Super-resolution optical microscopy based on photonic crystal materials

Mickaël Guillaumée

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• Resolution limit of an imaging system:

• High NA : immersion objectives

• Limit: small range of transparent materials with high n

• Near Field Optical Microscopy: collection of evanescent waves (high k//) in

close proximity to the studied sample

• Really high resolution but very slow and not convenient

=> Necessity to find a Far-field technique for nanometre scale

resolution microscopy

Introduction: Optical Microscopy and Diffraction Limit

//

61.0

sin

61.0

effknD

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Imaging through Photonic Crystal Space

Test object

k space collected by the objective

Fourier Transform (FT)

• Principle:

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Imaging through Photonic Crystal Space

Test object

k space collected by the objective

Fourier Transform (FT) Inverse FT of the area inside the circle

• Principle:

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Imaging through Photonic Crystal Space

Test object

k spaces with integer number of K are equivalent

Fourier Transform (FT)

K

N. Le Thomas, R. Houdré et al. Grating-assisted superresolution of slow waves in Fourier space, Physical Review B, 76, 035103 2007

• Principle:

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Imaging through Photonic Crystal Space

Test object

k spaces with integer number of K are equivalent

Fourier Transform (FT) Inverse FT of the area inside the circles

K

• Principle:

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• When spatial filtering with photonic crystal can be considered valid?

• Bloch wave:

• Necessity to get constant to get high spatial frequencies:

=> Achieved for high modulation of RIX

Imaging through Photonic Crystal Space

B. Lombardet, L. A. Dunbar, R. Ferrini, and R. Houdré. Fourier analysis of Bloch wave propagation in photonic crystals, J. Opt. Soc. Am. B, 22, 1179, 2005

First Brillouin zone wave vector

Inverse lattice wave vectors

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From theory to experiment…

• Need for far field imaging: transfer high spatial frequency in free space

=> Image magnification above the diffraction limit should be produced by the

photonic crystal based microscope

• Curved photonic crystal boundary as a magnifying lens:

=> Challenging because refraction highly dependent on frequency and

propagation direction

• Solution: reflecting optics

=> Curvature of the boundary in order to get a magnified image

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Experimental procedure: surface polaritonic crystal

• 2D photonic crystal material replaced by surface polaritonic crystal:

Surface Plasmon Polariton (SPP) wave surface wave propagating at an

interface metal/dielectric

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Experimental procedure: surface polaritonic crystal

• 2D photonic crystal material replaced by surface polaritonic crystal:

Surface Plasmon Polariton (SPP) wave surface wave propagating at an

interface metal/dielectric

Excitation by a periodic structure :

C. Genet and T. W. Ebbesen. Light in tiny holes, Nature 445, 39, 2007

K

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Photonic crystal and SPP: historical information

• Full photonic Band Gap observed for the first time in the visible with SPP

Kitsen, Barnes and Sambles. Full Photonic Band Gap for Surface Modes in the Visible, Physical Review Letters, 77, 2670, 1996

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Experimental procedure

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Experimental procedure

1. Propagation of “SPP Bloch waves” with right excitation condition

2. Reflection on a glycerin droplet boundary acting as an efficient magnifying

mirror (high neff)

3. Image formation at the exit of the “SPP crystal lens” (after the nanohole

array)

4. Scattering of light into free space due to surface roughness (higher in the

image formation area)

5. Collection with a regular microscope

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Experimental results

• High resolution but distortion of the image (image magnification depend on

the object position with respect to the mirror

100nm hole diameter, 40nm distance between hole edges, 500nm period

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Experimental results: biological application

T4 phage virus: 200nm long, 80nm wide T4 phage virus

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Conclusion

• Interesting scientific concept

• Technique has to be improved:

• Image distortion in that configuration

• Control of the mirror

• No theoretical prediction of the microscope resolution

Thank you for your attention.