Applications

"It is lighted neither by window nor by lamp, yet is filled with a soft radiance." This is part of the opening paragraph to E. M. Forster's short story The Machine Stops, in which he describes a small room where the walls themselves glow and light the room. Now, 100 years after its publication, this concept is becoming a reality.

We've previously reported on the use of light patterning techniques to manipulate the movement of particles in solution (Microscopic particle manipulation for screening operations), but now the method has been improved upon and we can see it in action.

The demand for consumer electronics to get smaller, lighter and cheaper, is a stimulus for great ingenuity. Cell phones are a classic example where electrical engineers and designers are constantly working to put a whole lot more into ever smaller spaces. And now that cameras are almost as standard a feature in these devices as the ring tone, optical engineers must also devise increasingly clever ways to shrink the optics while improving their performance.

Counterfeit and smuggled goods are said to be one of the fuels that drive organised crime, so it is essential that products can be identified to determine if they are genuine and where they came from. Some manufacturers go to extreme lengths to incorporate hard to replicate anti-counterfeit labels or devices into their products, but it's a game of catch up and it isn't long before the criminals find a way of defeating those measures. So how about using no anti-counterfeit measures at all? This is the approach being promoted by Russell Cowburn at Imperial College in London, who is researching a method called Laser Surface Authentication (LSA), which relies on unique, microscopic identifiers already inherent in products or their packaging.

Researchers in Germany and the UK have devised a new method for the optical manipulation of microscopic particles and demonstrated it by rotating biological cells under a microscope^†.
 
 

Wasted food amounts to loss of earnings if you're a retailer selling produce. Damaged or rotting fruits and vegetables are routinely thrown out when they can no longer be sold. It is therefore imperative that the retailer buys produce with a good shelf life. But knowing which ones will stay fresh the longest is not always apparent from a visual inspection. Bruised fruit may show no signs of damage on the surface but will be the first to rot.

In an effort to add a little variety and step away from all the new biomedical applications out there that exploit the endless wonder of light, here's a paper describing the use of light to make measurements of ink thickness! Okay, that might seem a little mundane, but it’s a classic example of the way in which light is used to solve an everyday problem, in this case to measure the thickness of black ink, typically a few microns or so, whilst it is spinning on the roller of a printing press at 300 rpm¹.

It's hard to keep up with the ever-increasing number of ways in which light can be used to push on the frontiers of medical science. Here are just a few that have been reported on in recent days.

The ingenious chaps over at Apple Inc. have come up with a bright idea that may one day save you the inconvenience of lugging around chargers and spare batteries for your portable media players and mobile phones.

A biometric identification technique you may be seeing more of in the coming years is vein scanning. The veins inside a person's hand, or just one of their fingertips, are imaged and the results passed through a software algorithm to obtain a unique identifier for that person. In an identification scenario, that person would then be authorised or denied access, depending on whether their identifier matched one in the database and for which access was granted.