Thick and thin hair – how much light energy do they actually absorb during photothermal treatments?

How thick is a hair? Well, according to some research by physicist, Brian Ley (they do all the best research!!!), it ranges between 17 and 181 microns in diameter (see his results here). That is between 0.017 and 0.18 mm. So, that means that their cross-sectional areas [A = pi x (radius)2] are between 0.0000023 and 0.00026 square… Continue reading Thick and thin hair – how much light energy do they actually absorb during photothermal treatments?

Laser Tattoo Removal – wavelengths and anisotropy

I’ve just made a couple of little animations looking at the differences between the laser wavelengths we use for tattoo removal and how anisotropy comes into play. You might be surprised at what actually happens in the skin. Anisotropy is rarely discussed in the laser tattoo world, yet it has significant effects on treatment outcomes.… Continue reading Laser Tattoo Removal – wavelengths and anisotropy

Light penetration into skin and the subsequent temperature rise

Where does light go when it enters the skin? Well, it’s actually quite complicated! Some of it reflects off the skin surface, some is absorbed in the melanin (basal layer), some penetrates through to the fatty tissue, while some is turned around and escapes back into the air. The follow slideshow gives a simple explanation… Continue reading Light penetration into skin and the subsequent temperature rise