Reflect action

BAE Systems is investigating bimorph deformable mirrors in a bid to create a device that will help fighter pilots see more clearly.

Eagle-eyed fighter pilots should be able to see even more clearly with a device adapted from astronomical telescopes.

Defence and aerospace giant BAE Systems is investigating a type of flexible mirror, called a bimorph deformable mirror, to sharpen up camera imagery and improve laser range and power. The company hopes to develop manufacturing processes to reduce costs from millions of pounds to just thousands.

Senior principal scientist at BAE Systems’ sensor technology department Dr Leslie Laycock said the bimorph mirrors, which can change their shape to improve the way they modulate light, could have many applications.

‘Some electro-optical systems have an upper limit of performance. This technology can either raise it or make the same performance cheaper.’

The mirror would be used with electro-optical devices carried by military aircraft that emit, modulate or sense light for various purposes including target detection and surveillance. These include daylight, ultraviolet or infrared cameras.

Any optical system that relies on propagation of light through the atmosphere can suffer disturbance due to particles or high air temperatures. The resultant haze blurs any images recorded.

The device works by using piezoelectric material glued to a gold-layered glass substrate. The electrodes are arranged in a web-like pattern, and when a current is applied they can stretch and bend areas of the glass by tiny amounts. Working at about 1,000 operations-per-second, this flexing and warping effect can be used to cancel out blurring of images or concentrate laser beams.

When used in conjunction with a camera the mirror would include a sensor to measure the aberrations in the air that cause distortion, and a control system to drive the mirror. ‘You have to sense the distortion, do the processing, then send a signal to all the electrodes,’ said Laycock.

A laboratory test bed began operating at the Great Baddow site earlier this year, and different units in BAE Systems are taking turns to try out the technology. Outdoor tests are scheduled for the end of this year.

Laycock added that the next generation of military laser pods could use deformable mirrors to concentrate laser beams to get longer range or higher power. ‘There are applications where you might want to use it with a high-power laser, therefore we are looking at water cooling systems.’

Originally developed for large astronomical telescopes and military spy satellites, bimorph deformable mirrors are being experimented with elsewhere for focusing directed energy weapons such as the Airborne Laser. But Laycock would not comment further on whether BAE Systems was developing similar weapons.

Similar mirrors have even been touted as a device to make perfect glasses. Eyecare company Bausch & Lomb and the University of Rochester in the US are developing the technique to counter distortions in people’s eyes.