The application of 3D hologram is far-reaching, especially in the field of medical technology. Real time and dynamic holograms are predicted to shorten the operation time and provide better surgical results. Dynamic three-dimensional holograms may replace the current two-dimensional imaging, such as MRI scanning, so that surgeons can have a more comprehensive real-time understanding of the patient's internal system, thus reducing the invasion of surgery and the accidents on the operating table.
The widespread use of 3D holograms requires a new type of miniaturized optical system, which can be integrated on a chip with minimum power consumption, can move the beam to free space, control the beam shape, and have a tunable wavefront. Although existing technologies can answer these questions, it is difficult to combine them into a single system so far.
TMOS is an excellent hypersurface optical system center of the Australian Research Council. Its researchers use hypersurface optics to combine vertical nanowires with microring lasers made of semiconductor nanostructures, making this technology a step closer to reality.
Vertical nanowires have special directivity and can effectively form laser beams, but their configuration will lead to significant photon leakage in the laser process. The place of the photon reflecting base mirror is also the place where the nanowires connect with the substrate, which makes the nanowires become inefficient lasers.
On the other hand, in a micro ring laser, most photons move parallel to the substrate, which reduces photon leakage and enables higher laser efficiency. However, 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 and guides photons to free space with specific beam shape, which is a development required for 3D hologram. Microring and nanowire cavity are used as light source and antenna respectively, and are grown simultaneously by selective area epitaxy.
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 to move towards the low-power, tunable emission direction of on-chip micro lasers. This new development eliminates 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 to allow medical professionals to pocket when going to remote areas, so that full color dynamic holograms can be projected from the on-site operating table."
Hoe Tan, the 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, where the wavefront and beam shape can be independently controlled and dynamically adjusted."
Source: OFweek
