White Light Source Spectrum

Almost all of the light is reflected or scattered by the air and water molecules so the snow appears to be the color of sunlight white.

White light source spectrum. The sun is the most obvious. Black and white are a bit different from other colors. Black is the opposite. When white sunlight enters snow very little of the spectrum is absorbed.

However it was the invention of the blue led that led to the creation of new efficient white light sources. The frequency of light that we see as red is being reflected and we see that shirt as red. By scanning changing the measurement beam path length relative to the reference beam a correlogram is generated at each pixel. For example the sun and other stars are sources of white light.

The width of the resulting correlogram is the coherence length which depends strongly on the spectral width of the light source. White light can be generated by a variety of sources both in space and by artificial sources on earth. Sometimes the light bounces around inside the ice crystals before being scattered making the snow seem to sparkle. Figure 1 shows the spds of two electric light sources claimed to be full spectrum the duro test vita lite 5500 fluorescent lamp and ge reveal 60w incandescent lamp as well as daylight at 5500k correlated color temperature cct.

The interference occurs for white light when the path lengths of the measurement beam and the reference beam are nearly matched.