NOTE – In the first draft of this post, I made an error on my ratio calculations. This has now been rectified. As with all light-based laser/IPL treatments, we require a target (a chromophore) which will absorb the light energy preferentially. In hair, with the visible and near infrared wavelengths that we typically use today,… Continue reading What is the real target in hair when treating with lasers or IPLs?
Month: April 2024
How does fluence relate to depth in the skin?
What is the relationship between fluence at the skin surface and depth into the skin? This is very important. When we fire laser/IPL light energy into the skin, it encounters many, many, many atoms and molecules, which determines how that light will progress and where it will end up. As soon as it hits the… Continue reading How does fluence relate to depth in the skin?
Comparing laser light with IPL light energy in the skin
I often see comments online claiming things like ‘IPL doesn’t penetrate as deeply as laser’ or ‘IPL is ineffective in treating hair/blood/potatoes/whatever…’ These comments are usually never based on the science. So, here’s the science… Light is light! Hope this helps, Mike. Our next MasterClass will be held in Liverpool in June of this year.… Continue reading Comparing laser light with IPL light energy in the skin
Testing the “Neatcell Picosecond Laser Pen” device…
A laser colleague of mine sent me a lovely wee gift – the “Neatcell” pen (thanks Neil!). The company’s web site is here (it’s full of contradictions and discrepancies!!). They claim that this device is a “picosecond laser”. I’m not so sure… Firstly, picosecond lasers are not simple devices. They use a technique called ‘mode-locking’… Continue reading Testing the “Neatcell Picosecond Laser Pen” device…
Why does spot size affect penetration depth?
This is a little tricky because it’s not intuitive. We know, from both clinical tests and computer modelling, that larger spot sizes result in more energy/fluence reaching deeper into the dermis. But how does that happen? Well, it all comes down to scattering. The dermis is mostly composed of collagen fibres. These fibres are all… Continue reading Why does spot size affect penetration depth?
The ‘kill-stun-null’ zones in laser/IPL hair removal – why some treatments don’t work…
Whilst chatting to a young lady about her laser hair removal issues, I thought of a better way to explain why treatments often don’t work. I realised that we need to visualise the skin as a sequence of ‘zones’ – the ‘kill’ zone where the hairs will always be successfuly destroyed; the ‘stun’ zone where… Continue reading The ‘kill-stun-null’ zones in laser/IPL hair removal – why some treatments don’t work…
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