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