Colonial Millworks and the Physics of a Laser

Today we visited Colonial Millworks in Beverly, West Virginia.  This plant focused its energy on floor mouldings and cabinet mouldings.  Though the plant revealed many physics concepts we will encounter in class, there was one concept that caught my attention more so than the traditional mechanics applications we would typically discuss - LASER.  Yes friends, the plant incorporates lasers at various saw-stations for alignment in the process of making the most accurate cut.  But, what really is a laser?

LASER is an acronym which stands for Light Amplification by Stimulated Emmission of Radiation.  If an atom absorbs energy it will enter an excited state.  The atom, however is like most thinks in nature and desperatly wants to stay in comfortable equilibrium and so return to its natural ground state.  To do this, it will emmit light energy in the form of a photon. We should remember from chemistry that the energy of a photon is equal to Planck's Contant times the frequency of the photon:  E = hv.  A laser plays on this emmission of energy.

Stimulated emmission of a photon is the essence of what we "see" as a laser.  When an emmitted photon strikes an atom in an excited state (absorbed energy) two photons can be released to strike two more excited atoms.  This process can continue to grow and replicate itself.  It is important to note that these photons are all in phase; they have the same wavelength and frequency causing a large amplification of the light/radiation, and now we have a laser.  Since they do have the same wavelength and frequency the laser appears monochromatic or of only one color; this will usually be red or green like the lasers seen at Colonial Mills. 

A point of interest is the timing of this blog post.  I just received an email last night from a friend who pointed me to a story where at Lawrence Livermoore a new laser generated 500 terawatts which would be about 1000 times more power than the entire US would use at any given moment.  It also generated 1.85 megajoules of enegy; this is 100 times more than any previous laser. The scientist are attempting to use the laser to master clean nuclear fusion which would solve all future energy problems; it takes an enormous amount of energy to overcome the repulsive force between positive nuclei.

So, from trying to solve our dependency on fossil fuels, to making sure your cabinets line up correctly, physics is constantly changing the world in which we live.  Can you think of any other applications of a laser?  I think you will be surprised just how dependent we are on Light Amplification by Stimulated Emmission of Radiation.