Spectrally Stabilized Semiconductor Lasers Enable Next Generation DPSS Lasers

Vancouver, WA USA  January 17, 2008

Narrowed spectrum and temperature insensitivity make DPSS lasers more robust and efficient

The quest for higher laser system efficiency and insensitivity to operating environments is driving an industry trend toward upper-state laser pumping. While most commonly pumped at the 808 nm absorption line, Nd:YAG and Nd:YVO4 can also be pumped around 88x nm, resulting in a lower quantum defect (lower waste heat) and reduced thermal-lensing of the laser gain media. The absorption lines near 88x nm are much narrower than at 808 nm, thus requiring a semiconductor laser pump with a spectral width substantially narrower than the 3 nm industry standard. 

nLIGHT has demonstrated the ability to spectrally lock semiconductor laser bars and single emitters, which enable applications like upper-state DPSS laser pumping and rubidium pumping. Up to 7-bar stacks have been spectrally locked and are being utilized by DPSS laser manufacturers developing their next generation products. Additionally, nLIGHT has wavelength stabilized its Pearl™ Fiber-Coupled Module to provide spectrally narrow high-brightness fiber-coupled pump sources. Free-running, the spectral width is typically 2.5 nm FWHM, while locked the spectral width decreases to <1.0 nm FWHM.

Just as significant as the decrease in spectral width is the ability to reduce temperature sensitivity of the semiconductor laser, and thus the complexity and cost of system temperature control. With spectral stabilization, the semiconductor lasers remain spectrally locked over a 10 ºC operating temperature range. “Locked laser performance over a wide temperature range is of paramount importance to equipment manufacturers,” commented Chris Ebert, nLIGHT Product Line Manager. “System manufacturers find the opportunity to reduce their system level environmental tolerances highly desirable, which directly leads to more robust and cost-effective system designs.”

nLIGHT will be discussing its spectrally locked results at the Photonics West Conference in San Jose, CA, January 22-24, 2008.