Yellow laser pointer
Yellow laser pointers emit at 593.5 nm. Yellow laser pointers are based on the DPSS process,two lasing lines of the ND:YVO4, 1064 nm and 1342 nm, are summed together with a nonlinear crystal. The complexity of this process makes yellow laser pointers inherently unstable and inefficient, with yellow laser pointers outputs ranging from 1 mW to about 10 mW, varying a lot with temperature and usually mode-hopping, if they get too hot or too cold. That is because yellow laser pointers may require temperature stabilizers and active cooling, which can't be mounted into a small sized host. Also, most smaller 593.5 nm pointers work in pulsed mode so they can use smaller and less powerful pumping diodes.
There are:
589 nm yellow laser pointers,
593.5 nm yellow laser pointers,
The new 589 nm bright yellow laser from BeamQ is noticeably brighter, and more "yellow" than the original 593.5 nm Rigel/Vega series yellow lasers. (The 593.5 lasers are often described as "amber-yellow".) This wavelength is closer to the middle of the spectrum, making it brighter to the human eye and more suitable for applications requiring high visibility, long range operation, etc. This is really the brightest yellow pointer. This laser includes the full 5-point safety system as required for Class IIIb lasers in the US and many other countries, and is suggested as an alternative to the regular Rigel HV for customers in these countries who require a 589 nm laser over 5 mW