I work at the Sterrewacht Leiden on various astronomical instrumentation projects.
Research interests:
-astronomical polarimetry: new concepts, new instruments, new science
-(exo)planetary atmosphere characterization
-solar and stellar magnetic fields
Current projects:
-The polarimetric mode for EPICS, the planet-finder for the ~40-m E-ELT.
-New polarimetric techniques for exoplanet detection/characterization with VLT/NaCO and HARPSpol.
-Observations of Venus-as-an-exoplanet.
-A broadband apodizing phase plate based on polarization tricks.
-Error budgeting tools for polarimeter development.
-SPEX instrument for aerosol characterization in planetary atmospheres. SPEX is based on spectral modulation of linear polarization (patented).
-A ground-based SPEX for RIVM.
-A Lunar Observatory for Unresolved Polarimetry of Earth (LOUPE).
-Design of a full-Stokes polarimeter for VLT/X-shooter, consisting of a polychromatic modulator spanning 300--2500 nm.
-Circular polarimetry as a remote sensing biomarker.
-HARPS upgrade to spectropolarimeter for measurements of stellar magnetic fields (publication).
-S5T, a compact synoptic telescope to characterize turbulent magnetic fields on the sun; prototype, full instrument.
-Generic lab-polarimeter/ellipsometer.
Some more info here.
I am Working Group leader Instrumentation of the COST network "polarization as a tool to study the solar system and beyond"
Most of my publications can be found here: ADS
Out soon: Frans Snik & Christoph Keller (2012) `Astronomical Polarimetry' in: `Planets, Stars & Stellar Systems' (Springer)
On Oct 26, 2009 I succesfully defended my thesis, which can be dowloaded here.