Integrated displacement sensors for probe microscopy and force spectroscopy
In accordance with an embodiment of the invention, there is a force sensor for a probe based instrument. The force sensor can comprise a detection surface and a flexible mechanical structure disposed a first distance above the detection surface so as to form a gap between the flexible mechanical structure and the detection surface, wherein the flexible mechanical structure is configured to deflect upon exposure to an external force, thereby changing the first distance.
1. A force sensor for a probe based instrument, the force sensor comprising:
a detection surface;
an optical diffraction grating disposed on the detection surface;
a flexible mechanical structure disposed a first distance from the detection surface so as to form a gap between the flexible mechanical structure and the detection surface, wherein the flexible mechanical structure is configured to deflect upon exposure to an external force, thereby changing the first distance, the flexible mechanical structure including a reflective surface;
a plurality of probe tips extending outwardly from an outer surface of the flexible mechanical structure;
a light source configured to direct a light beam toward the reflective surface;
at least one optical interferometric sensor configured to sense an intensity of a beam of a diffraction order diffracted by the diffraction grating, wherein the intensity indicates a displacement between the optical diffraction grating and the reflective surface; and
a first electrical connection coupled to the detection surface and a second electrical connection coupled to the flexible mechanical structure, the first electrical connection and the second electrical connection being configured to supply electrostatic forces to actuate the flexible mechanical structure.
2. The force sensor of claim 1 , wherein the plurality of probe tips comprise:
a first probe tip having a first height, the first probe tip being capable of performing a first function; and
a second probe tip having a second height, the second probe tip being capable of performing a second function.
3. The force sensor of claim 2 , wherein the first height is greater than the second height.
4. The force sensor of claim 3 , wherein the first function is imaging and the second function is chosen from non-contact imaging, sensing, surface modification, lithography, and writing data.
5. The force sensor of claim 2 , further comprising a third probe tip having a third height, wherein the first height is greater than the second and third heights.
6. The force sensor of claim 5 , wherein the third probe tip is capable of performing a third function, wherein the first function is imaging and the second and third functions are individually chosen from non-contact imaging, sensing, surface modification, lithography and writing data.
7. The force sensor of claim 2 , wherein the first height is substantially the same as the second height.
8. The force sensor of claim 2 , wherein the first probe tip comprises a different material than the second probe tip.