Galway's state-of-the-art laser waiting to provide solutions

The National Centre for Laser Applications at NUI Galway has installed a remarkable new laser device. It emits a powerful energy pulse that lasts for just 30,000-billionths of a second and is one of only four such devices installed anywhere in Europe.

"This new laser will allow us to provide this cutting-edge technology to Irish companies for the first time," stated Dr Gerard O'Connor, manager of the NCLA at Galway. "The first industrial research project based on this new technology has just been agreed between the NCLA and a leading global manufacturer of micro-components."

The NCLA has a long history of collaboration with Irish firms, explained Mr Tony Flaherty, senior research scientist at the centre. "It was established in 1989, basically in response to demand from industry."

Large technology companies based in the west such as Digital and CR Bird, now Medtronic, were looking for research support in laser technology. The university got grant aid from the then Eolas to develop and provide a research service to industry, Mr Flaherty said.

Laser applications are of particular value to production and process engineers but too few of them have expertise in this area, he explained. "The market is really looking for expertise in this technology," he added. "Traditionally the laser has been a solution looking for a problem."

The NCLA began with contract work but has expanded to include the patenting of processes with industrial partners. "The interaction with these companies has had a knock-on effect for research at the college," he said. "It kind of creates a one stop shop."

The centre has 17 researchers including postgraduates. "It is focused largely on the transfer to industry of laser technology." Companies with specialised manufacturing, machining or drilling requirements where a laser might be an option come to the centre as a way around a problem.

The new device, known as a femto-second laser, will greatly expand research frontiers for the NCLA. It was purchased with funding from a Higher Education Authority grant, which established the National Biomedical Engineering Science Centre at NUI Galway.

The new laser is a state-of-the-art device, so much so that applications for it are only beginning to arise. "The first paper describing the femto-second laser only came out about two years ago. Most of the things being done with them are very, very new."

A femto-second divides a second into a million billion parts. The new laser fires pulses of focused light energy that last a few hundred femto-seconds, discharging a stream of 1,000 pulses per second.

The single beam is actually created by three separate lasers, Mr Flaherty said. "The laser itself is three lasers in one." The first semiconductor laser creates the pulse, the second YAG pump laser stretches and amplifies the pulse and the third titanium sapphire laser recompresses the pulse before it strikes the surface.

The great advantage of this device is that it does not produce a lot of heat, causing melting in the sample. The pulses are extremely powerful but are so short that heat does not conduct down, even with metals such as aluminium or copper, Mr Flaherty explained.

"Heat doesn't go into the sample so it is confined on the surface. This is the key to the laser as a machine tool. You can machine away at the surface without affecting the surrounding area."

Dr O'Connor described the advantages to manufacturers of the device. "The key benefits of such ultra-short pulses lie in their ability to deposit energy into materials in a very short time interval, offering significant advantages over conventional laser sources in high-precision applications such as micro-machining, micro-drilling and ultra-precise cutting."

For this reason the medical device industry is keen on laser technology, Mr Flaherty said. Galway has developed as a European centre for the manufacture of medical devices and thousands are employed in companies such as Boston Scientific and Medtronic AVE.

"It is a very innovative industry," Mr Flaherty said. "This new tool offers a whole new range of potential uses." Very fine holes can be drilled in devices for the controlled delivery of drugs or for the capture of individual cells.

The electronics area is also a target market for the device, he said. MEMS, micro-electro-mechanical systems, are becoming important to this sector for the creation of tiny pumps and smart sensors that can be built into microelectronic substrates. Other areas include uses in the aeronautics industry and in optical electronics and communications.

Precision drilling using lasers was previously limited by the wavelength of the laser light being used, in practice about 0.7 microns (a micron being a millionth of a metre). This new device takes this down to 0.5 microns, Mr Flaherty said.

The femto-second laser can also work materials that previously resisted laser cutting such as industrial diamonds and other transparent materials. It delivers so much energy that only a tiny fraction must be retained at the surface to cut and machine so even glass and highly reflective surfaces can be processed.