A more efficient laser-projection system for high-quality images
Laser light is considered the light source of the future for projectors because it can create high-quality images, requires little maintenance and is increasingly affordable. Nevertheless, heat-sensitive elements in laser projectors today limit the maximum power of the laser, and are a bottleneck for projecting larger, brighter images. Professors in the Department of Applied Physics and the UB Institute of Nanoscience and Nanotechnology Estela Martín and Mario Montes, with predoc researcher Dorian Treptow, have developed a new laser-projection system that, thanks to holographic modulation, can handle much higher optical powers, surpassing currently available systems in size and brightness of the images it creates.
Lasers provide an unprecedented range of colours, brightness and contrast, which means they can project images of extraordinary quality. One of the properties of this light is called coherence, which modulates the wavefronts using holographic techniques and gives better contrast and luminous efficacy. The drawback to holographic modulation, however, is that it creates a pattern that looks like blurry dots called a holographic speckle pattern, which reduces the quality of the image.
Current solutions to limit this speckling are effective but also negatively impact performance of laser projectors in terms of quality, brightness and size of the images. The technology developed at the UB reduces the speckling using acousto-optic deflectors, which shape the light using sound waves and are often used in applications that require a lot of power, such as processing materials with laser and confocal microscopes. The new system, which has been tested in the lab, takes advantage of the propagation of the sound wave in these deflectors to eliminate speckling, and because it can work with high optical powers it can be used to achieve high-quality, large and intense projections.
Bosch i Gimpera Foundation, the knowledge and technology transfer office of the UB, has granted this project €25,000 through the Fund for the Promotion of Innovation (F2I) programme, which will allow them to develop a prototype that can project a full-colour video in a lab setting.