Currently, green laser pointers are not simple diode lasers but are Diode Pumped Solid State Frequency Doubled (DPSSFD) lasers (this may change in the future, howeverblauwe-violette 1000mw laser pointer ). For a given power, green appears substantially brighter than red wavelengths but are also limited a maximum power of 5 mW. However, since there is a high power IR laser diode inside a green pointer and not all include an adequate IR-blocking filter, there could be other dangers lurking even if the green output is weak or dead.

Keep in mind that obtaining the diode is only a small part of the problem. To drive them reliably, particularly near their maximum power rating, will require a suitable constant current laser diode driver and proper cooling 200mw laser pointer blauw-violet . However, if reasonable precautions are taken and they aren't run near their maximum ratings, actually blowing them out totally isn't nearly as easy as with their low power counterparts.

Beam shape and profile - Whereas the typical conventional low power FP laser diode has an emitting area of 1x3 um (they are all long and narrow because the junction where laser action takes place is almost zero thickness), the shape of the emitting region of a VCSEL can be made whatever is desired for the application - even in the form of a doughnut or ring for optimal coupling to the outer part of a multi-mode optical fiber.

Anyway, it has about the same effect as temperature, with mode hopping that appears. The hops are kind of random with the optical feedback. Globally, the RIN increases. The phenomenon is the most apparent with monomode lasers 700mW laserpen groen . Measures show that multimode lasers have a much more constant RIN with optical feedback. Adding a HF modulation makes the LD to be driven multimode. That's why DVD manufacturers use a modulator. They usually use single mode lasers as they have better characteristics (lower noise, lower lasing threshold).