Over the last few decades, physicists have been building lasers capable of delivering shorter and shorter pulses, down to a millionth of a billionth of a second. Why would one care to look at those short timescales? For example, because this allows us to image the motion of molecules as chemical reactions unfold. It's also practically useful, for example in laser eye surgery, because very short laser pulses do not have time to heat up the tissues, limiting unwanted damage. How do you make a very powerful short pulse? You need to amplify it. This quickly becomes problematic, however, if you want really high power, since the laser pulse itself may damage the amplifier. To solve this problem, Donna Strickland, together with her colleague Gerard Mourou, came up with a brilliant idea known as "chirped pulse amplification". The idea is to "stretch" the laser pulse, making it longer to decrease its peak power and not to destroy the amplifier. After amplification, the laser pulse would then be re-compressed to very short time-scales. This invention led to the 2018 Nobel Prize in Physics.
Want to learn more?
The study of lasers forms a core part of all physics degree programmes at Heriot-Watt (2ndyear course B28PO Photonics and Optics and 4th year course B20ES Electromagnetism and Laser Physics). Additionally, during summer internships and final year projects there are many opportunities to get to grips with cutting edge research on building ultrashort laser systems and using them for a wide range of applications including sensing, molecular imaging, welding, and writing wave-guiding structures for optical communication.