1. II Escuela de Optica Biomedica, Puebla, 2011 Use of polarized light imaging and sensing in the clinical setting Jessica C. Ramella-Roman, PhD

2. II Escuela de Optica Biomedica, Puebla, 2011 Short Bio Laura in Electrical Engineering, University of Pavia, Italy (93) MS and PhD in Electrical Engineering from Oregon Health & Science University (04) – Advisor Steve Jacques – Thesis on use of polarized light in biophotonics Post doc at Johns Hopkins, APL (04,05) – Polarized light interaction with rough surfaces

3. II Escuela de Optica Biomedica, Puebla, 2011 Short Bio cnt. Associate Professor in Biomedical Engineering (05-present) at CUA Adjunct A. Prof. Johns Hopkins School of Medicine (06-present) Guest Researcher NIST (04- present) Research – faculty.cua.edu/ramella – Tissue oximetry, retina, skin using reflectance spectroscopy and MI – Small vessel Flowmetry and structural analysis – Polarized light imaging and sensing for the detection of skin cancer, vascular abnormalities

4. II Escuela de Optica Biomedica, Puebla, 2011 Course outline Lecture 1- Introduction and fundamentals of polarimetry Lecture 2- Experimental Stokes and Mueller matrix polarimetry Lecture 3 – Modeling – Monte Carlo 1 Lecture 4 – Modeling – Monte Carlo 2 Lecture 5 – Clinical applications of polarized light sensing

5. II Escuela de Optica Biomedica, Puebla, 2011 64 Polarized light in bio-photonics Filtering mechanism Skin cancer imaging Imaging of superficial features Vasculature others *JBO 2002

6. II Escuela de Optica Biomedica, Puebla, 2011 53% absorbed ~4% parallel surface glare ~2-4% parallel, sub surface 100% parallel incidence unpolarized40% Epidermis papillary dermis reticular dermis Filtering mechanism 64 x y

7. II Escuela de Optica Biomedica, Puebla, 2011 64 53% absorbed ~4% parallel surface glare ~2-4% parallel, sub surface 100% parallel incidence unpolarized40% Epidermis papillary dermis reticular dermis Filtering mechanism-surface glare 64 x y

8. II Escuela de Optica Biomedica, Puebla, 2011 64 53% absorbed ~4% parallel surface glare ~2-4% parallel, sub surface 100% parallel incidence unpolarized40% Epidermis papillary dermis reticular dermis Filtering mechanism-single scattering Co polarized 64 x y

9. II Escuela de Optica Biomedica, Puebla, 2011 64 53% absorbed ~4% parallel surface glare ~2-4% parallel, sub surface 100% parallel incidence unpolarized40% Epidermis papillary dermis reticular dermis Filtering mechanism-multiple scattering Cross polarized 64 x y

10. II Escuela de Optica Biomedica, Puebla, 2011 64 Polarized light imaging of skin cancer H H & V

11. II Escuela de Optica Biomedica, Puebla, 2011 parper parper - + Polarized image = Par = Superficial + Deep Per = Deep Enhance superficial structures such as skin cancer margins

12. II Escuela de Optica Biomedica, Puebla, 2011 64 Polarized imaging: Basal-Cell Carcinoma Unpolarized Polarized

13. II Escuela de Optica Biomedica, Puebla, 2011 compound nevus 1-cm ruler normal pol

14. II Escuela de Optica Biomedica, Puebla, 2011 freckle normal pol

15. II Escuela de Optica Biomedica, Puebla, 2011 tattoo

16. II Escuela de Optica Biomedica, Puebla, 2011 Imaging of superficial features Polarization signature of roughness Cosmetic industry and rendering community Skin cancer Fresnel Reflection    ii ss Air Skin top surface

17. II Escuela de Optica Biomedica, Puebla, 2011 17 Vasculature enhancement 53% absorbed ~4% parallel surface glare ~2-4% parallel sub surface 100% parallel incidence unpolarized40% capillary transillumination

18. II Escuela de Optica Biomedica, Puebla, 2011 Other techniques that use polarization Mueller matrix imaging - colon cancer – De Martino et al. Opt. Exp. 2011 Polarized light scattering spectroscopy – eliminate multiple scattering with co/cross polarized layout – V. Backman et al. Nature 2001 PS OCT – birefringence / structural components – De Boer, Opt. Exp. 2005 Particle sizing (….)

