Disorder-Enhanced Imaging with Spatially Controlled Light

Bibliography 15
for non-imaging displacement metrology.
In chapter 2 we introduce a framework of scattering and transmission matrices,
show how spatial light control is used to measure elements of these matrices,
and we study how this information can be used to control light propagation in
disordered materials under experimental relevant conditions.
The fabrication and characterization of the disordered photonic structures we
developed for our experiments are described in Chapter 3. First we discuss
disordered zinc oxide samples that can be doped with fluorescent nano spheres.
Then we detail the fabrication of high resolution scattering lenses out of gallium
phosphide.
In chapter 4 we experimentally show that spatial wave front shaping can be
used to focus and concentrate light to an optimal small spot inside a turbid
material. Chapter 5 is dedicated to a non-imaging approach of displacement
metrology for disordered materials that opens the way for high speed nanometerscale
position detection.
With scattering lenses made out of gallium phosphide it is possible to achieve
sub-100 nm optical resolution at visible wavelengths using the high refractive index
of the material; High Index Resolution Enhancement by Scattering (HIRES).
In chapter 6 we combine such HIRES scattering lens with spatial wave front shaping
to generate a small scanning spot with which we image gold nano spheres.
While the resolution of the HIRES scattering lens is very high, the obtained
field of view is restricted by the optical memory effect to a few square micrometers.
To use these scattering lens in wide field mode we developed a new imaging
technique that exploits correlations in scattered light; Speckle Correlation Resolution
Enhancement (SCORE). Chapter 7 starts with a theoretical consideration
of SCORE supported by simulations. In the second part of that chapter we describe
an experiment where SCORE is used to acquire high resolution wide field
images of fluorescent nano spheres that reside in the object plane of a gallium
phosphide scattering lens.
The developed imaging technique SCORE is more general applicable to scattering
lenses. In chapter 8 we demonstrate that with a proof of principle of reference
free imaging through opaque disordered materials. This technique promises to
be of great relevance to biomedical imaging, transportation safety, and detection
of concealed weapons.
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