How lasers work
Lasers are used everywhere from the dentist’s office to sci-Fi movies. But how do they work? Why laser pointers are so different from a regular flashlight? Why laser, you can create a devastating weapon? And why laser swords not so dangerous as their steel counterparts? Let’s talk about the nature of the laser, and let’s hope that after reading you get smarter.
Lasers — that’s the kind of routine that still wonder. They are used every day in dentistry, tattoo parlors, printing and playback on CD players (remember them?). But they also pop up in science fiction films, hitting us with a view of the laser swords or laser blasters. We always expected from them something new. I hope that there will be new type weapons and everyone will be like, «pow-pow-pow!». But what do we actually know about lasers? It is believed that the laser is a form light. But this is not true. It has the property of monochromaticity and coherence, which allow the use of laser technology in unique cases. Conventional light bulbs and lanterns noticeable lose of lasers on the field of battle.
The structure of the atom
To understand how lasers work, we must first look at the atom. Everything you interact with: the chair on which I sit, the air you breathe, even our bodies — everything is made of small particles called atoms. If you look at the periodic table of elements, we see about a hundred different types of atoms that exist today. The different materials consist of different combinations of these elements.
Each atom contains a nucleus (consisting of protons and neutrons) and a set of electrons which are constantly in motion orbiting around the nucleus. Atoms have a constant energy that does not require recharging. Electrons that are closer to the nucleus, can be subjected to stimulation that will lead to the «initiated» state of the atom (sounds like erotic 70’s, but it’s physics).
Thanks to quantum mechanics we know that a atom can not travel in discrete, well-defined orbit. But if you take energy in the form of light or heat, it can easily be transformed into a higher energy state. When these excited electrons decide to relax, they can reunite with their neighbors in the lower energy levels of the atom to produce energy in the form of photons and light rays. The difference between the initial and final orbit of the electron determines the energy of the released photon, which, in turn, will determine the wavelength and colour of light emitted.What is a laser and how does it work?
If you’re not sitting at the last Desk on the lessons of physics, we must remember that the word «laser» is an acronym that stands for «light amplification through stimulated emission of radiation». The key word in that transcript is «forced». This distinguishes lasers from the more simple forms of light. When you turn an ordinary flashlight, the light passed through the random paths in all directions, with the result that he scatters and becomes relatively weak. And now we take a laser, whose light is «forced» and «coherent» photons move in unison and in one direction. The result is a narrower but more intense beam of light.
But how to get the photons to observe such strict rules?
Let’s get back to our picture of the atom. When an electron moves from the excited energy state to a dormant state, the released photon has a certain amount of energy. The photon energy equal to the difference between energies of the ground and excited States of an atom. If the recently released photon collides with another electron which is in the same excited energy state, it (the electron) acquires the properties of a photon is its energy (color) and phase (relative position).
If you have a sufficient number of electrons in the excited state, the first photon can start a chain reaction of stimulated emission. If photons will increase, electrons will begin to move back into their normal energy state than it will release new photons, which, in turn, stimulate to throw more photons. In the end, this emitted light will have a constant energy and a constant wavelength. The world of such a wave is called monochromatic.
That is, a chain reaction of photons — this is what lasers work. The pumped electrons occurs via powerful flashes of light or electrical pulse. As soon as the first photons are released outward, the lasers, the two mirrors reflect the photons stimulates the movement of light back and forth through the body. In General, the laser is a real Orgy of photons.
Laser reference stars
Focused lasers makes them ideal cutting tools when you need accurate, straight lines. This requirement often comes into play when it comes to the human body, the slice of the cornea to improve vision, tattoo removal or correction of chipped teeth.
However, the coolest use of a laser, we observe in astronomy. When astronomers look at a distant object, e.g. a star through a telescope, the light that we see is distorted, passing through the turbulent atmosphere of the Earth. Sometimes the information is so difficult to decipher that it is impossible to determine whether the distortion property of the star or is it just the effect of watching through the earth’s atmosphere.
One way to circumvent this problem is the technique of adaptive optics: astronomers observing the object of study, and at the same time, there is a very bright object, usually the nearest star. Because scientists already know what to expect from the object of comparison, they look at the image that they see, except for atmospheric errors. The obtained atmospheric model is then used to adapt the optics of the telescope in real time to compensate for the effect of the atmosphere when observing the target.But this method has a big problem. Not always at hand is nice and bright, the object of comparison. When in the sky there is nothing suitable, astronomers create their own «star» using a laser beam that is launched straight up into the sky. That is, today, scientists can create a laser guide star in any place where it is needed. Just imagine this is much steeper than any of the lightsaber, isn’t it?
According to the materials of Dr. Sabrina Stierwalt