Path: ...!Xl.tags.giganews.com!local-1.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail NNTP-Posting-Date: Fri, 21 Jun 2024 13:05:21 +0000 From: john larkin Newsgroups: sci.electronics.design Subject: how the laser happened Date: Fri, 21 Jun 2024 06:05:21 -0700 Message-ID: User-Agent: ForteAgent/8.00.32.1272 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 34 X-Trace: sv3-ZWz7jJ03Fz1JaXoN86tjGjnoiB/g7ILNPYrKKMFIZnSeGq2pk/vWBIkOyLyryKMCK+mDdwShbomv3cJ!V83vBwyXGXOmyE5YNYLy2FW0QEsKtFDTNRjna6Cs6J062eSpUWeDpgZbOVonzy0J/erUbd+iG5kI!/YsjNQ== 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: 2152 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. https://www.hrl.com/ Some details: https://www.aps.org/archives/publications/apsnews/200312/history.cfm