Electrooptics group

 

Under the broad title of ‘nanophotonics and photonic components’, researchers use both theoretical and experimental approaches to explore interferometry, fundamentals and applications of periodic structures, quantum cryptography, and display systems.The Electrooptics Group has developed a heterodyne interferometer, which is designed to measure phase and absolute amplitude in the entire frequency range 0-1.0 GHz. Its transverse resolution is <1 μm while the present sensitivity for vibrations is ~1 pm/Hz1/2. The heterodyne interferometer is a valuable tool for the characterization of vibrating micro- and nanostructures, and for quality control in the conception, design and manufacturing of new acoustic devices.Another ongoing research project is the development of a device for optical readout of ultrasonic waves using periodic structures. Photonic crystal structures are being investigated with respect to their dispersive properties and nonlinear optical effects, combined with the possibility to reduce dimensions of optical components. By arranging two materials with different dielectric constants in a periodic pattern, a photonic bandgap (PBG) can be defined consisting of allowed and forbidden electron energy bands. Spectral tuning is controlled by the symmetry and lattice spacing of the PBG structures.Researchers are also examining speckle reduction techniques to reduce speckle contrast in laser display systems. This project explores both existing and newly created approaches, with the end goal the construction of a modulator based on the most promising speckle reduction method.The Electrooptics Group is also actively involved in quantum cryptography, in particular security issues. Existing systems are hacked to demonstrate loopholes, modifications are suggested, and security proofs are developed to cover realistic systems. In August 2010, NTNU scientists, along with colleagues at the University of Erlangen-Nürnberg and the Max Planck Institute for the Science of Light were able to exploit imperfections in a quantum cryptography system to remotely control the photon detector, a key component in most quantum cryptography systems. The results of this effort were published in Nature Photonics. lab_interferomi_200x200

  (Astrid Aksnes/Johannes Skaar)

Nanoelectronics and Photonics group web page