(L) light (A) Amplification (S) Stimulated by the (E) Emission of (R) Radiation
In a laser, usually intense flashes of light or electrical discharges pump what is called the ‘lasing medium’. The lasing medium now contains an assortment of atoms with some electrons in excited states. These excited electrons have much higher energies than the other electrons. When the excited electrons release there energy they move down to a lower state. This energy is emitted as photons.
The photons each have a wavelength that is determined when the photon is released which was the state of the electron’s energy.
Then two mirrors are placed between the photons, one of the mirrors is “half silvered”. The pair of mirrors is placed at each end of the active medium. The photons with a specific wavelength and phase will reflect off the mirrors and go back and forth. Throughout this process they stimulate other electrons and cause the emission of more similar photons. The “half silvered” mirror means that it reflects some of the light and lets some light through. The light that is let through is the laser light.
Then two mirrors are placed between the photons, one of the mirrors is “half silvered”. The pair of mirrors is placed at each end of the active medium. The photons with a specific wavelength and phase will reflect off the mirrors and go back and forth. Throughout this process they stimulate other electrons and cause the emission of more similar photons. The “half silvered” mirror means that it reflects some of the light and lets some light through. The light that is let through is the laser light.