Laser Color Visibility

The human eye can see light in the visible spectrum ranging from Red to Violet, i.e. the colours of the rainbow. The eye's sensitivity is non linear, so different colours are perceived at different intensities to the eye. So for the same given power, a 100mW Red laser will appear much dimmer than a 100mw Green laser.The colour the human eye is most sensitive to is a shade of Green which has a wavelength of 555nm.

Wavelength	Response	Color	Typical Source/Application
350 nm	0.00001	UV
380 nm	0.0002	Near UV
400 nm	0.0028	Border UV	Nichia violet GaN laser diode
410 nm	0.0074	Border UV	Nichia violet GaN laser diode
420 nm	0.0175	Violet
442 nm	0.0398	Violet-blue	Violet-blue line of HeCd laser
450 nm	0.0468	Blue
457.5 nm	0.0556	Blue	Blue frequency doubled Nd:YVO
457.9 nm	0.0562	Blue	Blue line of argon ion lase
473 nm	0.104	Blue	Blue frequency doubled Nd:YAG
488 nm	0.191	Green-blue	Green-blue line of argon ion laser
500 nm	0.323	Blue-green
510 nm	0.503	Green	Emerald green line of copper vapor laser
514.5 nm	0.588	Green	Green line of argon ion laser
532 nm	0.885	Green	Green frequency doubled Nd:YAG or Nd:YVO
543.5 nm	0.974	Green	Green HeNe lase
550 nm	0.995	Yellow-green
555 nm	1.000	Yellow-green	Reference (peak) wavelength
567 nm	0.969	Yellow-green	Green line of Helium-Mercury laser
568 nm	0.964	Yellow-green	Y-G line of some krypton ion lasers
578 nm	0.889	Yellow	Gold line of copper vapor laser
580 nm	0.870	Yellow
594.1 nm	0.706	Orange-yellow	Yellow HeNe laser
600 nm	0.631	Orange
611.9 nm	0.479	Red-orange	Orange HeNe laser
615 nm	0.441	Red-orange	Orange line of Helium-Mercury laser
627 nm	0.298	Red-orange	Orange line of Gold Vapor Laser
632.8 nm	0.237	Orange-red	Red HeNe laser
635 nm	0.217	Orange-red	Laser diode (DVD, newer laser pointers)
640 nm	0.175	Orange-red	Laser diode (DVD, newer laser pointers)
645 nm	0.138	Orange-red	Laser diode (DVD, newer laser pointers)
647.1 nm	0.125	Red	Red line of krypton or Ar/Kr ion laser
650 nm	0.107	Red	Laser diode (DVD, newer laser pointers)
655 nm	0.082	Red	Laser diode
660 nm	0.061	Red	Laser diode
670 nm	0.032	Red	Laser diode (UPC scanners, old pointers)
680 nm	0.017	Red
685 nm	0.0119	Deep red
690 nm	0.0082	Deep red
694.3 nm	0.006	Deep red	Ruby laser
700 nm	0.0041	Border IR
750 nm	0.00012	Near IR
780 nm	0.000015	Near IR	CD player/CDROM/LaserDisc laser diode
800 nm	3.7*(10)-6	Near IR	Laser diodes for pumping Nd:YAG, Nd:YVO
850 nm	1.1*(10)-7	Near IR	Laser diodes for pumping Nd:YAG, Nd:YVO
900 nm	3.2*(10)-9	Near IR	Laser diodes for pumping Nd:YAG, Nd:YVO
1,064 nm	3*(10)-14	Near IR	Nd lasers (including YAG)
1,523 nm	0.0000	Near IR	IR HeNe laser
3,390 nm	0.0000	Mid-IR	IR HeNe laser
10,600 nm	0.0000	Far-IR	CO2 laser

The DPSS Lasers of 532nm is very close to the peak of the eye's sensitivity. The human eye is most sensitive to the color green. Therefore, green laser pointers actually stand out in brightness compared to all other visible lasers including red, blue,violet and yellow laser pointers. The greens and blues produced by a typical argon are further away from the peak response of the eye, so they appear to be dimmer in comparison. This is why DPSS laser are said to be 3 to 4 times brighter than a typical argon laser. So a 100mW DPSS laser will look the equivalent to a 300mw argon laser in terms of apparent brightness.

Taking this to an extreme, if you were to compare a 100mw 532nm Diode laser with a 2W Infrared Laser e.g. emitting 1064nm, the 100mW laser will look much brighter because the human eye can't see infrared wavelengths!