What is a laser you may be asking yourself
Understandable, but I will tell you about them regardless
Laser is an acronym for Light Amplification by Stimulated Emission of Radiation.
There are many variations of lasers but all have the same core parts. Those Parts are a medium, two mirrors, and an energy source. Energy from the power source excites the electrons in the medium. The excited electrons produce photons of light. There are two mirrors facing each other in a laser. One of the mirrors is completely reflective, the other is only partially reflective. The photons bounce back and forth twixt the mirrors. As a photon hits one of the mirror, it splits and also helps stimulate other electrons. This is called the gain. Naturally however, energy is lost and not all the photons make it to the other mirror. This is called the loss. As long as the gain outnumbers the loss, photons will continue to go through the partially reflective mirror, and those photons is what you see coming out of the lasers.
There are many different kinds of mediums for lasers. There are dye lasers, gas lasers, crystal lasers and more.
Also, you can have a lot of fun with laser pointers and diffraction gratings. If I figured out how to post videos on here, I would put a video, but alas, I cannot, so I implore you to explore the mystical youtube in pursuit of cool laser videos. They aren't hard to find.