Diamond optical component for an optical tool

1. A component for an optical probe, the component comprising:

a tubular body defining an internal channel and an opening;

a mounting ring which is mounted within the internal channel and configured to define an aperture aligned with the opening; and

a window disposed across the aperture and bonded to the mounting ring around the aperture,

wherein the window is diamond,

wherein the mounting ring comprises a material having a coefficient of linear thermal expansion a of 14.0×10 −6 K −1 or less at 20° C. and a thermal conductivity of 60 Wm −1 K −1 or more at 20° C.,

wherein the tubular body is made of a chemically inert material, and

wherein the tubular body comprises an internally tapered end portion, the mounting ring comprises an internal taper for receiving an optical fibre, and the mounting ring is press-fit into the tapered end portion.

2. A component according to claim 1 , wherein a is one of: 12.0×10 −6 K −1 or less; 10.0×10 −6 K −1 or less; 8.0×10 −6 K −1 or less; 6.0×10 −6 K −1 or less; and 4.0×10 −6 K −1 or less.

3. A component according to claim 1 , wherein the thermal conductivity is one of: 60 Wm −1 K −1 or more; 80 Wm −1 K −1 or more; 100 Wm −1 K −1 or more; 120 Wm −1 K −1 or more; and 140 Wm −1 K −1 or more.

4. A component according to claim 1 , wherein the material of the mounting ring comprises one or more of molybdenum, chromium, tungsten, nickel, rhodium, ruthenium, diamond, silicon carbide (SiC), tungsten carbide (WC), aluminium nitride (AIN), titanium zirconium molybdenium (TZM), tungsten nickel iron (WNiFe), and tungsten nickel copper (WNiCu).

5. A component according to claim 1 , wherein the mounting ring is formed of molybdenum.

6. A component according to claim 1 , wherein the mounting ring is coated with a chemically inert material around the diamond window within the opening.

7. A component according to claim 1 , wherein the tubular body comprises an end portion which extends beyond the diamond window to protect the diamond window from damage in use.

8. A component according to claim 1 , wherein the end portion comprises a plurality of projections which extend beyond the diamond window with openings therebetween.

9. A component according to claim 1 , wherein the diamond is a diamond material having an absorption coefficient β equal to or less than 0.1 cm −1 , 0.05 cm −1 , 0.01 cm −1 , 0.005 cm −1 , or 0.001 cm −1 at an operating wavelength of the optical probe.

10. A component according to claim 9 , wherein the diamond material has an absorption coefficient β equal to or less than 0.1 cm −1 , 0.05 cm −1 , 0.01 cm −1 , 0.005 cm −1 , or 0.001 cm −1 at an operating wavelength in a mid-infrared range.

11. A component according to claim 1 , wherein the diamond window is free of antireflective coating in an area across the aperture.

12. A component according to claim 1 , wherein an inert metal braze join is provided between the diamond window and the mounting ring.

13. A component according to claim 12 , wherein the inert metal braze join comprises gold and/or tantalum.

14. A component according to claim 12 , wherein a metallization coating is provided on the diamond window between the diamond window and the inert metal braze join.

15. A component according to claim 14 , wherein the metallization coating comprises a layer of a carbide forming metal.

16. A component according to claim 15 , wherein the metallization coating further comprises an inert metal barrier layer between the layer of carbide forming metal and the braze join.