1, laser wavelength is different. The wavelength of red light is 530 nm, and that of green light is 650 nm. Because of their different wavelengths, the 650nm green laser is brighter than the red light, and the light column is more obvious than the red light.

2. The luminous principle is different. The red laser pen mainly relies on the red laser diode to emit light, which has the simplest structure and can be used as an energy source with only one battery. The green 650nm laser pen uses a nonlinear crystal excited by an infrared laser with a wavelength of 808nm as the light source, which can generate infrared light of 1064nm and generate green light of 532nm after frequency doubling, belonging to a solid-state laser.