12 December 2013

The Benefits Of An RGB Laser

By Cornelia White


An RGB laser is that beam source that emits red, green and blue lights in form of laser beams either as a separate beam for each color or a combination of all the three colors in one beam. Through the process of additive color mixing which is achieved through combination of these lights, a number of many other lights can be obtained.

RGB laser sources have proven to perform better than other arc lamps beam sources. While the later are normally cheaper sources of beams, they come with limited lifetime, poor image quality and impossibility of high wall-plug efficiency. This is particularly as a result of poor spatial coherence and availability of less color space, a result of which has seen a rapid rise in their demand.

Beams from these sources are known to be coherent in both wavelengths, both in time and space allowing for inferences. If the change in phase properties is able to take place at the same time over a long distance and at the same period of time, then such waves will produce a very clear image. It is possible to cancel such waves with a similar with opposite phase.

The red, green and blue colors produced by these sources normally have very narrow optical bandwidth making them similar to monochromatic ones. On mixing, the resulting images are normally very clear as other monochromatic sources of beams. It is not surprising that cathode tube displays, printers and even lamp-based beams are now made of them.

These beamers however are known to emit beams that are low in power. With cinema projectors requiring over 10 W of power per color, the use of RGB sources is limited. In addition to power insufficiency, there other challenges include maturity and cost effectiveness. There is also a need of better quality of beam for efficient working of these beamers.

In situations where optical modulators is not practical as a result of low-power miniature devices or for any other reason, the RGB sources are fitted with power-modulators for better signals. Using laser diodes in particular helps achieve modulation bandwidth of tens to hundreds of megahertz or even higher resolutions.

The construction of RGB lasers can be achieved in several manners with the most common ones involving the use of three different lasers with each producing one of the three colors. This method of visible beams however comes with several limitations in comparison to the other methods that employ the use of near infrared rays.

The other method is the use of an infrared solid-state laser where a single near-infrared laser generate a single color that then undergoes through different stages of nonlinear frequency conversion to produce the three colored beams. There are many other schemes of producing the desired wave lengths such as through combination of parametric oscillators, some frequency mixers and even frequency doublers in addition to other methods.

Technological advancements opens windows for development of a better RGB laser that is capable of overcoming most of the challenges associated with the existing ones. With this possibility, these lasers are predicted to replace all other forms of lasers.




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