19. II Escuela de Optica Biomedica, Puebla, 2011 Polarization fundamentals

20. II Escuela de Optica Biomedica, Puebla, 2011 Polarization basics Polarization is a property that arises out of the transverse (and vector) nature of the electromagnetic (EM) radiation It describes the shape and the orientation of the locus of the electric field vector (Ε) extremity as a function of time, at a given point of the space *. * Ghosh et al. JBO 2011

21. II Escuela de Optica Biomedica, Puebla, 2011 Electric Field vector (EM) E ox E oy X Y Z E  x,  y =phases  =light frequency k = 2  /  ox  oy, =magnitude of electric field =wavelength of light in free space

22. II Escuela de Optica Biomedica, Puebla, 2011 Polarization Ellipse 2E 0y  x y

23. II Escuela de Optica Biomedica, Puebla, 2011 Jones vector formalism Advantages: - Measurement of coherence and time dependent phenomena - Speckle based techniques Disadvantage -Cannot handle depolarization  x,  y = phases  ox  oy, = magnitude of electric field

24. II Escuela de Optica Biomedica, Puebla, 2011 Jones matrix Polarized transfer of light – interaction with a medium J is a 2x2 complex matrix

25. II Escuela de Optica Biomedica, Puebla, 2011 Stokes vector formalism Intensity based representation Characterize the polarization state of light E 0x, E 0y, Cartesian electric field component  =  x -  y phase difference

26. II Escuela de Optica Biomedica, Puebla, 2011 Stokes vector formalism Four measurable quantities (intensities) Characterize the polarization state of light G.G. Stokes (1852) Advantages: - Handles depolarization - Easy experimental application Disadvantage - Cannot handle coherence

27. II Escuela de Optica Biomedica, Puebla, 2011 Stokes vector formalism Four measurable quantities (intensities) Characterize the polarization state of light G.G. Stokes (1852) Restriction on the Stokes parameters

28. II Escuela de Optica Biomedica, Puebla, 2011 Poincaré sphere A geometrical representation of Stokes vectors Sphere with unit radius Linearly polarized states are on the equator Circularly polarized states are at the poles Partially polarized states are inside the sphere

29. II Escuela de Optica Biomedica, Puebla, 2011 Linearly polarized light = E 0x = E 0y

30. II Escuela de Optica Biomedica, Puebla, 2011 Linearly polarized light = E 0x = E 0y

31. II Escuela de Optica Biomedica, Puebla, 2011 Linearly polarized light

32. II Escuela de Optica Biomedica, Puebla, 2011 Linearly polarized light = -E 0x

33. II Escuela de Optica Biomedica, Puebla, 2011 Circularly polarized light

34. II Escuela de Optica Biomedica, Puebla, 2011 Circularly polarized light

35. II Escuela de Optica Biomedica, Puebla, 2011 Unpolarized light Unpolarized light cannot be described through a Jones vector Stokes vector and Mueller matrix formalism is mostly used in biophotonics

36. II Escuela de Optica Biomedica, Puebla, 2011 Mueller matrix i, input o, output

37. II Escuela de Optica Biomedica, Puebla, 2011 Mueller matrix cnt. i, input o, output Multiple Mueller Matrices M i

38. II Escuela de Optica Biomedica, Puebla, 2011 Scattering matrix Mie theory Spheres, spheroids, cylinders D=0.01µm Scattering must be in reference plane If not Stokes vector must be rotated onto that plane

39. II Escuela de Optica Biomedica, Puebla, 2011 Mueller Matrix from microspheres solutions *Cameron et al. JBO 2001 D= 2µm m11 m44

40. II Escuela de Optica Biomedica, Puebla, 2011 Stokes polarimetry, metrics of interest

41. II Escuela de Optica Biomedica, Puebla, 2011 Net degree of polarization

42. II Escuela de Optica Biomedica, Puebla, 2011 Unpolarized portion of the beam

43. II Escuela de Optica Biomedica, Puebla, 2011 Degree of linear polarization

44. II Escuela de Optica Biomedica, Puebla, 2011 Degree of circular polarization

45. II Escuela de Optica Biomedica, Puebla, 2011 Principal angle of polarization 2E 0y  x y Polarization Ellipse

46. II Escuela de Optica Biomedica, Puebla, 2011 Tomorrow Experimental application of polarimetry Introduction to a typical Stokes vector polarimeter Introduction to a typical Mueller Matrix polarimeter