Engineered Nanosystems

Centre of Excellence in Computational Complex Systems Research


Current projects

Modelling high efficiency light emitters for general lighting
Research area Solid state lighting based on wide bandgap semiconductors and LEDs is expected to provide a viable way to high efficiency (up to 70-80%) lighting solutions in the next 5-10 years. Lighting is the largest single user of electric energy with a 20 % share and large savings in the electrical energy consumption will be possible using led based lighting solutions. Currently, however, the performance of leds is still insufficient for use in general lighting applications and further advances are required.

The research of this project is conducted in collaboration with the newly started 5-year research program, 'High Efficiency Solid State Lighting Enabled by New Technologies' (HighLight), Department of Micro and Nanosciences, TKK. The HighLight program concentrates on the development of high efficiency led structures for general illumination.
Researchers Jukka Tulkki, Professor
Jani Oksanen, Dr.Tech., Senior Researcher
Oskari Heikkilä, M.Sc., Researcher
References 2008

Research on quantum optics
Research area Usually photon detection statistics of the electro-magnetic field are calculated assuming the field to remain unchanged by the photon measurement process. In high intensity fields the changes may be ignored but in low intensity fields the measurement back action to the electro-magnetic field must be taken into account. An appropriate interpretation of this phenomenon is related to the fundamental quantum measurement theory.

The instantaneous changes in quantum systems are modelled using the quantum jump superoperators. The quantum jumps may produce interesting phenomena. For example with suitable initial conditions for the electro-magnetic field an absorption process can increase the expectation value of the number of the photons in the field.

Currently we are investigating how interference and correlation may be used in optical detection. We are modelling the detection of photons with small group of detectors and trying to calculate the correlation of the output signals.
Researchers Jukka Tulkki, Professor
Teppo Häyrynen, M.Sc., Researcher
References 2008

Department of Biomedical Engineering and Computational Science
Helsinki University of Technology
P.O.Box 9203, FIN-02015 TKK, Finland