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Method and apparatus for adding metals to fused silica

Imported: 24 Feb '17 | Published: 06 Jan '04

William P. Peters, Merrill F. Sproul, Daniel R. Sempolinski, Michael H. Wasilewski

USPTO - Utility Patents

Abstract

Methods and apparatus for adding metals such as aluminum to fused silica glass articles are disclosed. The methods and apparatus allow for controlled, low level addition of metals into fused silica glass articles. The fused silica glass articles containing added aluminum exhibit improved internal transmission and decreased absorption change when irradiated with a laser.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing of a furnace used to produce fused silica glass in accordance with one embodiment of the present invention;

FIG. 2 is a schematic drawing of a dopant delivery system for adding dopants to fused silica glass according to one embodiment of the invention; and

FIG. 3 is a graph of aluminum level in a fused silica glass article versus temperature according to one embodiment of the present invention.

Claims

1. A method of fabricating a bulk aluminum-doped fused silica glass article, the method comprising the steps of:

2. The method of claim 1, further comprising the step of heating the second gas stream to a first temperature, heating the precursor to a second temperature to sublimate the precursor, and maintaining the temperature of the saturated, aluminum dopant-containing gas stream at a third temperature.

3. The method of claim 1, wherein the precursor is an organometallic chelate.

4. The method of claim 3, wherein the precursor is a nonhydrolyzable organometallic chelate.

5. The method of claim 3, wherein the organometallic chelate includes aluminum acetylacetonate.

6. The method of claim 1, wherein aluminum is present in the fused silica optical member in a concentration between 100 ppb and 900 ppb.

7. The method of claim 5, wherein the precursor is aluminum acetylacetonate, and wherein the first temperature is between 100° C. to 160° C., the second temperature is between 0° C. and 10° C. below the first temperature, and the third temperature is greater than 175° C.

8. The method of claim 1, further comprising the step of cooling the consolidated glass body from a temperature of greater than 1800° C. to a temperature less than 1200° C. over a time period greater than four hours.