Path: ...!local-3.nntp.ord.giganews.com!Xl.tags.giganews.com!local-1.nntp.ord.giganews.com!news.giganews.com.POSTED!not-for-mail NNTP-Posting-Date: Mon, 24 Jun 2024 20:22:31 +0000 From: Joe Gwinn Newsgroups: sci.electronics.design Subject: Re: how the laser happened Date: Mon, 24 Jun 2024 16:22:31 -0400 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=us-ascii Content-Transfer-Encoding: 7bit Lines: 139 X-Usenet-Provider: http://www.giganews.com X-Trace: sv3-wHR++ZIizTzGJMu/pIQdDTdr3W/eNEW1uwORCgYgZ7egYYDgNxGKptSsJlRGQt9fcoMkqvzdCPP59GA!3tIW3aA3tIQAzMLIQ7+9ZsUgxYE7uw4P5vfvImbLvqWOWlFT6TIrOkBbpqaZ44tBZBkxJkk= X-Complaints-To: abuse@giganews.com X-DMCA-Notifications: http://www.giganews.com/info/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: 6966 On Mon, 24 Jun 2024 00:22:06 -0000 (UTC), Phil Hobbs wrote: >john larkin wrote: >> 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. > >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