22 Sep 2005
The pick of this week's patent applications including a LIBS system for monitoring exhaust fumes from turbine engines.
• Title: LIBS system and method for engine exhaust monitoring
Applicant: Systems Planning and Analysis Inc, US
International application number: WO 2005/081981
Inventors in the US are trying to patent a laser-induced breakdown spectroscopy (LIBS) system which details the make-up of the exhaust emitted by car and turbine engines. "As engine components wear, the material composition of the engine is eroded and exits in the exhaust," explain the authors. "Knowing the composition determines if the engine requires maintenance."
The LIBS instrument uses a high-power laser to generate a plasma in the exhaust. Light emitted from the plasma is then collected and processed in real-time by a computer-controlled spectrometer. Citing a specific example, the authors say a LIBS system for testing a gas turbine exhaust can detect nickel to below 200 parts-per-billion, aluminium to below 20 parts-per-billion and other trace metals to between 10 and 200 parts-per-billion.
• Title: Ultraviolet, narrow linewidth laser system
Applicant: Spectra-Physics Inc, US
International application number: WO 2005/000484
Spectra-Physics, a division of Newport, has applied to patent a narrow linewidth ultraviolet laser. The system comprises at least one diode-pumped alkali metal vapor gain cell to generate near-infrared laser light and at least two nonlinear crystals.
"In one embodiment, the laser uses a rubidium gas cell and generates radiation at a wavelength of about 199 nm and at least 200 mW of power with a linewidth of less than 10 GHz," say the applicants. "In another embodiment, narrow linewidth UV light is generated at 265 nm."
• Title: Methods for polarization control of VCSELs
Applicant: Finisar Corporation, US
International patent application number: WO 2005/082010
Adding strain and stress elements into a VCSEL structure is an ideal way to stabilize the source's polarization, according to Finisar in patent application WO 2005/082010. "Stress-inducing features may be formed on the top or bottom surface of a VCSEL, on the side of a VCSEL, or within a VCSEL to produce a break in its symmetry of stresses to effect a polarization influence on the output of the VCSEL," say the authors. A laser beam with stable polarization is desirable for applications such as optical communication.