01 Jul 2003
The pick of this week’s patent applications including a method to detect lead contaminants in calcium fluoride crystals.
• Title: UV optical fluoride crystal elements for <200nm laser lithography and methods therefore
Applicant: Corning Incorporated, US
International application number: WO 03/052392
Corning is trying to patent a method of detecting lead impurities in calcium fluoride crystals which are used to create ultraviolet optics. By measuring the transmission of 200 to 210 nm light through the crystal, the authors say they can determine the proportion of lead to less than 500 ppb. They add that this method will lead to improved manufacturing of optical components that transmit light below 200nm.
• Title: Diode-pumped visible wavelength alkali laser
Applicant: William F Krupke, US
International application number: WO 03/052891
Patent application WO 03/052891 describes two versions of a diode-pumped alkali laser (DPAL). The basic set-up emits in the near infrared and uses a single pump diode to excite atoms in an alkali vapor. The second version emits in the blue and near UV between 323 and 460 nm and relies on a two-step excitation and up-conversion process. “This efficiently sums the energy of two, near infrared diode pump photons in alkali vapor atoms, followed by stimulated emission to their electronic ground levels,” say the inventors.
• Title: LED using diffraction grating
Applicant: Emcore Corporation, US
International application number: WO 03/053107
Emcore is trying to patent an LED design that it says enhances the quantum efficiency of the device. Crucially, the enhanced LED has a reflective diffraction grating on the bottom surface of the substrate. “Emitted light passing downwards through the substrate is diffracted outwards toward the edges of the substrate and passses out of the die through the edges,” say the authors.
Jacqueline Hewett is news reporter on Optics.org and Opto & Laser Europe magazine.