Striae-free chalcogenide glasses

1. A method to synthesize striae-free chalcogenide glass using melt processing, comprising the steps of:

melting chalcogenide glass inside a sealed silica ampoule;

providing a 2-zone furnace comprising an upper zone and a lower zone wherein the upper zone is at a higher temperature than the lower zone and wherein the zones are independently controllable temperature zones;

mixing by rocking the sealed silica ampoule inside the 2-zone furnace;

placing the sealed silica ampoule in a vertical position;

forming a glass melt as the upper zone is at a higher temperature than the lower zone;

positioning the glass melt such that the glass melt is within the lower zone; and

cooling slowly and quenching the temperature;

reducing the temperature of the upper zone at a rate of 0.6° C./min to 370° C.;

reducing the temperatures of the lower zone at a rate of 0.6° C./min to 260° C.;

holding these temperatures for 12 hours; and thereby

forming the striae-free chalcogenide glass.

2. The method to synthesize striae-free chalcogenide glass using melt processing of claim 1 , further comprising the step of preventing convection currents within the glass melt as the glass melt solidifies forming the chalcogenide glass.

3. The method to synthesize striae-free chalcogenide glass using melt processing of claim 2 , further comprising the step of preventing condensation of glass on the ampoule as the glass melt cools.

4. The method to synthesize striae-free chalcogenide glass using melt processing of claim 1 , further comprising the steps of:

allowing for an initial melting of the chalcogenide glass prior to the step of mixing by rocking; and

allowing for homogenization of the chalcogenide glass.

5. The method to synthesize striae-free chalcogenide glass using melt processing of claim 4 , further comprising the step of avoiding abrasion of the ampoule during the rocking step.

6. The method to synthesize striae-free chalcogenide glass using melt processing of claim 1 , further comprising the steps of:

maintaining the temperature of the lower zone at a temperature of about 700° C. for about 24 hours; and

maintaining the temperature of the upper zone at a temperature of about 100° C. greater than the temperature of the lower zone for about 24 hours.

7. A method to synthesize striae-free chalcogenide glass using melt processing, comprising the steps of:

loading arsenic and sulfur precursors sufficient to constitute a 120 gram batch of glass with the composition of 39% at. arsenic (As) and 61% at. sulphur (S) or about 71.88 grams As and 48.12 grams S into a silica ampoule under an inert gas atmosphere;

connecting the ampoule to a vacuum pump;

evacuating the ampoule for 4 hours at 1×10 −5 Torr;

sealing the ampoule;

placing the ampoule inside a rocking furnace with a ±45° angle of inclination wherein the furnace has a top zone and a bottom zone and wherein the zones are independently controllable temperature zones;

heating and rocking the ampoule;

heating the top zone and the bottom zone of the furnace at a rate of 3° C./min from room temperature;

heating the top zone to 850° C.;

heating the bottom zone to 750° C.;

holding constant the temperature of the top zone (850° C.) and bottom zone (750° C.) for 10 hours;

rocking the furnace at an inclination angle of ±45° to facilitate mixing and homogenization of the elemental components;

stopping the furnace motion;

setting the furnace to a vertical position or 90° fixed angle;

decreasing the temperature of the top zone at a rate of 1° C./min to 800° C.;

decreasing the temperature of the bottom zone at a rate of 1° C./min to 700° C.;

holding the furnace position and temperature profile for 24 hours to facilitate fining and settling of the glass melt;

reducing the temperature of the top zone at a rate of 0.6° C./min to 370° C.;

reducing the temperatures of the bottom zone at a rate of 0.6° C./min to 260° C.;

holding these temperatures for 12 hours;

forming a chalcogenide glass;

removing the ampoule from the furnace;

submerging the ampoule in a room temperature water bath for 10 seconds to quench the chalcogenide glass;

annealing the chalcogenide glass by placing the ampoule in another furnace at 180° C. for 10 hours; and

forming a striae-free chalcogenide glass.