Laser System suits absorption spectroscopy applications.
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Press Release Summary:
Single-frequency, continuous-wave (CW) MgO:PPLN optical parametric oscillator (OPO) provides continuous tuning in mid-IR wavelength range. Pumped by fiber laser coupled with fiber amplifier, unit generates over 1 W of continuously tunable output in 2-4 micron range and exhibits stable, CW operation at room temperature. Applications include methane gas detection and water vapor sensing.
Original Press Release:
Aculight Corporation Develops Broadly Tunable Mid-IR Laser System for Absorption Spectroscopy Applications
Bothell, Wash., April 18, 2005 - Aculight Corporation, a leading manufacturer of innovative laser technologies for industrial and government applications, has developed a novel fiber-pumped singly resonant optical parametric oscillator (OPO) that provides continuous tuning in the mid-infrared (IR) wavelength range. This prototype laser system has been 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. Currently however, scientists rely on either external cavity diode lasers or lead-salt diode lasers to perform spectroscopic measurements-both technologies exhibit significant performance 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. "And 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 Corporation has developed a fiber-pumped OPO that generates over a watt of continuously tunable output in the two- to four-micron range. For many spectroscopists, this will provide an enabling tool to conduct a wide variety of high-precision experiments.
Aculight's device is a single-frequency, continuous-wave (CW) MgO:PPLN OPO pumped by a fiber laser coupled with a fiber amplifier. Singly resonant OPOs have long shown potential for spectroscopy applications that require widely and continuously tunable mid-IR output. However, previous devices have been limited by the high power required to exceed oscillation threshold, and by the need to heat the nonlinear material to avoid photorefractive damage. In contrast, Aculight's new device exhibits stable, CW operation at room temperature with an oscillation threshold that has been reduced by 70 percent over previous systems. "This is the least amount of power to date that's been required to switch one of these devices on," said Henderson. "It ultimately makes for a more user friendly, much less costly, less bulky laser."
The device also benefits from recent advances in fiber laser technology. "Today's fiber lasers provide high power, excellent beam quality, narrow linewidth and continuous tuning. This is the full package of capabilities necessary for pumping a singly resonant OPO and, as a result, the OPO can operate with narrow linewidth and wide mode-hop-free tunability-key requirements for spectroscopy," said Henderson.
Aculight originally developed fiber-pumped OPO technology for both 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.
This new technology further reinforces Aculight's position as a leading developer and supplier of fiber lasers and laser systems to commercial and government markets, along with its specialty in tailoring laser output to wavelengths of interest for customers. Aculight's frequency-converted fiber laser systems enable the use of fiber technology in markets that demand output in the green, UV and IR wavelengths. These include scientific, materials processing, medicine and defense, among others. Fiber laser-based systems are especially desirable for many applications because their all-fiber designs are more reliable, efficient, compact and rugged than other laser technologies.
Founded in 1993, Aculight Corporation develops and manufactures innovative laser technologies for the industrial, research, government and medical markets. Aculight's technology portfolio includes fiber lasers, diode-pumped solid-state lasers, nonlinear optics, and external cavity diode lasers. For more information about Aculight, please contact Andrew Brown, director of business development, at (425) 482-1100, or visit www.aculight.com.
