Today, Lisa and Mike take another look at the fascinating world of laser physics, particularly in the context of medical aesthetics. They explore various pulse regimes - nanoseconds, picoseconds, and femtoseconds - discussing their implications for energy delivery and tissue reactions. Mike explains the significance of these time scales, including the concept of zeptoseconds, and how they relate to the behaviour of atoms and light.

KEY TAKEAWAYS

Different pulse regimes (nanoseconds, picoseconds, femtoseconds) affect how energy is delivered to tissues. Shorter pulses (like nanoseconds) allow energy to be absorbed quickly, leading to higher temperatures in the target area, while longer pulses (like milliseconds) allow heat to dissipate, resulting in lower peak temperatures.

The type of reaction elicited in tissues depends on the pulse duration. Longer pulses tend to produce thermal reactions, heating surrounding tissues, while shorter pulses can create photomechanical reactions, where rapid heating leads to physical disruption of target materials, such as tattoo ink.

To prevent unwanted thermal damage during laser treatments, proper cooling techniques are essential. Cooling the skin and surrounding tissues can mitigate excessive heat generation, reducing the risk of burns and other adverse effects.

When purchasing aesthetic lasers, it is crucial to look beyond marketing claims and focus on technical specifications, such as output power, wavelengths, fluence range, and pulse widths. High fluences are associated with better treatment outcomes.

Effective training for non-physicist clinicians involves breaking down complex physics concepts into tangible, relatable ideas. Using everyday analogies can help clinicians grasp the fundamental principles of laser physics, making it easier for them to apply this knowledge in practice.

BEST MOMENTS

"The shortest ever unit of time that's been successfully measured by scientists was an event that lasted 247 zeptoseconds. This is the time that it took for a photon to cross a hydrogen molecule."

"I didn't think hydrogen atoms were that big because 0.1 nanometers isn't really so small, is it, when you think about it?"

"If you have a long pulse, like in the millisecond regime, then because the heat is escaping during the pulse, we tend to get a thermal reaction."

"Generating too much heat is very easy to do. It's quite hard to be precise because it depends on where the absorbing targets are and how deep they are."

"If they're not giving you the technical spec, it's a bit dubious."

ABOUT THE HOSTS

Mike began his career in medical lasers in 1986 with a physics degree and a post-grad in bioengineering. He helped develop the scar-free removal of tattoos using a Q-Switched Ruby Laser in Glasgow, and the world's first IPL system. Known well in the industry for his hard truths, no BS attitude and logical answers. As the author of three books, articles for medical journals, a well read blog, a Laser Protection Advisor and contributor to the BMLA, Mike is the Laser Guru.

Lisa's claim to laser fame is being Mike's daughter. Growing up with lasers and never avoiding a physics lesson from her Dad, it was natural to enter the industry. Leaving a corporate career with a baby to jump into self employed life came with challenges. Despite that Lisa has been well recognised for her teaching style, practical tips, bringing the compassion to the science, and laser mentoring.

Instagram: @dermalase_lasertraining

https://mikemurphyblog.com

https://www.dermalasetraining.com

This Podcast has been brought to you by Disruptive Media. https://disruptivemedia.co.uk/

More Science: From Femtoseconds to Zeptoseconds