So what exactly is the difference between a flashlight and a laser light? While watching doc use his pointer the other day, I wondered to myself how laser’s actually worked. I later found that unlike regular light, laser light is monochromatic, meaning that it emits only one specific wavelength or color of light (often red), coherent, or all the photons form waves in unison, and directional (highly concentrated and emits light in a beam rather than in all directions). All of these are made possible by the two mirrors (one of which is partially coated so that the laser beams can escape) found at each end of the laser. With these mirrors, only emissions of a specific phase and wavelength traveling perpendicular to the full mirror are reflected back to the partially mirrored surface, where the laser light leaves the tube.
This particular pointer emits wavelengths of 630-680 nm
Shown here is a laser light and its reflection in the mirror, plainly thetai and thetar are the same. We chean also see the images of the two rays in the mirror (where the cross intersects).
(This is late at night in the backyard…using water sprays in order to see the laser being reflected off the drops).
