http://www.laserfest.org/lasers/how/ruby.cfm

http://www.hk-phy.org/articles/laser/laser_e.html

https://en.wikipedia.org/wiki/Laser#/media/File:Laser.svg

https://gifer.com/en/1tyM

Audio : http://tones.wolfram.com/generate/G10fQ25mXD5csiKyNC272HTOtzQNUz1fWv3h1fbIzUV9xiqu

“How lasers are used in the Movies ” – https://www.shapecut.com.au/blog/how-lasers-are-used-in-the-movies/

‘The History of the Laser, A Trip through the Light” – https://www.photonics.com/Articles/A_History_of_the_Laser_A_Trip_Through_the_Light/a42279