Surveys have shown one third of Kiwis think science is too specialised to understand. In this series, scientists who tackle mind-bogglingly complex problems each day make it simple for us. Today, we talk lasers with Cather Simpson, a Professor of Physics and Chemical Sciences at the University of Auckland's Photon Factory, and lead inventor at Engender Technologies

How would you describe what you do to a peer at a conference? And then how would you to a stranger at a barbecue?


"I study vibrational energy redistribution in large molecules in the condensed phase using time resolved femtosecond transient absorption and two-pulse resonance Raman. We model the electronic dynamics with multiconfigurational quantum chemistry as well. On the more applied side, we're trying to understand and exploit laser ablation in a wide range of materials, but mostly in dielectrics these days."


Barbecue: "I'm a scientist that uses laser to study how substances convert light energy into more useful forms. It's happening in your body right now. The first step in vision uses a molecule to absorb light and turn it into a rotational motion. The first step in photosynthesis converts light into a little battery. And right now, the sunlight is hitting the molecules in your blood. They convert light into molecular scale heat, so you don't degrade in the sun. We also use that light carried by energy to cut things very precisely, and to do things like sort sperm by sex for the dairy industry."

What project or projects are you currently working on at the moment and what's involved?

The Photon Factory is a big lab – we'll have about 50 people in the group this summer.

That means we have lots of projects on.

The big one we're gearing up to tackle right now is how combine additive - involving 3D printing - and subtractive - involving laser micro-cutting - laser micromachining to make things you can't make any other way.

Super-resolution - featuring tinier than the wavelength of light we are using - is an obvious one, but we're also looking to make shapes that you cannot create with just 3D printing or just laser micro-cutting.

Engender's also at a really exciting place.

That's our sperm sorting spin-out company.


We recently reached an important milestone, and we're now gearing up for the full on commercialisation process, something I'm keen to see to success.

That's a very different kind of problem, though.

What are the trickiest questions facing your field and why is solving them so difficult?

This one is hard to answer, because our R&D spans everything from the very fundamental studies of what's happening to molecules in the first picoseconds - equal to one trillionth of a second - or so after absorbing light, to the fully commercial applications like Engender, Orbis Diagnostics and now our new Smart Ideas project to create a hand-held device for diagnosing and typing skin lesions.

I guess I'll choose one in the middle of that spectrum – the laser micromachining with ultrashort pulses.

This technique has huge potential for industry, but it's really inefficient.


The very short pulses - around 100 femtoseconds, or one quadrillionth of a second - create beautiful features, but they don't carry very much energy per pulse, because they are so short, and so the processing speeds are too slow.

Professor Cather Simpson demonstrates photonics to pupils from Northcote Primary School. Photo / File
Professor Cather Simpson demonstrates photonics to pupils from Northcote Primary School. Photo / File

You can't just turn the laser power up, because the pulses don't behave properly when you do that – they are so intense that they interact in strange ways with matter, creating plasmas, different colours of light, and other effects.

So we have to be more clever than that – which is fun, but harder than just cranking up the laser power.

What do you feel are the most interesting or fascinating aspects of your field?

At the moment I'm actually pre-occupied thinking about the Photon Factory as an innovation hub – a kind of idea pipeline from the university to the world.

We've spun out two companies and two more are in the works.


I don't want to be a company CEO myself; my values are in the university.

So how can I make this sustainable?

Ten years from now, I'd like to look back and see a dozen or more small companies sprinkled about the NZ economic landscape – students and staff creating jobs for themselves and their colleagues, and helping drive a thriving New Zealand economy at the same time.

To do that, I'm thinking about the right balance of effort in the fundamental, applied and fully commercial space – you have to tap into all of these to really succeed.

The people are the most important bits – how do we maintain and rejuvenate our optimistic, innovative spirit?

Especially when the group turns over relatively frequently as people graduate and get "real" jobs?


How will we handle our first big failure?

How do we dampen out the highs and lows of the very tight NZ funding system, so we don't lose momentum in the lean times?

How can we tap into the long-standing intellectual exploration values of a university, but applied to practical entrepreneurship, so that our people can spread their innovative wings with deep understanding, wrap-around mentoring and access to expertise?

Why do you think the work is important and what could it help us understand?

The interaction of light with matter is one of the most important fields of study at the moment, because we are in the middle of a transformation from understanding it to exploiting it.

These are going hand-in-hand, informing each other in a really interesting way and each new discovery of some fundamental behaviour leads to new technology pretty quickly.


That's why the 21st century is the age of photonics – in the same way that the 20th century was the age of electronics.

Photonics is the creation, manipulation and application of light to do useful things.

It's all of the advances in photonics that underpin our ability to realise everything from better, faster, cheaper cell phones and computers to cost-effective, sustainable, environmentally-friendly indoor farming - much less to even imagine a hand-held "tri-corder" that can tell you whether you've got skin cancer or not.

It's a really exciting time to be a laser scientist.