change a cheap laser pointer color?

I got a cheap laser from the shop. here is it : http://www.scitoyscatalog.com/Merchant2/graphics/00000001/small_5_head_laser_pointer.jpg

It is red. Is there a way i can make it green, blue, purple, yellow ,etc. ?

and another one: How can I focus a led on a single spot to be like a laser?

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You can't change the colour of a laser, its whole "laserness" is based on the fact its a single colour. White light lasers are possible, but they use different methods than laser pointers, and they are fiendishly expensive.

Steve

This is actually quite wrong. For another experiment just for fun, take a green laser and shine it through extra virgin olive oil. The result will shock you completely!

No, what you observe there is green light interacting with the medium and fluorescing.

No, you are wrong again. Research what's actually happening when the green beam turns red.

netbus (author)  steveastrouk7 years ago
how bout using a LED as a laser diode? can i focus it on a single place to have a dot like on a laser?
You might focus it to a reasonable dot projected on a surfave, but you can't focus it to a bright, laser like, beam.

Steve

Actually, those nice green lasers you may see are actually pumped by an infra-red laser diode. These are referred to as DPSS or double pumped solid state.

  1. The 808nm infrared light from the laser diode is used to pump a Neodymium doped Yttrium Orthvanadate or Nd:YVO4 crystal which produces light with a wavelength of 1064nm.
  2. The 1064nm wavelength light is then frequency doubled through a Potassium Titanium Oxide Phosphate (KTiOPO4) or KTP crystal. By doubling the laser frequency, you cut the laser wavelength in half producing a 532nm green laser light.

Generally speaking, DPSS green lasers are approximately 20% - 30% efficient. That is, a green DPSS lasers using a 200mW 808nm pump diode should produce a 40mW to 60mW 532nm green laser pointer. However, as there are various lenses and filters (such as an infrared or IR filter) involved in the process of producing green light, the efficiency level is sometimes less. The efficiency depends on the quality of crystals and lenses used in the laser pointer.

Blue DPSS lasers actually use a similar process. The infrared 808 nm laser diode is used to pump a Neodymium Yttrium Vanadium Oxide or Nd:YVO4 crystal. The outcome is an infrared light with a wavelength of 946nm. This 946nm light is then frequency doubled via a Lanthanum Boron Oxide or LBO crystal to produce a 473nm blue laser. As the efficiency for blue lasers is only around 3%-5%, blue laser pointers are relatively weak in power.

Dude your aargument music to my ears. People like you step it up !

This is also the reason that a green laser of 200-300mW costs the same as a 1 - 1.5W infra-red laser - the diode for both is the same. One simply has the crystal that changes the colour, but you only get 20-30% efficiency. So you get the colour change, but at a high cost to the power. Oddly though, from a purely visual point of view, a green laser at 200mW seems much brighter at a far greater distance than a 200mW red laser or blue laser etc.

I should also clarify that blue "DPSS" lasers are weak in power.

Actual blue lasers are quite powerful. I have a couple 1.6W blue laser pointers, and I can light a cigarette from across the room!

BradenT1 year ago

Yes. you CAN sort of "change" its color. *if you have something that can poke a VERY tiny hole.

Tesla boy7 years ago
You can try this laser build at http://www.rog8811.com/whitelaserpointer.htm then you should be able to split the beam into colors with a prism and have lots of multi-colired beams.
J3x7 years ago
Price: $11.73... ???

U payed THAT much???

i can get a 5mW red lazer pen for 99 cents.

sorry to ruin the party, but its probally cheaper to buy one off ebay..>.>
kiffer3607 years ago
My understanding (correct me if Im wrong) is that each laser emits only one narrow frequency of light, most commonly red, as that is the lowest power. As you go up the spectrum, the emitted energy increases as the wavelength of light does. Conversely, the power draw is higher. Anyway, the simplest answer I can give you is, you need to get a probably colored laser. Red lasers are most common, followed by green, then blue, up the spectrum. Normal light contains all these wavelengths, and thus appears white. Not sure about this, but I believe that different materials lase at different wavelengths. Once again, I am unsure about most of this, so don't take me to seriously ;) 
just put a colored peice of paper in front of it...a