Optical power limiting
All kinds of light sources interfere with electro-optical sensors and the eye. For sources such as light bulbs and the sun, with low light intensity, the reaction time of the eye is sufficient to protect itself since the eye blinks within 0.25 seconds after exposure. A laser beam generally possesses much higher intensity and can therefore damage the retina before the blink reflex is activated.
The protection has to be initiated very quickly due to the extremely
sharp rise time of pulsed lasers.
The only materials that now can be envisaged and
which are able to combine high
transmission, instantaneous activation and broadband optical protection
are so-called self-activating materials. Such materials should
ideally change their optical properties under the influence of
intense optical radiation, according to
The material should be produced under the boundary conditions of having high transmission at normal, low-, intensities, of being soluble, and of being resistant to optical decomposition. The material should also be ``system compatible'' for the actual production of a device.
The scientific originality of this project refers to new ways of utilizing the non-linear interaction between electro-magnetic fields and matter in order to control light and to design materials with specific optical properties. Among several non-linear processes the network research focuses on the two-photon absorption (TPA), the excited state absorption (ESA), and the reversed saturated absorption (RSA) processes, but other processes or mechanisms is also be considered to obtain a complete picture of the nature of optical power limiting.
In principle we need to control and understand the whole of the so-called
Jablonski diagram give in the picture below:
The project connects closely to the dynamic laser methodology
project. Interested are asked to
contact