The application of 3D holograms is far-reaching, especially in the field of medical technology. The real-time and dynamic hologram is predicted to shorten the operation time and provide better operation effect. Dynamic three-dimensional hologram is likely to replace the current two-dimensional imaging, such as magnetic resonance scanning, so that surgeons can have a more comprehensive real-time understanding of the internal system of patients, thus reducing the invasive nature of surgery and reducing accidents on the operating table.
The wide use of 3D holograms requires a new type of miniaturized optical system, which can be integrated on the chip with minimum power consumption, can move the beam to free space, control the beam shape, and have tunable wavefront. Although existing technologies can answer these questions, so far, it is difficult to combine them into a single system.
TMOS is the center of excellence for hypersurface optical systems of the Australian Research Council. The researchers of the center use hypersurface optics to combine vertical nanowires with micro-ring lasers made of semiconductor nanostructures, making this technology a step towards reality.
Vertical nanowires have special directionality and can effectively form laser beams, but their configuration will cause significant photon leakage in the laser process. The place where the photon reflecting base mirror is also where the nanowire is connected with the substrate. This connection makes the nanowire become an inefficient laser.
On the other hand, in micro-ring lasers, most of the photons move in parallel with the substrate, thus reducing photon leakage and achieving higher laser efficiency, but it is very difficult to control the direction and shape of the beam.
For the first time in the world, researchers of TMOS combined InP micro-ring laser cavity with vertical InP nanowire antenna. The antenna is located in the center of the cavity, guiding photons to a free space with a specific beam shape, which is the development required for 3D holograms. The micro-ring and nanowire cavity are used as light source and antenna respectively, and the selective area epitaxy technology is used to grow simultaneously.
The size of this equipment is less than 5 μ m. Finally, a single hologram pixel can be formed. The effectiveness of this coupling has been proved in the laboratory, and the details are published in the journal Laser and Photonics Review.
Wei Wen Wong, the lead author of the study, said: “This is the way forward for the on-chip micro-laser with low power consumption and tunable emission. This new development has removed a key obstacle to the realization of 3D holograms. We hope that this novel device can one day be integrated into a device that is small enough and cheap enough, so that medical professionals can put it into their pockets when going to remote areas, so that they can project full-color dynamic holograms from the on-site operating table.”
Hoe Tan, chief researcher of TMOS, said: “The development of dynamic holograms is one of the flagship projects of our center. Teams from five participating universities are working together to make this goal a reality. The next step of our research is to create a pixel array, in which the wavefront and beam shape can be independently controlled and dynamically adjusted.”