17 Dec 2002
The pick of this week's hottest patent applications including a garnet-based phosphor for white-light sources.
• Title: Calcium gallium sulphide (CaGa2S4) as a high gain erbium host
Applicant: BAE Systems Information Electronic Systems Integration, US
International application number: WO 02/099981
A crystal host structure that increases the distance between active doping ions could hold the key to minimizing unwanted effects such as parasitic upconversion and lifetime quenching. The authors of patent WO 02/099981 say their structure allows much more concentrated erbium doping without adverse effects. The inventors add that the host has long excited-state-lifetimes making it an effective energy storage medium for pulsed-laser applications.
• Title: Broad-spectrum terbium-containing garnet phosphors and white-light sources incorporating the same
Applicant: GELcore, US
International application number: WO 02/099902
A phosphor being patented by GELcore could find uses in white-light sources. The garnet phosphor, which contains terbium and rare-earth ions, absorbs in the near UV to blue region and emits from 490 nm to 770 nm. The company says that a light source combining a UV/blue LED and the phosphor can provide white light that may be useful for general illumination.
• Title: Photodynamic therapy lamp
Applicant: Photocure ASA, Norway
International application number: WO 02/098508
An LED-based photodynamic therapy lamp is described in international patent application WO 02/098508. The lamp uses two LED arrays emitting between 630 - 640 nm. The LEDs are arranged in a honeycomb pattern within each array. A single lens placed beneath every LED shapes its output into a parallel and narrow beam. A diffuser is mounted beneath the lenses.
• Title: Method and method for holographic recording of fast phenomena
Applicant: California Institute of Technology, US
International application number: WO 02/099541
US scientists are trying to patent a holographic method for recording fast phenomena. The invention makes use of a recording material that has sufficient sensitivity to reliably record a frame with a single optical pulse. Specially designed hardware generates two pulse-streams which act as object and reference beams. One illuminates the object before striking the recording medium while the other is sent directly to recording medium. Multiplexing the resultant holograms gives the team the ability to view the frames as a movie. "We experimentally demonstrate the system by making movies of laser-induced shock waves with a temporal resolution of 5.9 ns, limited by the pulse width of the Q-switched Nd:YAG laser used in the experiments," say the authors in their patent.
Jacqueline Hewett is news reporter on Optics.org and Opto & Laser Europe magazine.