Where do photons go in the skin?

When photons (light) enter the skin they can undergo only two processes – absorption or scattering. Once a photon is absorbed, its energy is ‘gained’ by the absorbing site. This may be a melanosome in the epidermal basal layer (see figure 1 – ‘Epidermal absorption’). This absorption will transfer the photon’s energy into the melanin… Continue reading Where do photons go in the skin?

How can there be more fluence inside the skin than is applied at the surface???

Here’s a strange thing…. When we fire a laser or an IPL at the skin surface we usually know the fluence that is applied. So, we figure that a 10 J/cm2 will penetrate into the skin and diminish with depth. Well, bizarrely, it doesn’t!! This is entirely due to scattering. So, what is scattering? The… Continue reading How can there be more fluence inside the skin than is applied at the surface???

MasterClass – Birmingham – Sept 2022 – Details

The 1st DermaLase MasterClass wil be held in September this year in Birmingham. The detals of this event can be downloaded in a pdf format from here. Here is an outline of the topics which will be discussed – if you have a particular topic which you wish to be addressed, please let us know.… Continue reading MasterClass – Birmingham – Sept 2022 – Details

How strongly are different laser wavelengths absorbed in melanin and blood?

These days we use a wide variety of lasers and IPLs to treat various targets in the skin. Two major targets are hair and blood vessels. But how much of the laser/IPL light is actually absorbed by these targets? Using data from two very clever scientists (Steve Jacques and Scott Prahl) it is relatively easy… Continue reading How strongly are different laser wavelengths absorbed in melanin and blood?

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?

Back-scattered light from the skin is much more than we think…

My Letter describing back-scattered laser radiation from the skin has been published in the ‘open market’ by Springer! I’m very pleased that they have done this. However, I am now thinking that the levels of back-scattered light are higher than I first thought. The is coming from new work I have been doing looking at… Continue reading Back-scattered light from the skin is much more than we think…

Back-scattered light from the skin is much more than we think…

My Letter describing back-scattered laser radiation from the skin has been published in the ‘open market’ by Springer! I’m very pleased that they have done this. However, I am now thinking that the levels of back-scattered light are higher than I first thought. The is coming from new work I have been doing looking at… Continue reading Back-scattered light from the skin is much more than we think…