21 Jun 2024 06:05:21 -0700, 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. >>>>>>>>>>> >>>>>>>>>>> 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. Nature seems to use any effect that's not flat impossible, whether biologists approve or not.