Introduction to Laser Optics Lab

Hi, my name is Stefaan Vandendriessche, laser optics product line manager at Edmund Optics. In this video series we'll take an in-depth look at laser optics concepts. From specifications to coding technologies to product types. Lasers are used in a wide variety of applications from laser materials processing, to medical equipment for sensing, to entertainment. Laser is an acronym that stands for light amplification by stimulated emission of radiation. In the most simplified case electrons are found in specific energy levels of an atom including energy level one or the ground state, energy level two or the first excited state and energy level three or the second excited state. When these electrons in the ground state are excited they jump up to the excited states. However, they will not stay in these excited states for long. As the electron decays back to a lower state a photon is emitted with the energy of the difference between the excited and the ground state. This process is called spontaneous emission. Some light sources such as light bulbs rely on spontaneous emission, lasers on the other hand rely on a special form of mission called stimulated emission. When a photon with the same energy passes by an excited electron in the right conditions it can force the electron to drop back to the ground level, creating a second photon the same direction, phase and energy. This is called stimulated emission and is reflected in the laser acronym. In order for a laser to function efficiently there needs to be very many electrons in the excited state so they can be stimulated back down. However, electrons prefer to stay in the ground state and once excited will try to return back to the ground state. For a laser to function efficiently the number of particles in the excited States needs to exceed the number of electrons in the ground state, called population inversion. This is normally not allowed by the rules of quantum physics, in order to circumvent this requirement a second excited state is necessary. Electrons are excited to the second state and then relax back to the first excited state. This allows population inversion to occur and the laser to lays. The gain medium is a material that contains these energy levels. Lasers are typically classified by their gain medium. Gas lasers use gaseous medium inside the laser cavity. Solid-state lasers like Ruby or neodymium YAG utilize a crystalline glass medium and diode lasers are electrically pumped semiconductor mediums. To learn more about the properties of lasers watch the next video in the series.