1. Optical Antennas for Raman Spectroscopy Laura Matloff Mentor: Matteo Staffaroni (EECS) Faculty Sponsor: Prof. Yablonovitch

2. At Airports Compact desktop explosives/narcotics detection system Sample collection swab Security Guy Your check-in luggage

4. nose

5. Pump Photon Target Molecule in Ground State Excited State Pump Photon Ground State Virtual Level Raman Spectroscopy

6. Pump Photon Target Molecule in Excited State Pump Photon Virtual Level Ground State Excited State Stokes-shifted Photon Stokes-shifted Photon Raman Spectroscopy

7. Photon Counts Wavelength (nm) 514524 534544 554 504 Pump Photons The likelihood of a Raman scattering event depends on the intensity of the light in the neighborhood of the molecule

8. Photon Counts Wavelength (nm) 514524 534544 554 504 Pump Photons Stokes-shifted Photons For single molecule detection (E-Field enhancement) 4 > 10 14

9. The Dipole Antenna

10. Antenna Arm Length (µm)

26. Single molecule detection requires electric field enhancement of 10 14 10 16 10 14 10 1210 10 8 10 6 10 4 10 2 1 Optical Antenna Antenna Arm Length (µm)

27. Single molecule detection requires electric field enhancement of 10 14 10 16 10 14 10 1210 10 8 10 6 10 4 10 2 1 Optical Antenna

28. Single molecule detection requires electric field enhancement of 10 14 10 16 10 14 10 1210 10 8 10 6 10 4 10 2 1 Optical Antenna

29. Single molecule detection requires electric field enhancement of 10 14 10 16 10 14 10 1210 10 8 10 6 10 4 10 2 1 Optical Antenna

30. Single molecule detection requires electric field enhancement of 10 14 10 16 10 14 10 1210 10 8 10 6 10 4 10 2 1 Optical Antenna Grating Coupler

31. Grating Coupler

32. COMSOL Model Without GratingWith Grating

35. - + - + Transformer

36. 3D Taper (Optical Transformer) Au

37. Single molecule detection requires electric field enhancement of 10 14 10 16 10 14 10 1210 10 8 10 6 10 4 10 2 1 Optical Antenna Grating Coupler Optical Transformer

38. 2D Taper Au

39. The Side View

40. Initial Thickness Final Thickness Taper Angle Au The Side View

41. Optimizing Taper Angle Power Throughput (%) Taper Angle (Degrees) Where Initial Thickness = 50nm and Final Thickness = 5nm

42. Transformer Action in 2D 100 nm Air 50 nm Final Plate Spacing (nm) V out / V in 1 10

43. Transformer Action in 2D 100 nm Air 50 nm Final Plate Spacing (nm) V out / V in 1 10

44. E-Field Enhancement in 2D E out / E in

45. Transformer Action in 3D V out / V in

46. E-Field Enhancement in 3D E out / E in

47. Single molecule detection requires electric field enhancement of 10 14 10 16 10 14 10 1210 10 8 10 6 10 4 10 2 1 Optical Antenna Grating Coupler Optical Transformer

48. Citations Pictures: http://unitedlp.com/images/power_Lines.jpg www.jamd.com/image/g/1714820 http://www.macsparky.com/wp-content/uploads/2008/01/crowd.jpg