The depth of light penetration is influenced by the coherence, collation, and intensity of the light beams.

“the exact depth that's reached by the red light or the near infrared is is kind of a function of — how the how the light beams are organized so — what is the amount of coherence which is how much do the wavelengths line up with each other so if if the wavelengths are all coherent in the exact same — — the Peaks and valleys are in the same place it's going to have more penetrant and and then what's the extent to which they're all aligned in the exact same direction — that's called collation so in other words the light isn't spreading but rather it's all pointed”