Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
Allard Mosk
Universiteit Twente
Scattering Lens
Allard Mosk (APM) Complex Photonic Systems
MESA+, Universiteit Twente, The Netherlands
Why you can see sharper through a dirty window.
Transmission Coefficients
Eq. (1) of M.Sc. thesis APM (1994)
APM, Nieuwenhuizen & Barnes, PRB (1996)
Soukoulis & Economou Conductance Formula
Coworkers Elbert van Putten
Duygu Akbulut
Hasan Yilmaz
Thomas Huisman
Willem Vos
Jacopo Bertolotti -U. Florence & COPS
Ad Lagendijk - AMOLF & COPS
Jochen Aulbach - AMOLF & ESPCI Paris
Bergin Gjonaj - AMOLF
Kobus Kuipers - AMOLF
Patrick Johnson - AMOLF
Ivo Vellekoop - Recently @ CalTech
Frerik van Beijnum - Now at U. Leiden
Multiple Scattering Elastic scattering: random unitary transformation.
S Diffuse speckle through a 10 μm layer of TiO2 pigment.
Opaque Lens
S
Vellekoop & APM, Opt. Lett. 32, 2309 (2007)
measured transmission normalized by average diffuse intensity
How to generate complex field patterns
Spatial amplitude and phase modulation using commercial TN LCDs van Putten, Vellekoop & APM, Appl. Opt. 47, 2076 (2008).
Spatial light modulator (SLM)
Millions of pixels
Group into 1000’s of segments
Intensity and/or phase modulation
with single SLM.
Experimental setup
LCD
Sample: 10 µm layer of TiO2 pigment. Light source: 633 nm HeNe laser. Detection : 1 pixel of CCD camera.
Experimental results
Always a tight, diffraction-limited spot
Vellekoop, Lagendijk & APM, Nat. Photon. 4, 320 (2010)
Application: Hi-Res scattering lens • Gallium Phosphide (GaP)
- High index of refraction: n=3.4
- Transparent large part visible spectrum
- Can be made extremely scattering*
1 cm
GaP
n = 3.4
* Schuurmans, Vanmaekelbergh, van de Lagemaat & Lagendijk, Science (1999)
Scan the focus Use angular correlations in scattered light
(Memory effect)
Feng et al., Phys. Rev. Lett. (1988) Freund et al., Phys. Rev. Lett. (1988)
Vellekoop & Aegerter, Opt. Lett. (2010)
High resolution imaging High quality optics (NA = 1.49) GaP scattering lens
Reference image of gold
nano particles
High resolution image
Conclusion • High Index Resolution Enhancement by Scattering
– First lens with sub-100 nm resolution using visible light.
– Basis for new high-resolution imaging methods
• To do
– Extend to fluorescence and STED imaging
– Use plasmonic structures to improve focal width
– Improve imaging using “4 Pi” microscopy
– Create superoscillating beams
New Postdoc/PhD vacancies
cops.tnw.utwente.nl for all our papers and recent M.Sc/ Ph.D. theses