Lichtgedanken 04

S C HW E R P U N K T 25 04 | LICHT GEDANKEN in the air. The intensity is so great that it ionizes the air molecules and thus disrupts them. Electrons and ions sep- arate resulting in a plasma. But, as soon as the electrons return and recombine, they emit visible light. Scanner techno- logy—i.e. moving mirrors—can then be used to move this light point. If you do this at high speed, the result is three-di- mensional structures appearing in the air. Computer data defines how these structures look. »To put it simply, we light up the air so we can then draw with it«, says Roland Ackermann. In addition to air, the Jena scientists have also experimented with various other gases to find out whether they can produce brighter lines. The noble gas ar- gon would be better suited. »But air has a big advantage over the rest: you don't need to create a special environment for it«, says Kammel. The physicists have spent the last three years preparing the foundations for the new method. Now the challenge is to develop the technology so it is ready for use. The 3D images that have been pro- duced up to this point are very small. The cube made up of illuminated lines has an edge length of just five milli- metres, for example. This is something the researchers want to change with the recently commenced follow-up project »EiM3D—eigen-haptische Manipula- tion ausgedehnter 3D-Strukturen im Raum« (EiM3D—separate haptic ma- nipulation of extended 3D structures in free space). They want to use an adap­ tive mirror with a reformable surface— developed by the Fraunhofer Institute for Applied Optics and Precision Engin- eering—for this purpose; it will help to deflect the light points downwards at extreme speed. To date, lenses have had to be moved mechanically, which limits the size of the structures that can be dis- played and thwarts the picture genera- tion. 3D images to be moved freely in the air using gestures Furthermore, the researchers will spend the next months focusing on an additional function, which goes beyond pure image reproduction: »To- gether with the Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute in Berlin, we are currently de- veloping a control that will allow us to move the 3D images using gestures«, explains Roland Ackermann. »A cam- era system records hand movements, forwards this information to the com- puter, which then uses it to alter the 3D structure. The result is an interactive imaging system.« Thus, it is possible to move the cube with great sensitivity by moving your hand towards it, without touching the image. Applications, like in an architecture firm, could become the reality. »It will take us at least another five to ten years to get to the point where com- pact systems offering this technology are found in offices or used in prac- tice«, estimates Robert Kammel. »In order to reach this point, we need to make the system far more efficient and lower the requirements on the laser, for example.« But, we are already at a point where this is far from »fiction«. Contact Prof. Dr Stefan Nolte Institute of Applied Physics Albert‐Einstein‐Straße 15, D-07745 Jena, Germany Phone: +49 36 41 9-47 820 Email: stefan.nolte@uni-jena.de www.iap.uni-jena.de Further Information: www.3d-sensation.de www.iap.uni-jena.de/Ultrafast+Optics.html C Image left: The three-dimensional presentation of complex objects in free space remains a vision of the future; but the technical foundations are already in place. Image right: The method, which physicists at the Institute of Applied Physics and colleagues from the Fraunhofer Institute for Applied Optics and Precision Engineering are working on, already works very well for small objects, such as this cube with an edge length of around half a centimetre. The Jena-based research projects are being funded by the state. F E AT U R E