New X-ray glasses concentrate, strengthen laser beams

March 1 (UPI) -- Scientists at the Deutsches Elektronen-Synchrotron, or DESY, the German research center, have created laser beams with record strength and precision using X-ray glasses.

The lens can successfully concentrate 75 percent of a laser beam onto a spot just 250 nanometers wide -- precision approaching upon the theoretical limit.

"Only a few materials are available for making suitable X-ray lenses and mirrors," Andreas Schropp, a researcher at DESY, explained in a news release. "Also, since the wavelength of X-rays is very much smaller than that of visible light, manufacturing X-ray lenses of this type calls for a far higher degree of precision than is required in the realm of optical wavelengths -- even the slightest defect in the shape of the lens can have a detrimental effect."

X-ray lenses are commonly made from beryllium, but their production often leaves them too curved in the middle and with slight imperfections.

"Beryllium lenses are compression-moulded using precision dies," Schropp explained. "Shape errors of the order of a few hundred nanometres are practically inevitable in the process."

For most applications, such errors are acceptable and unnoticeable, but for certain imaging technologies, the laser beam must be as precise as possible.

The scientists didn't attempt to rid their beryllium lenses of their inevitable flaws. Instead, the optics researchers precisely measured the flaws in their beryllium X-ray lens stack and used the data to construct a corrective lens made of quartz.

Without the corrective quartz lens, the beam focused onto a spot with a diameter of 1,600 nanometers.

"That is about ten times as large as theoretically achievable," said lead researcher Frank Seiboth. "When the glasses were used, 75 per cent of the X-rays could be focused into an area of about 250 nanometres in diameter, bringing it close to the theoretical optimum."

Scientists tested their new corrective lens on two lasers, DESY's synchrotron X-ray source PETRA III and the British Diamond Light Source, but say their methods can be used to make a corrective lens for all types of X-ray lasers.

The new research was published in the journal Nature Communications.