Lasers

How Lasers Work: The Basics

Lasers (Light Amplification by Stimulated Emission of Radiation) have been around for quite awhile now and most people have had the experience of playing with one, even if it has only been a cheap laser pointer you buy at the dollar store. People are always wondering how lasers work. They wonder how such a small item can produce such a powerful light that keeps its composure so well.

The first thing to understand about laser light is that it is only one color. White light has many different colors in it. How does this help? Because when white light hits an object, all those different colors bend in different amounts. Because lasers only have one color in them, the light all bends the same amount when it hits an object. This is what helps to keep the laser lights composure.

So how do you make it only produce one color? Lasers are full of electrons. Whenever you energize an electron more than normal, the electron expands and gives off excess energy. When that excess energy leaks out, it produces a color of light. So, all you do is over-energize a bunch of the right electrons and you have a lot of light that is all one color. Sweet huh!

Once you know this, you can take a material with the right electrons on it and point a powerful light right at it. The electrons in that material will absorb the light and send one color of light right back out, laser light! You can do this with certain mirrors and lenses. This is basically how lasers work.

Although this has only given a basic description of how some kinds of lasers are made, it still is fun to know the basic idea behind such a brilliant piece of technology. Lasers benefit us in so many ways that it can never hurt to know how they work.

Other Kinds of Lasers

Along with the many kinds of lasers presented in this blog, there are a few to put into the miscellaneous file. Here is a list of some other lasers and there basic applications:

Dye Lasers- used for spectroscopy, various kinds of research, birthmark removal, and for separating isotopes. The range of this laser can be tuned by changing the kind of dye used.
Free electron lasers- has various medical uses, atmospheric research, and material science.
Nickel-like samarium lasers- can possibly be used for high resolution microscopy and holography.
Raman lasers- used in creating optical signal amplification for telecommunications etc.
Nuclear pumped lasers- currently being used for research.

If you have been able to read more of this blog, you will know that these are miscellaneous types of lasers. However, each of these lasers can be very useful in the advancement of medicine, communications, and other scientific research.

Kinds of Semi-Conductor Lasers

As you may have noticed from reading this blog, there are so many different kinds of lasers that can be used for various things. Some kinds can be used for the same things as some others. Semi-conductor lasers are also used for some things that other lasers are also used for. However, this does not mean that they are not useful. Each kind of laser is valuable depending on the specific application, even if the general application is the same as another. Here is a list of some semi-conductor lasers and their uses:

Semiconductor laser diode- used for telecommunications, printing, holography, machining, weapons, welding, and pumping from other lasers.
Gallium nitride lasers- used for reading optical discs (playstation).
Aluminium gallium arsenide lasers- used for laser pointers, optical discs, data communications, CD player. Most common kind of laser.
Vertical cavity surface emitting lasers- used in telecommunications.
Quantum cascade lasers- used in research but may be used for things like collision-avoidance radar, industrial process control, and medical diagnostics.
Hybrid silicon lasers- currently used for research.

As you are can see, semi-conductor lasers are heavily used in the world today. Laser pointers are being sold to anyone and are a very common widget to sell for uses in business and personal demonstration.

Kinds of Solid-State Lasers

Out of all the different kinds of lasers out there, there are probably more kinds of solid-state lasers than any of the others. this does not mean that solid-state lasers are the most useful, but it does imply that a lot can be done with this kind of laser. I'm not going to give you a whole lot of information on each kind because there are so many, but I will give you all the names and a very brief application description. As there is much more you can learn about each of these kinds of solid-state lasers, this will at least give you a basic idea of the many different kinds.

