The Powder Toy

m_shinoda

^{680033View Save 680033 Non-PCLN version.Bringing realism to PT!}

Here's an animation to explain the following: http://www.olympusfluoview.com/java/henelasers/index.html

The typical helium-neon laser consists of three components: the laser tube, a high-voltage power supply, and structural packaging. The laser tube consists of a sealed glass tube which contains the laser gas, electrodes, and mirrors. Depending on the power output of the laser, the tube may vary in size from one to several centimeters in diameter, and from five centimeters to several meters in length. The laser gas is a mixture of helium and neon in proportions of between 5:1 and 14:1, respectively. Electrodes, situated near each end of the tube, discharge electricity through the gas. Mirrors, located at each end of the tube, increase efficiency. The power supply provides the high voltages needed (10kV to start laser emission and 1-2kV to maintain it.) The structural packaging consists of mounts for the laser tube and power supply. The laser may also include safety shutters to prevent random exposure and external optics to fine-tune the beam.

The acronym, LASER, stands for Light Amplification by the Stimulated Emission of Radiation. The processes of light amplification and stimulated emission make the helium-neon laser work. Stimulated emission occurs when electricity is discharged into the laser gas. Electrons in the discharge collide with gas atoms imparting energy to them. These energized atoms are left in an unstable state in which some of their electrons have moved to a higher energy level. Excited atoms will quickly return to their ground state as their electrons drop to their normal levels. Each time an electron drops in level, it will emit a photon equal in energy to the difference between the levels. This type of emission is referred to as spontaneous emission. Stimulated emission occurs when a photon of the proper energy strikes an already excited atom, creating an identical photon. These photons will travel through the laser gas causing even more stimulated emission. This ever-increasing reproduction of photons is called light amplification. Using this process, the laser can effectively generate large numbers of photons from relatively few spontaneous emissions. (SIMULATED W/ GLOW IN THIS SAVE)

The amount of radiation that the neon atoms can emit is insufficient to produce a powerful beam without using some form of amplification. Much like a light bulb, the photons in the laser gas travel in random directions making it impossible to create a focused beam. The randomness of the photon paths also makes the laser inefficient because many photons may escape the tube before stimulating further emission. This problem is solved by placing mirrors at either end of the laser tube. Although many photons continue to escape the tube without being productive, those photons that are emitted parallel to the axis between the mirrors will be reflected many times. Each time the photons are reflected through the laser gas, they can cause more photons to be emitted in the same direction. In a short period of time, the dominant direction of emission will be along the axis between the mirrors. In standard configurations, one of the mirrors is totally reflective while the other can transmit 50 percent (USING BMTL TO SIMULATE THAT) of all incident light. The beam is formed by the photons that escape through the partially transparent mirror.

_{I would like to give credits to @Catelite & @therocketeer}

_-M

code1949

@m_shinoda (View Post)
Wow, that's a great concept.

I think you should add a description of the bosonic properties of the atoms that increases their chance of emitting photons when other atoms are also emitting photons.

m_shinoda

680033View Save 680033

Non-PCLN version.

EDIT:

If a laser is continuously emitting light, then there must be power to replenish that lost energy in such a way that the laser action can continue. The power must maintain the necessary population inversion to keep the laser process going, and that implies a pumping mechanism to elevate electrons to that metastable state . The use of helium to "pump" electrons into a metastable state of neon in the helium-neon laser is an example of such a mechanism.

Realistic Laser