Lasers come to the aid of cancer patients

Telecoms, healthcare and display technology will be the major beneficiaries of a new generation of semiconductor lasers developed in a massive European research effort. Better cancer treatment, wider bandwidth and smaller, better displays could be on their way.

The Brighter project, which is co-funded by the European Union, has set a series of world firsts in lab-based records for semiconductor lasers in the red, infrared and green spectra.

These results will not languish on the testing bench. The Brighter project began its work with three, hugely important applications already in its sights.

One of the most compelling is a new type of cancer treatment and imaging enabled by semiconductor lasers developed by Brighter. Photodynamic therapy is a very promising treatment for cancer patients that can maximise the benefits, while minimising the harm, from chemotherapy.

Photodynamic therapy works by introducing an inactive chemotherapy drug into the patient. This drug then seeks out and attaches itself to cancer cells. The drug is then activated by laser.

It is a very promising and potentially highly effective treatment that only releases drugs at cancer cell sites, reducing the side effects and enhancing the impact on tumours.

Scientists developed a range of lasers for different elements of the treatment. Powerful and highly reliable red lasers - one at 635 nm, another at 650 nm - were developed to activate different drugs.

Meanwhile, a high-powered blue laser provides fluorescent spectroscopy to show that the drug has reached the target site. Finally, a high-powered ultraviolet laser provides auto-fluorescent imaging of the cancer site.

Both clinical and experimental animal studies are currently underway for different elements of the treatment and any promising results are likely to be commercialised.

Telecommunications, too, is a compelling application and Brighter has developed a range of elements to respond to pressing needs.

A range of lasers and their associated technology to considerably boost bandwidth across optical fibres for data-intensive telecoms has been developed. The result is more bandwidth in the same pipe, an application that will go a long way to meeting the challenge of rising demand for bandwidth.

In addition to developing a semiconductor of the required quality and power, the project had to develop methods for coupling lasers together, to create an even more powerful light source and then coupling the light to optical fibres.

In displays, Brighter hopes to usher in new products or better, smaller and more efficient versions of existing products. Current applications in sight are extremely small, powerful and efficient light projectors for film, presentations and other applications, such as head-up displays and mobile projectors.

The technology could even be adapted for use with mobile phones, allowing them to project extremely high-quality video for television applications, for example. In the coming months, the high-performance red and green laser modules will be tested for feasibility for display applications.

For all these applications, Brighter has developed and perfected a vast range of fabrication and design techniques for semiconductor lasers, including doping, deposition and external cavities on the semiconductor material to 'tune' the laser, stabilise it or couple it with other lasers, depending on the required results.

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