Wavelength converter wins award for Lawrence Livermore Lab

22 Aug 2006

US National Ignition Facility Project team wins recognition for development of color-changing laser.

Lawrence Livermore National Laboratory, Livermore, CA, US, has been awarded an "R&D 100" award for developing a high average power wavelength conversion device that can change the color of laser light.

Wavelength shifter

The photo shows a yttrium calcium oxyborate (YCOB) crystalline plate in an optical mount, foreground).

[Invisible] Infrared light enters from the right and passes through the YCOB crystal. Some of the infrared light is wavelength shifted (frequency converted) to the visible (green), and the second harmonic or green light emerges from the crystalline plate on the left before hitting an energy detector in the background.

LLNL laser scientists say that the converter will permit large aperture, high average power lasers to operate at half the wavelength of the laser crystal's natural emission wavelength.

The device, which is based on the YCOB crystal, was developed in tandem with Crystal Photonics, a company based in Sanford, FL, US.

"Many of today's lasers operate in the infrared portion of the spectrum - a color or wavelength that is not the most efficient for some applications," commented an LLNL spokesman. "Both the YCOB crystal's ability to handle heat and its ease of growing could permit some of these lasers to operate more efficiently at the shorter wavelength."

As examples, ceramics and plastics could be more efficiently machined with ultraviolet light, and copper metal for electronic circuit boards could be more efficiently cut with green light.

The LLNL YCOB wavelength converter holds the current world record for an average-power, high-pulse-energy laser at 225 W of 523.5 nm light, at a repetition rate of 10 Hz and 22.5 J per pulse. One YCOB crystal can replace eight optical components.

The conversion device and YCOB crystal were developed by LLNL employees in the National Ignition Facility and Engineering directorates.

The development of the YCOB crystal is a direct consequence of LDRD funding since 1997. This money was awarded to study the use of a solid state laser as a potential replacement for the copper vapor lasers in the Atomic Vapor Laser Isotope Separation program. The funding allowed researchers to study new nonlinear optical crystals.