Safety specs stop femtosecond pulses

17 Jun 2003

Eyewear that gives peace of mind to scientists using modelocked lasers goes on sale.

The first off-the-shelf laser safety eyewear that guarantees protection from ultrashort pulses is now on the market. The news is likely to please users of picosecond and femtosecond lasers that have been patiently waiting for spectacles with the appropriate safety rating.

LaserVision of Germany claims that it is the first manufacturer of safety spectacles worldwide to demonstrate that its eyewear meets the modelocked specification (designated part-M) of European laser eyewear standard EN-207.

“There’s now definitely a demand for it,” commented Paul Tozer from Lasermet, a leading laser safety specialist in the UK. “We used to have people from one UK lab calling us up every six months to find out if we had any.”

EN-207 is split into four protection categories: D for continuous-wave lasers; I for pulsed lasers (100 ns to 0.1 s pulse duration); R for Q-switched lasers (1 to 100 ns); and M for modelocked lasers (less than 1 ns).

According to BFi OPTiLAS, a European distributor for LaserVision products, M-rated eyewear that covers the typical wavelengths of Ti:Sapphire lasers is now available and protection for other wavelengths will soon follow.

In the past, commercial eyewear has only been tested for D, I and R ratings as the market for M-rated eyewear was considered relatively small and the testing considered time-consuming and expensive. As a result, users of ultrashort lasers had to use either R-rated eyewear or arrange for custom built protection.

However market conditions have now changed. Today, affordable diode-pumped femtosecond lasers are found in applications ranging from laser chemistry and multiphoton imaging to materials processing.

“Lots of people in universities and research labs are now building or using short-pulse lasers and need appropriate protection,” said Fiona Evans from BFi OPTiLAS UK. “Tests have been running for a year to achieve this M-rating. In the past, the only option was to test eyewear yourself.”

Author
Oliver Graydon is editor of Optics.org and Opto & Laser Europe magazine.