Graphene sheet and nanomechanical resonator

1. A nanomechanical resonator, comprising:

a support structure;

a graphene sheet at least partially suspended from the support structure, the graphene sheet having a carbon lattice that substantially defines a plane; and

processing electronics including an actuation module having instructions for causing actuation of an actuator, the processing electronics configured to control the actuator to actively control the resonant frequency of a portion of the graphene sheet by applying a variable out-of-plane force to the graphene sheet.

2. The resonator of claim 1 , wherein the actuator is configured to vary the out-of-plane force applied to the graphene sheet and as a result vary an out-of-plane coupling of the graphene to the support structure.

3. The resonator of claim 1 , wherein the graphene sheet comprises a free surface.

4. The resonator of claim 1 , wherein the graphene sheet is fully connected to the support structure.

5. The resonator of claim 1 , wherein the graphene sheet includes a length dimension and a width dimension, and wherein the length dimension is at least three times greater than the width dimension.

6. The resonator of claim 1 , wherein the graphene sheet includes a length dimension and a width dimension, and wherein the length dimension is at least ten times greater than the width dimension.

7. The resonator of claim 6 , wherein the graphene sheet includes a first end and a second end disposed lengthwise opposite the first end, and wherein the graphene sheet is supported at the first end by the support structure.

8. The resonator of claim 7 , wherein the graphene sheet is a cantilever.

9. The resonator of claim 7 , further comprising a second support structure;

wherein the second end of the graphene sheet is supported by the second support structure.

10. The resonator of claim 9 , wherein the graphene sheet forms a bridge over a trench.

11. The resonator of claim 1 , wherein the graphene sheet includes a length dimension and a width dimension, and wherein the length dimension is comparable with the width dimension.

12. The resonator of claim 1 , wherein the graphene sheet is supported by a plurality of supports and wherein the supports are configured to subject the graphene sheet to an in-plane stress field.

13. The resonator of claim 1 , wherein the actuator is configured to vary the out-of-plane force and as a result of varying the out-of-plane force vary a support boundary condition.

14. The resonator of claim 13 , wherein the actuator is configured to vary the support boundary condition and as a result modify the modes of the resonator.

15. The resonator of claim 13 , wherein the actuator is configured to vary the support boundary condition and as a result modify the resonant frequency of the resonator.

16. The resonator of claim 13 , wherein the actuator is configured to vary the support boundary condition and as a result modify the resonant frequency of the resonator.

17. The resonator of claim 13 , wherein the actuator is configured to vary the out-of-plane force and as a result increase coupling between the graphene sheet and at least one support structure.

18. The resonator of claim 13 , wherein the actuator is configured to vary the out-of-plane force and as a result decrease coupling between the graphene sheet and at least one support structure.

19. The resonator of claim 13 , wherein the actuator is configured to vary the out-of-plane force and as a result increase an unsupported length of the graphene sheet.

20. The resonator of claim 13 , wherein the actuator is configured to vary the out-of-plane force and as a result decrease an unsupported length of the graphene sheet.

21. The resonator of claim 13 , wherein the processing electronics are further configured to control the actuator to uniformly vary the out-of-plane force over a width of the graphene sheet.

22. The resonator of claim 13 , wherein the processing electronics are further configured to control the actuator to uniformly vary the out-of-plane force over a perimeter of the graphene sheet.

23. The resonator of claim 13 , wherein the processing electronics are further configured to control the actuator to limit the out-of-plane force to a specified region of the graphene sheet.

24. The resonator of claim 13 , wherein the processing electronics are further configured to control the actuator to limit the out-of-plane force to a plurality of specified regions of the graphene sheet.

25. The resonator of claim 1 , wherein the actuator is configured to electrostatically vary the out-of-plane force.

26. The resonator of claim 1 , wherein the actuator is configured to magnetically vary the out-of-plane force.

27. The resonator of claim 1 , wherein the actuator is configured to vary the out-of-plane force through the application of gas pressure to the graphene sheet.

28. The resonator of claim 1 , wherein the actuator is configured to mechanically vary the out-of-plane force.

29. The resonator of claim 1 , wherein the actuator is configured to change the resonant frequency of the graphene sheet to a target value.

30. A method of controlling the resonant frequency of a suspended graphene nanomechanical resonator, comprising:

providing a support structure;

providing a graphene sheet having a carbon lattice that substantially defines a plane, the graphene sheet at least partially suspended from the support structure; and

controlling, by processing electronics including an actuation module having instructions for causing actuation of an actuator, the actuator to modify the resonant frequency of the graphene by actively varying an out-of-plane force applied to the graphene sheet.

31. The method of claim 30 , further comprising electrostatically varying the out-of-plane force.

32. The method of claim 30 , further comprising magnetically varying the out-of-plane force.

33. The method of claim 30 , further comprising varying the out-of-plane force by applying gas pressure to the graphene sheet.

34. The method of claim 30 , further comprising mechanically varying the out-of-plane force.

35. The method of claim 34 , wherein mechanically varying comprises operating a piezoelectric actuator coupled to a support structure.

36. The method of claim 30 , wherein the controlling step comprises changing the resonant frequency of the graphene sheet to a target value.

37. The method of claim 36 , wherein the controlling step comprises changing the resonant frequency of the graphene sheet to a new value.

38. The method of claim 36 , wherein the controlling step comprises controlling the resonant frequency of the graphene sheet to a reference value in response to an environmental disturbance.

39. The method of claim 30 , further comprising suspending the graphene sheet from the support structure.

40. The method of claim 39 , wherein the suspending comprises supporting the graphene sheet around a perimeter of the graphene sheet.

41. The method of claim 40 , further comprising suspending the graphene sheet from a plurality of support structures.

42. The method of claim 30 , further comprising providing an actuator configured to actively varying an out-of-plane force applied to the graphene sheet.