Supplementary Information for. Surface Waves. Angelo Angelini, Elsie Barakat, Peter Munzert, Luca Boarino, Natascia De Leo,

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1 Supplementary Information for Focusing and Extraction of Light mediated by Bloch Surface Waves Angelo Angelini, Elsie Barakat, Peter Munzert, Luca Boarino, Natascia De Leo, Emanuele Enrico, Fabrizio Giorgis, Hans Peter Herzig, Candido Fabrizio Pirri, Emiliano Descrovi * 1

2 Supplementary Figures Supplementary Figure S1 Bloch Surface Wave on planar multilayer. (a), calculated reflectivity map R(θ,λ) for the planar multilayer as illuminated at incidence angle θ, by a plane wave having wavelength λ, and TE-polarization (equivalent to s-polarization). The Bloch Surface Waves (BSW) is dispersed according to the low-reflectivity (dark) curve where a narrow resonance dip occurs (inset). At λ=532 nm, the BSW has a spatial frequency calculated as f BSW =λ -1 n s sin(θ)=2.002 µm -1, where n s =1.5 is the refractive index of the glass substrate. (b), calculated cross-sectional intensity profile for a BSW coupled at about θ=45 degrees for λ=532 nm. The vertical axis is normalized to the intensity of the incident wave. 2

3 Supplementary Figure S2 Leakage Radiation Interference Microscope. Sketch of the Mach-Zehnder setup used for the amplitude/phase imaging of the leakage radiation associated to BSW at λ=532 nm. A detailed description of the apparatus is included in the Methods section. 3

4 Supplementary Figure S3 BSW asymmetric focusing. BSW launched and focused by illuminating a portion of the circular grating on a regular multilayer (L=520 nm, D=8 µm), as sketched in Figure 1. (a), intensity distribution superposed to a white light image of the grating. (b), amplitude distribution. (c), phase distribution. A pair of phase dislocations can be observed in the focal region area. All measurements are collected by means of the interference leakage radiation microscope presented in Supplementary Figure S2. 4

5 Supplementary Figure S4 BSW symmetric focusing. Focused BSW launched by illuminating the full circular grating on a regular multilayer (L=520 nm, D=5 µm), as sketched in Figure 1. The BSW is converging towards the center of the ring, where it is focused. The dashed yellow circle indicates the boundary of the inner spacer, therefore the rings are located outside it. All measurements are collected by means of the interference leakage radiation microscope presented in Supplementary Figure S2. (a), real part of the leakage field associated to a BSW coupled from a linearly polarized incident laser (y-direction). (b), real part of the leakage field associated to a BSW coupled from a linearly polarized incident laser (x-direction). (c), real part of the leakage field associated to a BSW coupled from a linearly polarized incident laser (x-direction) and polarizationfiltered with a crossed analyser (y-direction). 5

6 Supplementary Figure S5 Fluorescence imaging systems. (a), Back Focal Plane (BFP) fluorescence imaging system. A focused (Numerical Aperture, NA=0.2) laser beam (λ=532 nm) excites fluorescence on the sample surface. An immersion oil objective (NA=1.49) collects the leakage radiation that is then spectrally filtered. The BFP of the collection objective is imaged onto an RGB camera by means of a tube lens. (b), direct plane fluorescence imaging system. The illumination is an uniform laser distribution obtained by focusing an incoming beam onto the back focal plane of the objective. Fluorescence from the sample is directly imaged onto a monochromatic CCD camera by means of a collection objective (NA=0.2) and a tube lens. (c), same arrangement as in (b), with a focused laser illumination. In all schemes, the polarization of the laser and the collected fluorescence can be controlled through polarizers/analysers. 6

7 Supplementary Figure S6 Polarization-filtered BFP of a flat multilayer. (a), Back Focal Plane image showing fluorescence collected upon local illumination of a flat region on a regular multilayer. A λ=532 nm laser is focused according to the setup in Supplementary Figure S5(a). A rotating polarization analyser is inserted after the collection objective. The resulting BSW-coupled fluorescence is found to be distributed as a pair of bright arcs whose orientation depends on the angular position of the analyser. Here, the polarization is y-oriented and the BSW-coupled arcs are arranged along the x- direction. The corresponding R-channel and G-channel images are separately shown in a row on top of the main figure. 7

8 Supplementary Figure S7 Improving fluorescence beaming on a polymeric circular grating. (a), sketch of a polymeric circular grating fabricated onto a low leakage multilayer. The grating has thickness h=100 nm, diameter D=5 µm and period Λ=520 nm. The polymer is a negative resist Ma-N 2401 (microresist Technology ). (b), Back Focal Plane image showing the fluorescence collected upon local illumination of the flat inner spacer of the polymeric grating. The measurement is performed according to the setup in Supplementary Figure S5(a). The dielectric loading mechanism due to the deposition of the thin polymeric layer produces a redshift for the BSW dispersion such that a wider wavelength range of the dye emission spectrum can be BSW-coupled and then beamed. As a result, a more intense fluorescence beaming can be obtained over a larger spectral range. (c) Cross-sectional distribution of the e.m. field intensity generated by a dipolar emitter located in the inner spacer of the grating. The dipole momentum is parallel to the multilayer surface and oriented normally to the cross-sectional plane. The beaming effect is maximized at a wavelength λ= 600 nm. 8