Rainbow Lasers · 9:28pm Apr 5th, 2019
In Spring Breakdown:
Rainbow Dash: I'm talkin' rainbow lasers!
Sunset Shimmer: Is that a thing?
Fascinating question...
It seem we are missing the scene where Twilight Sparkle explains why, whatever Equestrian magic may be, it isn’t laser light. Equestrian magic moves in curves, wrapping villains up in graceful spirals, with all the colours neatly separated. While lasers beams are straight lines of a single colour and usually only visible when the beam hits a surface.
Except this scene does actually look a bit like what you would get by taking a set of reasonably high power lasers, expanding the beams, and shining them up into a dark sky with plenty of water vapour to scatter the light.
What is a laser anyway? Time for some atomic physics. For this explanation you can picture an atom as lots of electrons whizzing around a nucleus. The electrons exist in orbitals with a fixed energy. When an atom is excited, the electrons are raised to a higher energy state. When an electron falls from a higher energy state back to a lower energy one it emits light with a wavelength, or colour, set by the difference of the energy levels. The energy levels of atoms of different elements vary, and change depending on the chemical environment, so different materials have different colours.
Those who were listening to Twilight and Timber Spruce’s small talk in Legend of Everfree will know that rubies are sapphire (aluminium oxide) with a trace of chromium. This addition creates a energy transition corresponding to the characteristic red light.
Such a crystal is at the heart of a ruby laser (the first laser, invented in 1960), which used a flash tube to ‘pump’ the electrons into the higher energy state. When an electron falls into the lower state, a photon of light is emitted. This photon then stimulates electrons in other atoms causing them to emit photons. Keep the crystal between two mirrors, and the photons will bounce back and forth, stimulating more and more, so we have Light Amplification by Stimulated Emission of Radiation - LASER.
As the colour of the light is fixed by the atomic energy levels, lasers are monochromatic - they emits beams of a single colour. You could perhaps tune it a little bit by heating your crystal, but not very much. If you want a different colour, you need a different crystal, or other medium, which will probably have quite different optical properties and need a different pumping mechanism. There are an enormous number of different types of laser on the market.
So is a rainbow laser a thing? As a rainbow is a continuous spectrum formed by the splitting of white light, a strict interpretation would suggest no. But you could get something while looks exactly the same to a human eye by combining laser beams of different colours, which does seem to be how the whole Elements of Harmony thing works.
You would actually only need three lasers as we have three photoreceptors in our eyes, so an appropriate combination of red, green, and blue can create any colour in the rainbow. Ponies have two-colour vision, so could simulate a rainbow with just two.
Coming back to the original question, we can also answer it by just typing “rainbow laser” into a search engine. Which reveals that yes. Rainbow lasers are a thing. Yours for only €16,000.
It's always felt weird to me how easily people accept the phenomenon of lasers. They feel so unnatural to me - requiring this weird unintuitive quantum behavior that we couldn't even have begun to understand without many years of work by many very smart people. It just kinda feels like humans hacked the universe. :)
(Google suggests that there do exist "natural" lasers, but they seem to require exotic conditions)
Chromium is just a great dopant.
I think she just wanted there to be rainbow lasers, and got them when she ponied up. :B
I mean, it's magic, she ain't gotta explain shit. :V
Lasers are what you get when you take a negative temperature material and allow it to warm up.
Dark Energy is Magic?
The shorter the laser pulse <=> the wider the rainbow.
5038800
There is quite a lot of weird unnatural stuff that we now just accept. Electric motors, radio communication, artificial satellites. Hacking the universe is what we do...
5038828
All depends on your favourite colour.
5038830
So if she had wanted giant bunny ears instead?
5038840
I'll leave dark energy for another time.
5038844
Time to start experimenting! :D
Given that this show has many children watching, one must bring up safety:
Way back in High School Physics (back then, we had to watch out for hungry gorgonopsids), the thing Mister Pillsbury said before breaking out the lasers is that he will personally make certain that the school expels any student pointing a laser anywhere near the eyes of other students.
5040115
Picturing you teasing the gorgonopsids with a laser pointer...
Yes lasers are one of the most common causes of laboratory accidents, and there are dangerous misconceptions. I get nervous when I read posts on forums about things like salvaging a laser diode from a DVD player (not a good idea) with casual comments like 'you just need to get some laser goggles - check ebay' (only use safety goggles from a reputable supplier - yes they are expensive - make sure they block the wavelength and intensity of the laser you are using - there are many different types - and only ever use goggles as a precaution - alreadys have a solid enclosure to make sure the beam and any reflections don't go anywhere near your eye).
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We did not have any accidents. He emphasized safety, plus we only used 5 MilliWatt 650 NanoMeter. Children nowadays can, buy over the Internet, 2-Watt lasers and burnout their eyes while start fires (just need the CreditCardNumber of a parent).
Once an idiot did bring an "orphaned" hatchling of a gorgonopsid onto campus and did have it chase a laserpointer. Everyone kept saying that it might not be orphaned and if it is, one should call a shelter. Then mommy can sniffing the trail of her baby. ¡She was a full grown Inostrancevia!:
Pandemonium ensued . The teachers yelled for all of the students to return to class immediately and lockdown the school. The Inostrancevia Started to tear throw the door. When the teacher found out that Nigel had an Inostrancevia-Cub, she took it from Nigel and gently placed it out the window —— ¡She did not want to make momma any madder by abusing the hatchling!
Mother gently picked up the cub by the scruff of the neck and carried it away. ¡That was an exciting day! For Nigel, the day was not over:
When the Principal found out what Nigel did, he ordered him to the shower (he still had the scent of the hatchling) and burned his clothes. The teacher washed her hands thoroughly.The Principal expelled Nigel and immediately banished him, wearing only a bathrobe and slippers like Arthur Dent, from campus. The Principal had to close the school for a week for a throrogh cleaning to get rid of any lingering scent of the hatchling and told all of us to go home and shower and burn our clothes.
Kids have it so easy nowadays. They would not last 5 minutes in the Permian: