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Failed to connect to MySQL: (1203) User howardkn already has more than 'max_user_connections' active connectionsPath: ...!weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Lasse Langwadt Newsgroups: sci.electronics.design Subject: Re: how the laser happened Date: Mon, 24 Jun 2024 22:45:25 +0200 Organization: A noiseless patient Spider Lines: 31 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Mon, 24 Jun 2024 22:45:26 +0200 (CEST) Injection-Info: dont-email.me; posting-host="96ee22ec3c0de7dfe96f70353033eb30"; logging-data="1168399"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX185sUzg+UgOSNUEigr17vGNF14t4tjhBqQ=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:SFHgFP53ifyGHo0fqBaag77zczo= In-Reply-To: Content-Language: en-US Bytes: 2255 On 6/21/24 15:05, 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. > you could build a laser in your living room if you want to http://jarrodkinsey.org/co2laser/co2laser.html