Bilkent University, Ankara, Turkey
01 November 2018, Thursday, 14:40
Cavid Erginsoy Seminar Room, Physics Department, 3rd floor
Abstract: Since its invention, the laser has been idealized as the perfect cutting tool that can work with ease and surgical precision on any material. But the reality has turned out to be different. High-power lasers can indeed cut through industrial materials such as thick steel, but very slowly, and only by enormously heating the entire target. The solution was hailed to be "ultrafast pulses" that can indeed make exact cuts and virtually avoid all heat damage to surrounding material.
But, how do you amplify a laser pulse to be so powerful that it can cut through any material nearly instantaneously without destroying the powerful laser that is supposed to amplify it? The answer came in 1985 from G. Mourou and D. Strickland. They invented a method based on stretching the pulses before amplification and then compressing them back in free space (air) after amplification. Today the overwhelming majority of ultrafast lasers use their invention. They were awarded half of the 2018 Nobel Prize in Physics.
Thus, this invention made powerful ultrafast lasers possible. But, after 30 years, ultrafast laser surgery practically does not exist outside of very specific eye-surgery operations. Why not? The reason is that they are extremely slow and inefficient, as well as requiring expensive laser technology.
We have recently combined the invention of Mourou and Strickland with a key idea from "rocket science" and invented ablation-cooled laser surgery that circumvents all of these pitfalls (Ilday et al., Nature, 2016). Laser pulses are sent so quickly one after another that the heat from the laser is ejected away with the ablated material, keeping the rest of the target material cool, in addition to increasing efficiency by more than ten times. We also reduced the required laser pulse energies by 1000 times and achieved record speeds in cutting biological tissue, as well as metals and semiconductors.
Can ablation-cooled laser surgery initiate a new era of laser surgery that approaches its idealized image?