Monday 30 December 2013

The Working Of An RGB Laser

By Cornelia White


A laser that emits three primary colors, red, green and blue is an RGB laser, the name coming from the three primary colors. These can be emitted in a single beam for all the three colors or a separate beam for each of the color. Through additive mixing which involves combination of the three basic colors at different frequencies, a number of several other colors can be obtained.

Arc lamp sources are now being replaced with RGB lasers for light emissions, particularly given that they are much better when it comes to performance as compared to the arc lamp beamers. Arc lamp beamers are known to be the cheaper alternatives but they have limited lifetime, poor image quality and impossibility to achieve high wall-plug efficiency.

These types of lasers achieve coherence of wavelengths, a reason why they outperform many other sources of beams. The coherence is on both time and space allowing for inferences. The consistency in the change of phase properties over a long distance results into high quality images that make them preferred for entertainment and other professional applications.

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.

RGB sources however suffer from a major setback given that the power level that is emitted is usually of low level. Most cinema projectors for instance require up to 10 W per color or even more. This level of power sufficiency, maturity or even cost effectiveness is still beyond the existing RGB scanners. When it comes to beam quality, these machines have to operate with high quality beams for them to perform effectively.

This are at times fitted with power-modulators particularly in the instances where the use of optical modulators is not practical due to low-power miniature devices. This is done to achieve better signals and laser diodes are used in most of the occasions. These particular diodes help achieve increased bandwidth to tens or hundreds of megahertz which in turns significantly improves resolutions.

The red, green and blue lasers come in several types depending on the design and construction. One method involves the use of three different types of lasers with each emitting beam of a particular color. These forms of visible beam lasers are however not as suitable as the non visible ones that are near infrared in nature.

The use of infrared solid-state lasers involves application of a single laser that emits a beam of near infrared (invisible) nature. Such a beam then undergoes through several stages of nonlinear frequency conversion the end of which a three colored beam is produced. The other methods that have also been used to obtain these colors are the combination of parametric oscillators, the use of frequency doublers and the use of frequency mixers.

With the technological advancement, better performing RGB laser machines are being produced. With the current attempt to introduce the fourth color in this type of laser, something that will even improve their performers for the better. The expert prediction is that these forms of lasers will be replacing the other forms of beamers.




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