IF YOU'RE planning watch a DVD today, listen to a CD, play a computer game, go to a supermarket, browse the web, or do 100 other everyday tasks, spare a thought for the invention that has shaped our lives and revolutionised our manufacturing industries: the laser.

The name is an acronym for Light Amplification from the Stimulated Emission of Radiation. It works by pumping electrical energy into a "gain medium" (a gas, solid, liquid or plasma). This stimulates the emission of light, which is then amplified by being passed backwards and forwards in a cavity. In its simplest form, this consists of mirrors at either end. Light bounces back and forth off them, each time passing through the gain medium, and is amplified with each pass. Typically one mirror, called the output coupler, is partially transparent, which is how the output laser beam is emitted.

A laser beam is special because it's what physicists call "coherent"; it consists of waves that all have the same frequency and are in step with one another. This makes it different from, say, a flashlight beam, the light waves from which will have different frequencies and typically be out of phase with one another.

The reason we're celebrating the laser this year is that 50 years ago Theodore Maiman, a researcher at the Hughes Research Labs, built the first one, using a ruby crystal to produce a beam of red light. Later the same year, a group of physicists built the first gas laser, using a mixture of helium and neon.

Since then the technology has been developed, miniaturised, commoditised, extended and deployed to the point where it's virtually impossible to find a manufactured product that hasn't encountered a laser at some stage in its creation or use. When you play a DVD, a semiconductor laser less than a millimetre wide scans the disc's surface. The intricate cutting and welding of the steel in your car door was done by lasers. The internet's backbone runs mainly via laser light transmitted along fibre-optic cables. Every supermarket checkout uses a laser beam to scan barcodes. American forces in Afghanistan are now using powerful lasers mounted on Humvees to detonate any roadside bombs ahead of them.

Lasers are thus a critical part of our technological infrastructure, yet no one involved in the research that led to them had any inkling of what their investigations would produce. The original idea goes back to a paper Albert Einstein published in 1917 on "The Quantum Theory of Radiation" about the absorption, spontaneous emission and stimulated emission of electromagnetic radiation. For 40 years, stimulated emission was of absorbing interest to quantum physicists, but of little interest to anyone else – certainly to nobody in government.

Which brings us to Lord Mandelson, now in charge of all government funding of universities and academic research. He has no personal experience of research in science or technology, but, like many people whose minds are unclouded by knowledge, has strong views on these matters.

In his first speech after taking control of Britain's research spending, for example, he "made no apology for prioritising research that would contribute to Britain's future prosperity". The occasion was the celebration of the centenary of the Science Museum, and Mandy left his listeners in no doubt that he will continue government policy of allocating more of the £6bn science budget to areas with commercial applications – in other words, areas that the government (and its industrial advisers) think will yield short-term benefits for Britain.

Meanwhile, at the Higher Education Funding Council for England, the geniuses who presided over the disaster of the Research Assessment Exercise – which sets funding to universities based on the perceived "value" of their research – have been adjusting to the Mandel­son line. They are working on a "Research Excellence Framework" which will require applicants for funding to cite "demonstrable benefits to the economy, society, public policy, culture and quality of life". This bodes ill for any scientist or engineer interested in curiosity-driven research.

The laser has become vital for our way of life, yet no researcher who worked on it after Einstein's paper could have predicted what would emerge. If Mandelson had had anything to do with it, we'd be reading barcodes by flashlight.