Ruby Lasers- used for tattoo removal, and holography. Was invented in 1960 and was the very first visible laser.
Neodymium-doped yttrium aluminium garnet lasers- used in range finding, laser targeting, surgery, pumping other lasers, and research. It is a very common high-powered laser.
Erbium-doped yttrium aluminium garnet lasers- used in dentistry and periodontal scaling.
Neodymium-doped yttrium lithium fluoride lasers- mainly used for pulsed pumping other lasers.
Neodymium-doped yttrium orthovanadate lasers- also used for certain kinds of pulse pumping.
Neodymium-doped yttrium calcium oxoborate laser diode- can be used to simplify the construction of bright green lasers.
Neodymium glass lasers- used in very high powered laser systems (inertial confinement fusion).
Titanium sapphire lasers- used for spectroscopy, light detection and ranging, and other research.
Thulium lasers- used for light detection and ranging.
Ytterbium lasers- used for optical refrigeration, light detection and ranging, processing materials, ultrashort pulse research, and multi-photon microscopy.
Ytterbium-doped glass lasers- used for cutting, welding, marking, fiber optics, and raman laser pumping.
Holmium lasers- used to remove tissue and kidney stones. Also used in dentistry.
Cerium-doped lithium strontium aluminum fluoride- used in light detection and ranging, remote atmospheric sensing, and optics research.
Promethium 147 doped phosphate glass lasers- this laser is radioactive.
Chromium-doped chrysoberyl lasers- used for laser machining, light detection and ranging, and some dermatology uses.
Erbium-doped and erbium ytterbium co-doped glass lasers- used mainly for optical amplification for telecommunications.
Trivalent uranium doped calcium fluoride lasers- not currently in use.
Divalent samarium doped calcium fluoride lasers- also not currently used.
F-center lasers- used in spectroscopy.

Although I might have missed a couple kinds of solid-state lasers in the list above, it still gives you a pretty good idea of the many different kinds of lasers out there and what they are being used for.

Kinds of Metal-Vapor Lasers

There are a few different kinds of metal-vapor lasers. As with many of the other kinds of lasers, these also have important uses that are becoming more evident. Researchers are looking for ways to solve problems in the fields of medicine, science, and many other areas where lasers can come in quite handy. Here is a list of the kinds of metal-vapor lasers and their uses:

Helium cadmium lasers- used a lot for printing purposes. Also used in other scientific research.
Helium mercury lasers- mainly used for scientific research.
Helium selenium lasers- also used primarily for scientific research.
Copper vapor lasers- increasingly being used for dermatology purposes. Also being used for high speed photography, and as a pump for dye lasers.

From this information you should be able to gather that these kinds of lasers are used mainly for scientific research. However, you should also note that they are very valuable lasers for printing, high speed photography, and dermatology applications. Considering the latter three, it can be said that metal-vapor lasers are very useful and a great avenue for scientist to explore further in the future.

Kinds of Chemical Lasers

With all the different categories of lasers that have been discovered it can be confusing to know which ones are for what. We learned in a previous post that the Excimer lasers, which are a kind of gas laser, are used for surgical procedures like laser eye surgery. Chemical lasers, though there are not as many different kinds as there are gas or solid-state lasers, have many important uses also. Here is a list of the different kinds of chemical lasers and their practical uses:

Hydrogen fluoride lasers- mainly being used in research for laser weaponry applications.
Deuterium fluoride lasers- also used as a military weaponry application in various ways.
Chemical oxygen iodine lasers- used as a kind of laser weapon, scientific research, and materials research.

As you can see, chemical lasers are mainly used as a kind of weapon-based defense and offense system for the military because of their abilities to produce very high power ratings and because of their chemical composures. These kinds of lasers help the military stay ahead of their enemies by using more advanced weaponry techniques. These are very dangerous lasers and can only be used with the right knowledge and equipment.

Kinds of Gas Lasers

There are many different kinds of lasers out there. Each different kind has its own practical use. Even the lasers that many people play around with have practical uses, as will be mentioned. I don't want to be too technical, but here is a list of some of the different kinds of gas lasers and their common applications for use:

Helium-neon lasers- this kind of laser is used for things like barcode scanning, alignment, holography, interferometry, spectroscopy, and optical demonstrations.
Argon lasers- used for retinal photo therapy (for diabetes), lithography, confocal microscopy, and for pumping other lasers.
Xenon ion lasers- This kind of laser is mainly used for scientific research.
Krypton lasers- also used for scientific research.
Nitrogen lasers- used for pumping dye lasers, taking air pollution measurements, and for other scientific research.
Carbon dioxide lasers- used for processing material like cutting and welding, and for some kinds of surgeries.
Carbon monoxide lasers- also used for processing certain materials, and for photoacoustic spectroscopy.
Excimer lasers- used for laser surgeries such as laser eye surgery, or lasik surgery, and for ultraviolet lithography.

Lasers have helped us in so many ways that it is a technology that cannot be ignored. Scientists are constantly research other kinds of lasers and more variations of how to use them in a beneficial way.