Presentation at FOM Veldhoven, a national physics conference

1. Speckle correlation functions applied to surface plasmons Frerik van Beijnum Jeroen Sirre Chris Rétif (AMOLF) Martin van Exter

2. Speckle correlation functions applied to surface plasmons

3. What is a speckle correlation function? λ = 532 nm, C=1 λ = 633 nm, C=0

4. What is a speckle correlation function? λ = 532 nm, C=1 λ = 633 nm, C=0 Averaged change of speckle pattern as a function of wavelength or angle

5. The traditional speckle correlation function 3D medium: slab of strongly scattering particles PRL 64, 2788 (1990)

6. The traditional speckle correlation function 3D medium: slab of strongly scattering particles PRL 64, 2788 (1990) Compared to the complexity of the disorder the correlation function is simple

7. Speckle correlation functions applied to surface plasmons

8. A surface plasmon polariton (SPP) Image from: Nature 424, 824 (2004) Surface wave Suffers from absorption, propagates typically 10-50 µm Subwavelength holes excite surface plasmons

9. Surface plasmons in ordered systems - holes excite surface plasmons - direct transmission - More than ten years of research to understand and apply extraordinary optical transmission Nature 391, 667 (1998)

10. Surface plasmons in ordered systems - holes excite surface plasmons - direct transmission - More than ten years of research to understand and apply extraordinary optical transmission Nature 391, 667 (1998) Compared to the simplicity of the structure the understanding the transmission spectrum is complicated

11. How to apply correlation functions to surface plasmons? Interesting and new: two transmission processes, direct (black) and surface plasmon assisted (red)

12. Are speckles seen in transmission? Very faint speckle pattern Intensity normalized to peak transmission OL 36, 3666 (2011)

13. Does the speckle change with wavelength?

14. Does the speckle change with wavelength?

15. Does the speckle change with wavelength?

16. Why do the speckles only change slightly? Different result than for 3D media

17. How does the speckle correlation function change with hole density?

18. Surface plasmon contribution increases with density

19. Simple model for correlation function Distance between holes hole i hole j

20. Simple model for correlation function scattering loss hole i hole j

21. Simple model for correlation function absorption hole i hole j

22. Simple model for correlation function phase acquired hole i hole j

23. Simple model for correlation function hole i hole j

24. Correlation width can be separated in scattering and absorption Scattering reduces the propagation length by a factor 5 Measured cross section is roughly a fifth of the hole diameter Absorption agrees with theory

25. The plasmon contribution vanishes at low density One parameter fit describes data Last data point deviates again. Deviations from model are expected at high densities (hole per squared wavelength).