1. Optical Detection of Micro- Cantilever Deflection Kellen Chase, Richard Colonna, Michael Humphreys, Joseph Ortiz, Grace Shih Dr. Eniko Enikov, AME Dr. Stanley Pau, OSC February 27 th, 2007

2. Agenda Purpose Background Design Progress Questions

3. Statement of Purpose To fabricate an inexpensive optical detection system for a MEMS (micro- electrical mechanical structure) to detect changes in the surface stress of an individual cantilever.

4. Visions Short Term –Utilized in a joint mechanical/optical graduate student laboratory –Students will fabricate and test lithographic masks by attempting to detect an “known” chemical deposited on the cantilever Long Term –Create commercialized product with chemical database to be used outside of an academic setting –Medical use for quick identification of organic compounds

5. Background Chemicals bond to gold –Wet=0º –Dry=30º Surface stress causes power in cantilever –Changes spot centroid Published paper with calibration data –Berger et al., Science, Vol. 276, no. 5321, 2021- 2024, 1997

6. Design Utilize “optical lever” technique –Same principle as atomic force microscopy –Accuracy is determined by separation of Position Sensitive Device (PSD) –Accuracy is limited by PSD active area Subassemblies –Laser –Cantilever –PSD

7. Design

8. Subassembly-Laser

9. Subassembly-Cantilever

10. Subassembly-PSD

11. Procedure Run MATLAB code Align laser, cantilever, & PSD –Adjust 4 DoF on cantilever subassembly –Maximize intensity and center spot on PSD Capture initial PSD reading Deposit chemicals –Secured syringe and tubing Capture final PSD reading

12. Progress Completed Tasks –Have all mechanical & optical parts in lab –Machined and assembled all parts –Obtained array of cantilevers for testing –Acquired chemicals from ChEE Department In Progress –MatLab software code –Circuitry for PSD –Compile lab manual Detailed deposition and alignment techniques

13. Summary of Goals Create inexpensive laboratory apparatus to measure changes in surface stress of micro-cantilevers Uses “optical lever” technique 2 discrete measurements to determine Δσ Possible future uses include: –Organic & non-organic chemical detection

14. Questions http://classes.engr.arizona.edu/engr498a/2006/optomems

15. Members Kellen Chase (520-490-9516) –chased1k@gmail.comchased1k@gmail.com Richard Colonna (520-349-9760) –colonna@email.arizona.educolonna@email.arizona.edu Michael Humphreys (520-603-4762) –michael.r.humphreys@gmail.commichael.r.humphreys@gmail.com Joseph Ortiz (520-250-1826) –jortiz@email.arizona.edujortiz@email.arizona.edu Grace Shih (520-331-1444) –grashi@gmail.comgrashi@gmail.com