The 593.5nm yellow laser beam has only recently been developed in the form of hand held portable lasers. This is the newest addition to the world of laser technology and is quickly becoming one of the most popular. Whether for science education, astronomy, or even military use, yellow laser pointers are finding themselves shining the world over. Be the first person you know with a yellow laser gadget that is truly tantalizing.

Here's some tip about how to generate a rare 593.5nm  Yellow Laser Pointer:

In a 593.5nm yellow pointer, there's a BIG infrared laser diode that generates laser light at 808nm, this is fired into a crystal containing the rare-earth element neodymium. This crystal takes the 808nm infrared laser light and lasers at 1,064 and 1,342nm (yes, deeper in the infrared!). This laser light comes out of the NdYV04 (neodymium yttrium vanadium oxide) crystal and is then shot into a second crystal (containing potassium, titanium, & phosphorus, usually called KTP) that roughly doubles the frequency to 593.5nm - the bright orangish yellow color you see. This light is then collimated (focused) by a lens and emerges out the laser's business end. Just before the lens, there's a filter that removes any stray IR (infrared) rays from the pump diode and the neodymium crystal. You don't want that stuff in your yellow beam, trust me. :-)

This is why Yellow diode lasers are so much more expensive than red ones. Lots of itty bitty parts, and they all need to be very carefully aligned by hand. If the polarisation is off, one or both crystals need to be turned. With red diode lasers, you just slap in the diode and slap a lens in front of it.

Caution:

Staring directly at the aperture of a working strong laser pointer can temporarily or permanently damage your eyes.

• DO NOT look into the aperture of the laser when inserting batteries.
• ALWAYS point the laser away from eyes.
• NEVER stare directly at the laser beam.
• Keep it OUT OF REACH of children.
• ALWAYS use the laser at duty of 60 seconds ON / 10 seconds OFF. NO cooling system is installed. It is NOT designed for long time consistent emission use. Constantly staying at ON mode will result in accumulation of the heat & sacrifice the lifetime of laser diode.
• MUST be handled with care.
• This laser pointer is SAFE to the human body ＆ the environment under normal operation and proper use.
• Laser Fanatics suggest to use Laser Glasses for every laser pointer more than 5mW.