Okay, let’s do some fun #optics trivia! Lessee... to start, my favorite: 2 meters squared of concentrated sunlight is enough to melt stone.
#Optics trivia: even in vacuum, light can travel slower than the speed of light! Beams with a “twist” in them can be slower, because the light is following the “twist,” not the straight line path. sciencenews.org/article/speed-…
#Optics trivia: optical tractor beams, which can trap and attract objects, do exist! ... but they can only trap stuff the size of bacteria. ekvv.uni-bielefeld.de/blog/uninews/e…
#optics trivia: Incidentally, some light beams can be said to be “superluminal,” even in vacuum, even though they may also be said to be “subliminal.” Don’t worry, nothing useful can be sent faster than the Einstein limit. skullsinthestars.com/2015/02/17/dr-…
#Optics trivia: the highest power laser ever fired is at Osaka University, producing a peak power of 2,000 trillion watts — albeit for a stunningly short time of a trillionth of a second. theconversation.com/worlds-most-po…
#Optics trivia: the shortest laser pulse ever produced was done in Zurich last year using an x-ray laser, producing a 43 attosecond-long pulse. That’s 43 millionths of a millionth of a millionth of a second. theconversation.com/worlds-most-po…
#Optics history trivia: free-space optical communication has been around a long time: in 1894, US army signalers used heliographs to communicate by light flashes between mountains 183 miles apart. en.m.wikipedia.org/wiki/Heliograph
#Optics trivia: a double rainbow comes from light bouncing twice in a water drop, instead of once. Third and fourth rainbows appear when light bounces 3 & 4 times, but they appear facing the sun. 5th order 1st seen only in 2012! earthsky.org/earth/first-ev…
#Optics trivia: in fact, rainbows of up to order 200 have been measured in the lab using a laser and a hanging water droplet. osapublishing.org/josab/abstract…
One more #Optics trivia for the night: lasers have been designed which produce fractal patterns as an output! Laser cavities are designed to shrink and duplicate the mode as it bounces back and forth. salford.ac.uk/research/sirc/…
#Optics trivia, from my own research! It turns out that the strange mathematics of infinite sets can manifest in light fields containing "optical vortices." americanscientist.org/blog/macroscop…
#Optics trivia: thanks to a phenomenon known as "superoscillations," it is theoretically possible to have (high-energy) gamma rays be emitted from a box which only contains (very low-energy) red light! iopscience.iop.org/article/10.108…
#Optics/astronomy trivia: a photon (light particle) takes about 8 minutes to get to Earth from sun’s surface... but approximately 100,000 years to get from sun’s core to surface! abc.net.au/science/articl…
#Optics trivia: LASERs create light by population inversion: having more atoms “excited” with energy than not. In 2013, the QASER was invented, which does not need any atoms in the excited state! journals.aps.org/prx/abstract/1…
#Optics trivia: in random scattering media, light can get “trapped” because wave interference around a closed path makes it most likely to return to its starting point! Known as light localization. cms.uni-konstanz.de/fileadmin/arch… 
#Optics/biology trivia: cuttlefish have W-shaped pupils, and nobody is completely sure why! It may allow them to detect color even though they only see in black and white. (Photo mine.) vcresearch.berkeley.edu/news/weird-pup…
(Now I want to explore the mathematics of W-shaped pupils myself.) #optics
#Optics/astrophysics trivia: it is theoretically possible to form a black hole with an intense concentration of light - a kugelblitz! en.m.wikipedia.org/wiki/Kugelblit…
#Optics trivia: rogue waves, the unpredictable, rare, and mysterious waves that occasionally destroy ships, have optical analogues. These analogues are used to better understand their ocean counterparts. skullsinthestars.com/2010/07/13/fre…
#Optics trivia: if you design your hotel with a nice shiny curved facade, you may be building a "death ray" targeting your guests. reviewjournal.com/news/vdara-vis…
#Optics trivia: It is not only possible, but useful, to build telescopes out of spinning pools of liquid metal like mercury. en.wikipedia.org/wiki/Liquid_mi…
#Optics trivia: Many people can actually see, faintly the polarization of light! The image viewed is known as Haidinger's brush. en.wikipedia.org/wiki/Haidinger…
#Optics trivia: the Möbius strip, a famous mathematical one-sided surface, actually appears in the polarization structure of beams of light under the right circumstances! skullsinthestars.com/2010/10/10/twi…
#Optics trivia: the optical glory, the rainbow effect seen on clouds from planes, sometimes manifests to mountain climbers as a massive human shadow called the “Brocken Spectre.” en.m.wikipedia.org/wiki/Brocken_s…
#Optics trivia: Humans can see ultraviolet light... provided they have the lenses of their eyes removed. petapixel.com/2012/04/17/the…
#Optics trivia: using the same total internal reflection that makes fiber optics work, you can guide light through a falling stream of water! skullsinthestars.com/2013/09/16/184…
#Optics trivia: researchers have designed a camera fast enough to capture the actual motion of light itself! (Though it does require multiple recordings.) This is an actual pulse of light moving. skullsinthestars.com/2012/01/04/a-c…
#Optics trivia: in Bose-Einstein condensates, light can be slowed to bicycle speeds or even stopped in place! This was first done in 1999 and 2001 by Lene Hau of Harvard. physicscentral.com/explore/action…
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