Optical quality diamond material

Patent metadata

Field	Value
Publication number	US-10125434-B2
Application number	US-201615374071-A
Country	US
Kind code	B2
Filing date	Dec 9, 2016
Priority date	Nov 21, 2002
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

A CVD single crystal diamond material suitable for use in, or as, an optical device or element. It is suitable for use in a wide range of optical applications such as, for example, optical windows, laser windows, optical reflectors, optical refractors and gratings, and etalons. The CVD diamond material is produced by a CVD method in the presence of a controlled low level of nitrogen to control the development of crystal defects and thus achieve a diamond material having key characteristics for optical applications.

First claim

The invention claimed is:

1. A CVD single crystal diamond material comprising:
a low optical birefringence, indicative of low strain, such that when a sample of the material is prepared as an optical plate having a thickness of at least 0.5 mm and measured at room temperature, nominally 20° C., over an area of at least 1.3 mm×1.3 mm, |sin δ|, the modulus of the sine of the phase shift, for at least 98% of the measured area of the sample remains in first order, such that δ does not exceed π/2, and |sin δ| does not exceed 0.9.

2. A CVD single crystal diamond material according to claim 1 , wherein |sin δ| does not exceed 0.9 over 100% of the measured area of the sample.

3. A CVD single crystal diamond material according to claim 1 , wherein |sin δ| does not exceed 0.6 over at least 98% of the measured area of the sample.

4. A CVD single crystal diamond material according to claim 1 , wherein |sin δ| does not exceed 0.6 over at least 100% of the measured area of the sample.

5. A CVD single crystal diamond material according to claim 1 , wherein the diamond material has a single substitutional nitrogen concentration of more than 3×10 15 atoms/cm 3 and less than 5×10 17 atoms/cm 3 as measured by electron paramagnetic resonance (EPR).

6. A CVD single crystal diamond material according to claim 5 , wherein the single substitutional nitrogen concentration is less than 2×10 17 atoms/cm 3 as measured by electron paramagnetic resonance (EPR).

7. A CVD single crystal diamond material according to claim 5 , wherein the single substitutional nitrogen concentration is more than 1×10 16 atoms/cm 3 as measured by electron paramagnetic resonance (EPR).

8. A CVD single crystal diamond material according to claim 1 , comprising a low and uniform optical absorption such that a sample of a specified thickness of at least 0.5 mm has an optical absorption coefficient at a wavelength of 1.06 μm of less than 0.09 cm −1 .

9. A CVD single crystal diamond material comprising:
a low optical birefringence, indicative of low strain, such that when a sample of the material is prepared as an optical plate of at least 0.5 mm thickness and measured at room temperature, nominally 20° C., over a specified area of at least 1.3 mm×1.3 mm, for 98% of the area analysed, the sample remains in first order, δ not exceeding π/2, and a maximum value of Δn [average] , the average value of the difference between the refractive index for light polarised parallel to the slow and fast axes averaged over the sample thickness, does not exceed 1.5×10 −4 .

10. A CVD single crystal diamond material according to claim 9 , wherein Δn [average] does not exceed 1.5×10 −4 over 100% of the measured area of the sample.

11. A CVD single crystal diamond material according to claim 9 , wherein Δn [average] does not exceed 5×10 −5 over 98% of the measured area of the sample.

12. A CVD single crystal diamond material according to claim 9 , wherein Δn [average] does not exceed 5×10 −5 over 100% of the measured area of the sample.

13. A CVD single crystal diamond material according to claim 9 , wherein the diamond material has a single substitutional nitrogen concentration of more than 3×10 15 atoms/cm 3 and less than 5×10 17 atoms/cm 3 as measured by electron paramagnetic resonance (EPR).

14. A CVD single crystal diamond material according to claim 13 , wherein the single substitutional nitrogen concentration is less than 2×10 17 atoms/cm 3 as measured by electron paramagnetic resonance (EPR).

15. A CVD single crystal diamond material according to claim 13 , wherein the single substitutional nitrogen concentration is more than 1×10 16 atoms/cm 3 as measured by electron paramagnetic resonance (EPR).

16. A CVD single crystal diamond material according to claim 9 , comprising a low and uniform optical absorption such that a sample of a specified thickness of at least 0.5 mm has an optical absorption coefficient at a wavelength of 1.06 μm of less than 0.09 cm −1 .

Assignees

• Element Six Tech Ltd

Inventors

• Godfried Herman Philip
• Scarsbrook Geoffrey Alan
• Twitchen Daniel James
• Houwman Evert Pieter
• Nelissen Wilhemus Gertruda Maria
• Whitehead Andrew John
• Hall Clive Edward
• Martineau Philip Maurice

Classifications

• C01B32/26

  Preparation (by using ultra-high pressure B01J3/06; by crystal growth C30B29/04) · CPC title

• C30B25/205

  the substrate being of insulating material · CPC title

• C30B25/02

  Epitaxial-layer growth · CPC title

• C30B19/02

  using molten solvents, e.g. flux · CPC title

• C30B33/12

  in gas atmosphere or plasma · CPC title