Aculight Develops Fiber-Pumped OPO

BOTHELL, Wash., April 19 -- Aculight Corp., a manufacturer of laser technologies for industrial and government applications, said it has developed a novel fiber-pumped singly resonant optical parametric oscillator (OPO) that provides continuous tuning in the mid-infrared (IR) wavelength range. The prototype laser system is designed for use in absorption spectroscopy applications such as methane gas detection and water vapor sensing.

Absorption spectroscopy is a highly selective and versatile technique for detecting trace atmospheric constituents in the parts-per-billion by volume (ppbv) concentration range. The mid-IR spectral range is attractive for detecting these constituents, since many trace gases exhibit strong absorptions in this region. Scientists now rely on either external cavity diode lasers or lead-salt diode lasers to perform spectroscopic measurements; Aculight said both technologies have limitations.

"External cavity diode lasers typically emit below two microns where light absorption for many gases is weak," said Angus Henderson, senior scientist for Aculight. "Lead-salt diode lasers emit in the mid-IR region, but must be cryogenically cooled and produce less than a milliwatt output." To address these shortcomings, Aculight said its fiber-pumped OPO generates over a watt of continuously tunable output in the two- to four-micron range, providing spectroscopists with a tool to conduct a wide variety of high-precision experiments.

The device is a single-frequency, continuous-wave MgO:PPLN OPO pumped by a fiber laser coupled with a fiber amplifier. Aculight said it exhibits stable, CW operation at room temperature with an oscillation threshold that has been reduced by 70 percent over previous systems.

Aculight originally developed fiber-pumped OPO technology for the National Institute of Standards and Technology (NIST) and the Air Force Research Laboratory (AFRL). NIST intends to use the system to detect the presence of water vapor in semiconductor manufacturing, where it can spoil wafer yield. AFRL will conduct fundamental studies of hydrogen fluoride, which it intends to use in high-power gas lasers.

For more information, visit: www.aculight.com