A laser pointer is laser shaped like a pen that is designed to be portable and hand held. Laser pointers were originally used to project a dot or point from the beam that can be used to point out items or objects to an audience such as during a presentation. With their increased proliferation and power, the application of laser pointers has grown to encompass uses such as astronomy, construction, light shows and entertainment just to mention a few.
Most laser pointers will have a power of one millawatt or less and will not have a beam that is visible in daylight or well lit environment. The light from these lasers will only be visible when the light hits a reflective surface. Laser pointers with 35mW or more in power will have a beam that is clearly visible in daylight or well lit environment.
Green and Red Lasers
A red laser is any laser that emits light with a wavelength in the red spectral region which is approximately 620nm to 750nm. Typical wavelengths emitted by red lasers are 635nm (ruby red), 650nm (lighter red/orange) and 670nm.
Green lasers on the other hand are lasers that emit light with a wavelength in the green spectral region from 495nm to 570nm. The typical wavelength for green lasers is 532nm (emerald green).
Red versus Green laser pointers
The most obvious difference between green and red laser pointers is beam visibility. The human eye is most sensitive to light with a wavelength of approximately 555nm (yellow/green) which makes green lasers much more visible than red lasers. Green laser can appear to be roughly 50 times brighter than red lasers.
The other main difference between red and green lasers is the complexity of their construction. In simple terms a red laser consists of a circuit board, red laser diode and a focusing lens. Green lasers on the other hand are much more complex because there are no green laser diodes that can be used. Instead an infrared (808nm) diode is used with a combination of special crystals and a filter to produce green laser light.
Examples of other types of Green and Red lasers
Red lasers
-red gas lasers – for example Helium-neon (HeNe) and krypton lasers
-Titanium-sapphire lasers – these lasers mostly emit in the infrared spectrum but can be tuned down to 650nm.
-Praseodynium doped unconversion lasers – emit light with a wavelength of around 635nm
-frequency doubled lasers – apply the phenomenon of using an input wave to generate a wave with twice the optical frequency. Also called second harmonic generation lasers
Green lasers
- Argon lasers – the highest power for an argon laser can be obtained at 514.5nm. Can acheive over 20 W but energy efficiency is very poor.
-Helium neon lasers – several milliwats at 543.5nm
-Copper vapor lasers – comparatively higher powers at 510.6nm
-Erbium doped upconversion lasers- are around 550nm and normally have an output of tens of milliwatts
-Dye lasers – can be tuned to operate in the green spectral region.
Red Laser Trivia : Red lasers and Blue lasers in Dvd’s
Even though blue lasers have taken the DVD world by storm with vastly superior memory storage etc, red lasers will not be completely phased out. Research on carried out at the end of 2005 on the comparison of blue and red lasers in DVD’s had the following interesting results
-blue lasers were shown to have no significant gain in accuracy over red lasers
-blue lasers are approximately 10 times more expensive than red lasers
-red lasers are longer lasting and more durable than blue lasers
» left by Salad from KSA (2 years 143 days ago.)
helpful... but were are the references Respond to this comment
» left by Luke Skywalker from United Kingdom (1 year 275 days ago.)
FYI: The very same brand of these lasers are sold at TECHLASERS, they're the cheapest resellers online at the moment beating out other resellers and they ship lighting fast too with UPS. Respond to this comment
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Article added to SearchWarp.com on 3/23/2007 3:58:24 AM. View other articles written byRobert Galagas(836)
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