Laser Power Supply

Written by Kevin Tavolaro
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A laser power supply is a device that uses laser diodes to generate energy. Laser diodes function like a domino chain, only they maintain consistent momentum. A laser diode is marked with holes on the top half, corresponding to holes on the bottom half. Electrons are fired from the diodes, and when they fall into these holes, a chain reaction begins. When the electron falls into the hole, it radioactively recombines with the hole itself, emitting a small photon. If a photon of precisely the right size is generated, this instigates another electron to launch itself into a hole, which, in turn, generates yet another photon of the same exact size. This consistent cycle can be calculated to run at any number of speeds or strengths, depending on the size and placement of the diode.

A laser diode is typically very thin, and is always shaped like a cleaved rectangle. The two ends of the diode are aligned with each other, and feature smooth, reflective edges. As the photon is emitted inside the diode, it is caught between these mirrored edges, which amplifies the light back and forth several times, quickly rising and falling in intensity. When this occurs, and the amount of loss is exceeded by the amount of amplification, the diode begins to emit energy. This is known as the "laser" state.

Heterostructure vs. Homojunction Laser Power Supply

The original laser power supply was known as the homojunction diode, a simple variation on the dual reflective device described above. The simplistic design of the homojuncture diode makes it an inefficient choice for most tasks, as the amount of energy needed to generate the initial pulse rivals that of the final output. This makes the homojuncture diode an extremely unstable, unreliable choice in most situations. The size of the pulse is also likely to cause the power supply to burn out rather quickly, as well.

A more recent, and efficient laser power supply is the double heterostructure laser diode. This device operates much like the process noted above, but contains an additional component. A paper-thin middle layer is inserted between the two halves of the diode, serving to prevent excessive dissipation. As electrons pass through this middle layer, they are quantised, boosting the overall amplification and efficiency.


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