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Wave optical calculations

Kurzinfo   Theory and computer simulations on light propagation, light scattering in focused fields and optical trapping forces.

Optical traps enable the manipulation of small particles (30nm-3µm) without any mechanical contact. For applications in biology and nano-technology it is important to optimize the particle’s interaction with the light from the trapping beam. In this way they can be used as a probe for scanning their local environment. Whereas dielectric materials have the advantage of not absorbing energy, semi-conductor materials and metals are attractive since they show non-linear and resonant behavior. This leads to stronger optical forces and torques inside the trap. In addition, the engineering of new field and intensity distributions will enable new applications not only for trapping and tracking, but also in high-resolution microscopy.

We perform electromagnetic field calculations and simulations to investigate novel configurations for optical trapping of tiny particles, but also to find new interferometric tracking methods for them.
Next steps will be to consider plasmon and exciton resonances in metals and semiconductors as well as new beam modes, such as helical or self-reconstructing beams or beams with mixed polarization states.

Long experience in software development:
Simulation software LightWave 1.1:

- Arbitrary focusing of vectorial electromagnetic fields
- Propagation through homogeneous and inhomogeneous media
- Scattering of arbitrary fields at spheres (extended Mie-theory) and at asymmetric dielectric particles (extended Rayleigh-Gans-theory)
- Optical forces on dielectric particles in arbitrary fields
- Interference patterns and position signals from particles obtained by back-focal plane interferometry
- Imaging of various model objects with arbitrary focus distributions


(x-y-plane) (x-z-plane)
left: Scattering behind a nano-cylinderright: Scattering of gaussian beam at a sphere with D=l/2





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