The main objective of this project is the development of a number of the most promising smart micro-opto-electro-mechanical components using IC-compatible micro-machining technology. The project will make the technology available to industrial and university users in the EU in order to assess the different possibilities of silicon based micro-optics, early and in the long run, strengthen the position of the European optical industry in the world market.
Present-day optical equipment makes heavy demands on the geometry of optical components. The surfaces of mirrors and lenses must match the design tolerances with sub-micron precision. Moreover, very high demands are put on the relative positioning of the optical components. Traditionally, to fulfil these requirements, optical systems are characterised by a very rigid design based on fixed components.
Progress in informatics and electronics has created new applications for optical systems. However, such systems must be able to adapt themselves to changing environments. This ability is in conflict with the requirement that optical systems should have a solid geometry. Optical components as required by new information processing and transmission systems must be rigid and flexible at the same time!
When available, tuneable and adaptive optical components and systems can be applied in many traditional and new fields:
- In modern applied optics, including astronomical optics, optical information, and (robot) vision systems. Active and adaptive optics in astronomy can dramatically increase the resolution of the ground-based telescopes. Adaptive optical components are required for information and vision systems, but are not widely used yet, mainly due to the high costs of present-day adaptive optical components and control systems.
- In optical information processing and display technology, including:
-optical computing and optical neural networks,
-spatial light modulators and fast optical modulators for information systems
-optical (projection) display devices.
- Adaptive optics are currently used in the laser industry for improving the quality of the laser beam. Adaptive optics increase the quality and stability of industrial lasers and allow for new processing regimes.
Up to now various technologies have been tried for the fabrication of tuneable optical components. One example of such a system is an adaptive mirror, used for the correction of the beam quality in astronomy and laser optics. It is a very expensive opto-electro-mechanical device. The cost of the technology is very high because optical, mechanical and electronics technologies had to be combined in one device. Devices now on the market in the USA have prices higher than $1000 per control channel, while one adaptive mirror may include from tens to hundreds of such channels.
In the field of sensors, actuators and microsystems many new processing steps have been invented and applied to rather complex silicon structures. We now strongly believe that the introduction of the relatively inexpensive and uniform micro-fabrication technology to the field of adaptive optics will create a breakthrough in optical information processing, mainly because of the reduction in the fabrication costs, the improvement of device performances, and especially because of the electronic control of the optical parameters.
To better understand the potential of micro machining of silicon in the field of optics, IC processing technology has been successfully applied to the fabrication of a number of adaptive optical components in the Electronic Instrumentation Laboratory of the Delft University of Technology in co-operation with the Delft Institute of Microelectronics and Sub micron Technology (DIMES). Adaptive mirrors with 9 and 16 control channels, tuneable interferometer arrays, and demonstrators of spatial light modulators among others were fabricated and characterised. Preliminary experiments show that the technology is very well suited for the fabrication of spatial light modulators, displays and other micro-opto-electro-mechanical devices. It appears that silicon is not only a good semiconductor and an excellent mechanical material, but is also very suitable for the fabrication of electrically controlled micro optical components. Silicon-based micro optics might lead to a new generation of relatively low-cost optical components with the important advantage that they can be electronically controlled and adjusted