Klaus D Hachfeld

US Patent:

6486949, Nov 26, 2002

Filed:

Mar 9, 2001

Appl. No.:

09/803281

Inventors:

Klaus D. Hachfeld - Sturbridge MA
Leonid D. Klebanov - Sturbridge MA

Assignee:

Corning Incorporated - Corning NY

International Classification:

G01N 2164

US Classification:

356318, 2504581

Abstract:

A method for evaluating the quality of an optical material includes obtaining a fluorescence spectrum of the optical material, obtaining a fluorescence spectrum of a reference material having desired performance in a target application, and determining whether a shape of the spectrum of the optical material is similar to a shape of the spectrum of the reference material. If the shape of the spectrum of the optical material is similar to the shape of the spectrum of the reference material, the method includes indicating that the optical material is suitable for the target application; otherwise, the method includes indicating that the optical material is unsuitable for the target application.

US Patent:

49493582, Aug 14, 1990

Filed:

Apr 25, 1988

Appl. No.:

7/185864

Inventors:

Joseph W. Kantorski - Southbridge MA
Klaus Hachfeld - Sturbridge MA
James L. Hobart - Los Altos Hills CA

Assignee:

Coherent, Inc. - Palo Alto CA

International Classification:

H01S 3083

US Classification:

372 94

Abstract:

A rod laser having a ring cavity configuration, and including a polarization rotator to compensate for birefringence of the laser's rod. Preferably, the rotator is a 90. degree. crystal quartz rotator. In a preferred embodiment, the ring laser is a stable quasi-unidirectional, non-confocal solid state ring laser. A telescope, including at least two lenses with variable inter-lens spacing, is preferably positioned in the laser beam path as closely as possible to the laser rod. The spacing between the telescope lenses is preferably controlled by a servo mechanism. In a preferred embodiment, a power density detector is provided for producing a beam power signal, and a means (which may include a microprocessor) coupled to the power density detector generates a servo mechanism feedback control signal from the beam power signal. Since the system of the invention maintains a high quality output beam having low far-field beam divergence and small laser beam focal spot diameter, over a wide and varying range of output beam power, the output beam is particularly useful for such applications as high speed drilling, welding, and cutting.