![]() Additionally, there are enough raw parts out there that you could build the equipment you need for this laser for under 3k.ĪPOLLO uses ~ 100 ps, 100 mJ pulses, but it should be as feasible to use 1 ns, 1 J pulses. I know people who got lasers that would work for this application for just the cost of shipping. The industry is constantly turning over from lamp pumped lasers to DPSS lasers and, as a result, if you can get the electricity and know to be safe with power supplies, you can get a lamp pumped laser for next to nothing. ![]() Getting your hands on the laser is not actually that hard if you know what you're doing. Just 1-3 W would probably be enough if you had good detectors. You don't need a megawatt or even 100 W of average power. We need to distinguish between average and peak power here. I guess you could do all these things on your own, but you would need about $1 million and a couple years of time to set it up. And you need to set this all up in a place with minimal background light and minimal atmospheric distortion (seeing). You need a big telescope to maximize the number of photons you get (we used the 3.5 meter telescope at Apache Point). You need fancy filters and timing electronics, because, when you are only getting 1 photon back, you need to turn the detectors on in as little a time as possible to minimize false detections from background light. ![]() You need sensitive detectors because, even if you shoot 10 17 photons up, you're only going to get about 1 photon back (we used avalanche photodiodes). You need laser that can shoot enough photons in a short pulse that you'll get some back in the return pulse (shoot 10 17 green 532 nm photons per pulse). I was a grad student on the APOLLO (Apache Point Observatory Lunar Laser Ranging Operation) project that was shown on Mythbusters. We make our world significant by the courage of our questions and by the depth of our answers. For more open-ended questions, try /r/AskScienceDiscussion | Sign up to be a panelist!.Looking for flair? Sign up to be a panelist!.Neuroscience, Neurology, Neurochemistry, Cognitive NeuroscienceĪsk Anything Wednesday - Engineering, Mathematics, Computer scienceĪsk Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, PsychologyĪsk Anything Wednesday - Economics, Political Science, Linguistics, AnthropologyĪsk Anything Wednesday - Physics, Astronomy, Earth and Planetary Science Medicine, Oncology, Dentistry, Physiology, Epidemiology, Infectious Disease, Pharmacy, Human Body Psychology, Cognitive Psychology, Developmental Psychology, Abnormal, Social Psychology Social Science, Political Science, Economics, Archaeology, Anthropology, Linguisticsīiology, Evolution, Morphology, Ecology, Synthetic Biology, Microbiology, Cellular Biology, Molecular Biology, Paleontology ![]() Mechanical Engineering, Electrical Engineering, Structural Engineering, Computer Engineering, Aerospace EngineeringĬhemistry, Organic Chemistry, Polymers, Biochemistry Mathematics, Statistics, Number Theory, Calculus, AlgebraĪstronomy, Astrophysics, Cosmology, Planetary FormationĬomputing, Artificial Intelligence, Machine Learning, ComputabilityĮarth Science, Atmospheric Science, Oceanography, Geology Theoretical Physics, Experimental Physics, High-energy Physics, Solid-State Physics, Fluid Dynamics, Relativity, Quantum Physics, Plasma Physics /r/AskScienceDiscussion: For open-ended and hypothetical questions.FAQ: In-depth answers to many popular questions.Weekly Features: Archives of AskAnything Wednesday, FAQ Fridays, and more!.Be civil: Remember the human and follow Reddiquette.Report comments that do not meet our guidelines, including medical advice.Downvote anecdotes, speculation, and jokes.Upvote on-topic answers supported by reputable sources and scientific research.Answer questions with accurate, in-depth explanations, including peer-reviewed sources where possible.Please read our guidelines and FAQ before posting
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