We all know that infrared laser diodes are widely used in daily life, so do you know which one is brighter, the 100mw product or the 200mw product, in the same wave band?

On the premise of the same wavelength band, the same divergence angle and the same optical design, the infrared laser diode of 200mW is indeed brighter than that of 100mW, and its energy output is doubled. But if you look at it with the naked eye, the difference may not be as big as you think, and sometimes you can hardly see it.

First of all, infrared itself is "invisible"

The general wavelengths of infrared laser diodes are 780nm, 808nm, 850nm and 940nm, and the sensitivity of human eyes to this band is very low. Especially after 850nm, it is almost invisible to the naked eye, and only a little reddish or a little dark spots can be seen.

Divergence angle and optical design have greater influence.

Sometimes, two infrared laser diodes with the same power look very different in brightness, which is actually caused by different optical structures.

Brightness ≠ power

Brightness is the intensity of light perceived by human eyes, while power is the energy output. For the infrared band, the reference significance of brightness is not significant. For example, if you take a 940nm 200mW laser, it is almost invisible to the naked eye, but it is a white light when you shoot it with an infrared camera.

If you are doing night vision, sensing, ranging and optical communication-200mW is more suitable, with stronger signal and longer detection distance, but you must do a good job of heat dissipation.

If it is only a general indication, calibration and low-power light source, 100mW is enough and its life is longer.