As a confirmed space-geek ever since Halley’s Comet in 1986, lasers, or perhaps I should say laser guns in their various forms, have always been a part of my life. I’m not sure if I first met lasers in Star Wars or being fired at Doctor Who by a Dalek. But I do know they made a big impression on me. The lasers of sci-fi are flashy affairs, complete with awesome graphics, sound effects and implausible physics. Perhaps the most iconic being the lightsaber of Luke Skywalker. So I was excited to see the first ever video of a laser beam moving through the air and bouncing off a series of mirrors which was released last month by researchers at Heriot-Watt University in Edinburgh.
In my work, I use a laser every day; not as the Jedi knight of my childhood imaginings, but to measure particle size distributions in a laboratory. The area of technology I work with at Malvern Instruments is laser diffraction. This technique suspends particles in a measurement zone and shines a laser through the particles. As the light encounters the particles, some of it is scattered, and we collect the scattered light. The size distribution of the particles can then be calculated from that scattered light. The optical path of the Mastersizer 3000 laser diffraction instrument involves bouncing the laser off two mirrors using precisely engineered optics, so the Heriot-Watt video really is a glimpse “under the covers.”
Our other laser diffraction systems are Insitec, for in-line analysis, and Spraytec which measures droplet sizes in sprays. The Spraytec only has one mirror in its optical path, but as the measurement zone is open to the spray, you can see the laser in action during the measurement.
Other Malvern products use lasers as a light source including the Zetasizer range, which can measure particle size, electrophoretic mobility of proteins, zeta potential of surfaces and microrheology, and NanoSight, which uses nanoparticle tracking analysis to measure particle size.
Lasers are not only used as light sources for scattering techniques: the Archimedes detects the displacement of a minute cantilever using a laser, and from this can measure the mass of protein molecules. The Morphologi G3-ID combines advanced visible light microscopy with laser-powered Raman spectroscopy for chemical identification.
As 2015 is the International Year of Light (IYL) – that’s all light-forms, not just lasers – we can expect to hear more about the application of light-based technologies in the coming months. At the UK launch of the IYL, the Duke of York said: “The International Year of Light is about how we have used light over the centuries; it is about how we are applying light, photonics and various other aspects in order to make the world a better place, not only for ourselves, but for future generations.”
Here at Malvern Instruments, we are proud to be a part of that mission, and to take part in some of the IYL-inspired or themed events, such as Pittcon 2015. You can read about the short courses we are running at Pittcon in our recent blog post. The short courses are discounted until February 20 so get booked up as soon as you can!
Check out these interesting applications of laser diffraction: