Mirror coupling

1. A device comprising:

a shaft defining a rotational axis, wherein the shaft comprises a first material having a first coefficient of thermal expansion; and

a rotatable mirror disposed about the shaft, the rotatable mirror comprising:

a multi-sided structure comprising a plurality of exterior surfaces and a plurality of interior surfaces, wherein each exterior surface of the plurality of exterior surfaces is opposite a respective interior surface of the plurality of interior surfaces, wherein the multi-sided structure comprises a second material having a second coefficient of thermal expansion, wherein the second coefficient of thermal expansion is different from the first coefficient of thermal expansion, providing a CTE mismatch;

a plurality of reflective surfaces, wherein each reflective surface of the plurality of reflective surfaces is disposed on a respective exterior surface of the plurality of exterior surfaces of the multi-sided structure; and

one or more support members, each support member comprising (i) two first ends coupled to two different interior surfaces of the plurality of interior surfaces and (ii) a second end coupled to the shaft.

2. The device of claim 1 , wherein the first material comprises steel having a CTE between 11-12.5×10 −6 /K, and wherein the second material comprises polycarbonate having a CTE between 65-70×10 −6 /K.

3. The device of claim 1 , wherein the support members are configured to accommodate a temperature-dependent material expansion or contraction between the shaft and the multi-sided structure.

4. The device of claim 1 , wherein the support members are configured to maintain a temperature-independent flatness of the plurality of reflective surfaces within ±10 microns.

5. The device of claim 1 , wherein the support members are t-shaped.

6. The device of claim 1 , wherein the two first ends of each support member are formed from a different material than the second end.

7. The device of claim 1 , wherein the multi-sided structure is a four-sided structure and wherein the plurality of reflective surfaces comprises four reflective surfaces.

8. The device of claim 1 , wherein each of the reflective surfaces comprises at least one of: titanium, platinum, or aluminum.

9. The device of claim 1 , wherein the multi-sided structure comprises a hollow portion, wherein the shaft is disposed so as to pass through the hollow portion.

10. The device of claim 1 , wherein the first material is steel and the second material is plastic.

11. The device of claim 10 , wherein each reflective surface comprises a deposited material on the multi-sided structure.

12. A system comprising:

a light-emitter device;

a photodetector;

a rotatable mirror disposed about a shaft defining a rotational axis, wherein the shaft comprises a first material having a first coefficient of thermal expansion, wherein the rotatable mirror comprises:

a multi-sided structure comprising a plurality of exterior surfaces and a plurality of interior surfaces, wherein each exterior surface of the plurality of exterior surfaces is opposite a respective interior surface of the plurality of interior surfaces, wherein the multi-sided structure comprises a second material having a second coefficient of thermal expansion, wherein the second coefficient of thermal expansion is different from the first coefficient of thermal expansion, providing a CTE mismatch;

a plurality of reflective surfaces, wherein each reflective surface of the plurality of reflective surfaces is disposed on a respective exterior surface of the plurality of exterior surfaces of the multi-sided structure; and

one or more support members, each support member comprising (i) two first ends coupled to two different interior surfaces of the plurality of interior surfaces and (ii) a second end coupled to the shaft; and

a controller that executes instructions so as to carry out operations, the operations comprising:

causing the rotatable mirror to rotate about the rotational axis; and

causing the light-emitter device to emit light pulses toward at least one reflective surface such that at least a portion of the light pulses interact with an external environment so as to form reflected light pulses.

13. The system of claim 12 , wherein the operations further comprise:

based on receiving, with the photodetector, the reflected light pulses from the external environment by way of the at least one reflective surface, determining at least one of: a point cloud, a range, or a distance.

14. The system of claim 12 , wherein the first material comprises steel having a CTE between 11-12.5×10 −6 /K, and wherein the second material comprises polycarbonate having a CTE between 65-70×10 −6 /K.

15. The system of claim 12 , wherein the support members are configured to accommodate a temperature-dependent material expansion or contraction between the shaft and the multi-sided structure.

16. The system of claim 12 , wherein the support members are configured to maintain a temperature-independent flatness of the plurality of reflective surfaces within ±10 microns.

17. The system of claim 12 , wherein the support members are t-shaped straight.

18. The system of claim 12 , wherein the two first ends of each support member are formed from a different material than the second end.

19. The system of claim 12 , wherein the multi-sided structure is a four-sided structure and wherein the plurality of reflective surfaces comprises four reflective surfaces, wherein the reflective surfaces comprise at least one of: titanium, platinum, or aluminum.

20. The system of claim 12 , wherein the multi-sided structure comprises a hollow portion, wherein the shaft is disposed so as to pass through the hollow portion.

21. The system of claim 12 , wherein the first material is steel and the second material is plastic.

22. The system of claim 21 , wherein each reflective surface comprises a deposited material on the multi-sided structure.