Triple Additive/Subtractive Raman Spectrometer

Raman spectroscopy is an extremely common technique in many areas of science and industry but the new triple additive/ subtractive Raman Spectrometer is no common machine. It is the ultimate tool for pushing the limits of the technique. “As far as equipment is concerned we have nothing to envy of anybody,” says Victoria University physicist Pablo Etchegoin. “I think most people actually envy us!”

About the Instrument:

The new machine has fourteen laser lines to choose from, ranging from the near infrared to the UV. The old one only had four. One of the main advantages of the new set up is that it allows you to change lasers without disturbing the alignment of the system. The new machine has extremely high resolution for picking out fine details in the spectrum. It has two types of detector: a CCD screen, for capturing an entire spectrum and a photo-multiplier detector, which measures the way a single energy evolves over time with nano second resolution. Low temperature facilities allow for measurements down to 77 K (-196°C) in the microscope and 8 K (-265°C) in the separate closed cycle cryostat.

Transforming Research:

Pablo’s chief area of expertise is Surface Enhanced Raman Spectroscopy (SERS). His group is using this technique to detect and analyse single molecules in incredibly low concentrations. This could be used for early detection of diseases among a host of other applications. However, fundamental questions remain about the geometry and statistics of single molecule detection and these gaps in understandingare holding back some of the practical applications. The new spectrometer finally gives Pablo’s group the tools to resolve these questions. Matthias Meyer, a recently graduated PhD student of Pablo’s says that one of the group’s greatest strengths is its ability to push the equipment to its absolute limits. “I spoke to a guy from Taiwan,” he says, “who had the same machine as we just bought. He said it’s really hard to use. They don’t do much with it. They just didn’t know how to do cool science with it, whereas here, we know exactly why we bought it.”

Transforming Relationships:

Pablo is a great believer in the policy of sharing and collaboration. The thing about Raman spectroscopy is that you can use it on just about anything and get some data out. It’s an incredibly multidisciplinary area involving chemistry, physics, engineering and biology and Pablo has a particular knack for bringing the disciplines together. “From rubbish bins to single molecules,” Pablo says, “we do everything that comes in.” The group was once approached by a rubbish dump manager wanting to test a sample for contaminants. “I’ll do it as long as it’s not too smelly,” Pablo replied and a sample of rubbish arrived in the lab. The ability to change lasers has opened up vast new areas of research and attracted many new users. It has spurred new collaborations with chemists in Japan and at Victoria University probing the orientation and properties of individual carbon nanotubes. It has also rekindled Pablo’s collaboration with his ex-colleagues at Imperial College in the UK. There is even a team of researchers from SCION, the Crown Research Institute for forestry research in Rotorua, using the new spectrometer on a regular basis. They were overjoyed to find a local instrument with the added bonus of having experts at hand happy to help them use the equipment and interpret results. Pablo and the team are happy to train outside researchers to use the equipment or, for short term projects, to do the work themselves on a consultancy