Arthur Ashkin was at Bell labs in 1970 when he discovered the force within a laser beam that could trap small beads of glass. A typical laser beam is strongest in the center, such that radiant pressure on small objects can draw them towards the center of the beam. This ability to manipulate microscopic objects by laser light has become known as the optical tweezer. Since then the scientific community has designed systems to repel objects from the beam center and devised laser beams with hollow centers to trap particles without the side effect of heating the particle being trapped. Ashkin’s invention has driven a wealth of fundamental optical physics research worldwide. This invention has also gained traction in biophysics for its ability to manipulate biological matter. One such example was determining the tensile strength of deoxyribonucleic acid (DNA), by simply attaching an of the DNA strand to a minute glass bead and pulling with an optical tweezer to measure the physical forces within. Optical tweezers can move and control biomolecules in the presence of others, so that biological processes can be monitored and regulated.
At the Institute of Optical at the University of Rochester, Gérard Mourou and Donna Strickland developed a method called chirped pulse amplification in the mid- 1980s. This method stretches a femtosecond (10-15 s) laser pulse in time, uses a second laser to amplify it without fear of damage to the equipment, before the compressed the pulse back to its original duration. On the back of twenty years of pulsed laser light development, chirped pulse amplification made a leap in laser power, taking the technology from a research tool to one that is now used in manufacturing. Today laser machining, welding and printing can all claim their origin from Mourou and Strickland’s discovery. In addition, the extreme power offered by modern day lasers employing chirped pulse amplification allow table-top scientist to create short laser pulses across the electromagnetic spectrum, from radio frequencies to x-rays, giving rise to the inner workings of atoms and molecules on the time frame that they naturally operate. Chirped pulse amplification technology also underpins development of international science facilities like the National Ignition Facility at Lawrence Livermore National Laboratory, which is exploring laser-based fusion, and the ELI Consortium in the European Union that aims to provide a versatile platform for interdisciplinary research.
The Royal Swedish Academy of Science honors optical tweezers and ultra-intense laser light, both of which are game changers for scientific discovery and commercial applications.