Phosphate glass useful in high power lasers

• US 4,929,387 A
• Filed: 04/03/1989
• Issued: 05/29/1990
• Est. Priority Date: 08/31/1988
• Status: Expired due to Term

• Current Assignee: Schott Glass Technologies Incorporated Duryea PA 18642
• Original Assignee: Schott Glass Technologies, Inc.
• Inventors: Hayden, Joseph S., Sapak, David L., Ward, Julia M.
• Primary Examiner(s): BELL, MARK LEE
• Application Number:
  US07/331,782
• Time in Patent Office: 421 Days
• Field of Search: 252/301.4 P, 252/301.6 P, 501/45, 501/47, 501/48, 501/73, 501/78
• US Class Current: 252/301.40P
• CPC Class Codes: C03C 3/064 containing boron
• CPC Class Codes: C03C 3/17 containing aluminium or beryllium
• CPC Class Codes: C03C 3/19 containing boron
• CPC Class Codes: C03C 4/0071 for laserable glass
• CPC Class Codes: H01S 3/17 amorphous, e.g. glass

Abstract

A low- or no-silica phosphate glass useful as a laser medium and having a high thermal conductivity, K₉₀° C. >0.8 W/mK, and a low coefficient of thermal expansion, α₂₀°-40° C. <80×10^-7 /°C., consists essentially of (on a batch composition basis):

______________________________________                                    

Mole % ______________________________________ P₂ O₅ 45-70 Li₂ O 15-35 Na₂ O 0-10 Al₂ O₃ 10-15 Nd₂ O₃ 0.01-6 La₂ O₃ 0-6 SiO₂ 0-8 B₂ O₃ 0-8 MgO 0-18 CaO 0-15 SrO 0-9 BaO 0-9 ZnO 0-15 ______________________________________

the amounts of Li₂ O and Na₂ O providing an average alkali metal ionic radius sufficiently low whereby said glass has K₉₀° C. >0.8 W/mK and α₂₀°-40° C. <80×10^-7 /°C., and wherein, when the batch composition is melted in contact with a silica-containing surface, the final glass composition contains at most about 3.5 mole % of additional silica derived from such contact during melting. The Nd₂ O₃ can be replaced by other lasing species.

Claims

1. A low- or no-silica phosphate glass useful as a laser medium and having a high thermal conductivity, K₉₀°

C. >

0.8 W/mK, and a low coefficient of thermal expansion, α

₂₀°

-40°

C. <

80×

10^-7 /°

C., consisting essentially of (on a batch composition basis);

space="preserve" listing-type="tabular">______________________________________ Mole % ______________________________________ P.sub.2 O.sub.5 45-70 Li.sub.2 O 15-35 Na.sub.2 O 0-10 Al.sub.2 O.sub.3 10-15 K.sub.2 O 0-3 lasable ion 0.01-6 La.sub.2 O.sub.3 0-6 SiO.sub.2 0-8 B.sub.2 O.sub.3 0-8 MgO 0-18 CaO 0-15 SrO 0-9 Bao 0-9 ZnO 0-15 ______________________________________

the amounts of Li₂ O and Na₂ O providing an average alkali metal ionic radius sufficiently low whereby said glass has K₉₀°

C. >

0.8 W/mK and α

₂₀°

-40°

C. <

80×

10^-7 /°

C., and wherein, when the batch composition is melted in contact with a silica-containing surface, the final glass composition contains at most about 3.5 mole % of additional silica derived from such contact during melting.

2. A glass of claim 1, wherein said lasable ion is a lanthanide.

3. A glass of claim 2, wherein an amount of La₂ O₃ replaces a portion of said amount of said lasable ion.

4. A glass of claim 2, wherein said lasable ion is Nd.

5. A glass of claim 4, consisting essentially of (on a batch composition basis)

6. A class of claim 4, consisting essentially of (on a batch composition basis)

7. A glass of claim 4, consisting essentially of (on a batch composition basis)

8. A glass of claim 5, wherein K₉₀°

C. ≧

0.85 and α

₂₀°

-40°

C. <

77.

9. A glass of claim 5, wherein the content of MgO is 4-15 mole %.

10. A glass of claim 1 further containing an effective amount of a refining agent or another batch component effective as a solarization inhibitor, excluding SiO₂.

11. A glass of claim 1, wherein the content of MgO is 4-15 mole %.

12. A glass of claim 1 containing essentially no alkali metal oxides other than Li₂ O.

13. A glass of claim 5 containing essentially no alkali metal oxides other than Li₂ O.

14. A glass of claim 6 containing essentially no alkali metal oxides other than Li₂ O.

15. A glass of claim 1, wherein said lasable ion is Tm, Yb, Dy, Pm, Tb, Er, Ho, Ti, V, Cr, Eu, or Sm.

16. A glass of claim 1 which further contains an amount of a transition metal or lanthanide dopant ion effective to transfer energy to said lasing ion.

17. In a laser comprising a cavity having an active glass component and reflective end surfaces, the improvement wherein said glass is one of claim 1.

18. A laser of claim 17, wherein said active glass component is chemically strengthened by ion exchange.

20. A glass of claim 1 containing essentially no SiO₂ in the batch composition and up to 3 mole % SiO₂ in the final glass composition.

21. A glass of claim 1 containing essentially no SiO₂ in the batch composition and up to 2 mole % SiO₂ in the final glass composition.

22. A glass of claim 1, melted in a non-SiO₂ containing crucible.

23. A glass of claim 1, having the following properties:

space="preserve" listing-type="tabular">______________________________________ Damaging inclusions per liter essentially zero Strengthenability ≧

4 x Young'"'"'s Modulus (E) <

72 ×

10.sup.3 N/mm.sup.2 Poisson'"'"'s Ratio (ν

) <

0.230 Cross section (σ

) >

3.5 ×

10.sup.-20 cm.sup.2 Fluorescence lifetime (5% Nd) >

250 μ

sec. ______________________________________

19. A low- or no-silica phosphate glass useful as a laser medium and having a high thermal conductivity, K₉₀°

C. >

0.8 W/mK, and a low coefficient of thermal expansion, α

₂₀°

-40°

C. <

80×

10^-7 /°

C., consisting essentially of (on a batch composition basis);

space="preserve" listing-type="tabular">______________________________________ Mole % ______________________________________ P.sub.2 O.sub.5 45-70 Li.sub.2 O 15-35 Na.sub.2 O 0-10 K.sub.2 O 0 Al.sub.2 O.sub.3 10-15 lasing ion 0-6 La.sub.2 O.sub.3 0-6 SiO.sub.2 0 B.sub.2 O.sub.3 0-8 MgO 0-18 CaO 0-15 SrO 0-9 BaO 0-9 ZnO 0-15 ______________________________________

the amounts of Li₂ O and Na₂ O providing an average alkali metal ionic radius sufficiently low whereby said glass has K₉₀°

C. >

0.8 W/mK and α

₂₀°

-40°

C. <

80×

10^-7 /°

C., and wherein, when the batch composition is melted in contact with a silica-containing surface, the final glass composition contains at most about 3.5 mole % of additional silica derived from such contact during melting.