Laser fluence and skin colour – how do we choose the correct fluence for the removal of hair, vessels etc?

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To answer this question, we need to understand what is going on in the skin… When light (any type) enters the skin, it encounters atoms and molecules – lots of them! As a direct consequence, the photons are scattered – their directions change. Some of them are scattered so much that they leave the skin… Continue reading Laser fluence and skin colour – how do we choose the correct fluence for the removal of hair, vessels etc?

Why are Nd:YAG and Alexandrite lasers ‘easier’ to use in hair removal?

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In hair removal procedures, most long-pulsed Nd:YAG and Alexandrites lasers typically use short pulsewidths – usually less than 10ms, often less than 5ms. They can deliver all of their energy within these short pulses, whereas diode lasers and IPLs typically use longer pulses.  Such short pulses induce higher temperatures in the absorbing targets in the skin,… Continue reading Why are Nd:YAG and Alexandrite lasers ‘easier’ to use in hair removal?

What you MUST know when applying lasers or IPLs to the skin.

Posted in Lasers and IPLs - hair & vascular & pigmented lesions, Other sciencey stuff1 Comment

People often ask my advice on treatments which don’t appear to have worked too well. Either there’s too little reaction in each session or no result after a number of repeat sessions. They don’t know why and turn to me for help. I am always happy to help where possible but to do so, I… Continue reading What you MUST know when applying lasers or IPLs to the skin.

What exactly is “calibration” and why is it so important in laser/IPL treatments?

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What is ‘calibration’ exactly and why is it so important? Imagine you’re driving along the road and your speedometer is not working properly. You look at it and it claims you’re moving along at 30 mph. But you notice that everyone else is driving past you and you seem to be going too slowly… This… Continue reading What exactly is “calibration” and why is it so important in laser/IPL treatments?

I’ve known for a long time that black and white are not ‘colours’. But I didn’t know that purple is also not a colour…

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In physics we define ‘colour’ by its wavelength. But there are colours which do not have a wavelength – black and white are the obvious ones. Black is when there is no light at all, and white is when all the colours in the spectrum ‘combine’ together into one beam of light. But, I recently… Continue reading I’ve known for a long time that black and white are not ‘colours’. But I didn’t know that purple is also not a colour…

Laser Diode powers – What does it all mean?

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Diode laser suppliers often quote ‘power’ when trying to sell their equipment. They know, of course, that most people don’t have a clue about what they actually mean!! I wrote about this before (link) but here I go again… Power Power is essentially how quickly, or how slowly, energy is delivered. Remember, ENERGY is the… Continue reading Laser Diode powers – What does it all mean?

Hair removal – Diode, Nd:YAG or Alexandrite lasers. Or IPLs? Which is “best”?

Posted in Lasers and IPLs - hair & vascular & pigmented lesions, Theoretical stuff - tissue denaturation / selective photothermolysis....Leave a comment

Hair removal using light is currently the most popular aesthetic treatment on the planet today, apparently. These days we use diode, alexandrite and Nd:YAG lasers and IPL systems. But there appears to be some confusion over these different devices, with all sorts of dubious claims. Let’s go back to first principles… How does this treatment… Continue reading Hair removal – Diode, Nd:YAG or Alexandrite lasers. Or IPLs? Which is “best”?