Developing 3D live hologram technology to save lives in field hospitals

3D holograms from your phone, television, or favorite droid have been promised for decades, but despite great interest, have yet to materialize. Applications for them are far-reaching, especially in the field of medtech where real-time, dynamic holograms are predicted to reduce operating time and provide better surgical outcomes.

Dynamic 3D holograms have the potential to replace current 2D imaging such as MRI scans, giving surgeons a more comprehensive understanding of a patient’s internal systems in real time, leading to more efficient surgeries and fewer surprises on the operating table.

Although the impact of 3D holograms in medicine has been known for some time, researchers have faced roadblocks in developing the technology without resorting to bulky, non-portable, and expensive systems that can only be used in large, established hospitals. A major barrier to widespread adoption.

A new, miniaturized optical system is needed, one that can be integrated on a chip, has low power consumption, can move a beam to free space, can control the beam shape, and has a tunable wavefront.

While the technology exists to answer each of these points, integrating them into a single system has so far been elusive.

Researchers at TMOS, the Australian Research Council Center of Excellence for Transformative Meta-Optical Systems, have taken this technology a step closer to reality with meta-optics, a combination of vertical nanowires and microring lasers made from semiconductor nanostructures.

Vertical nanowires have exceptional directivity and can effectively shape the laser beam, although their configuration causes significant photon leakage during the lasing process. The nanowire bonds to a substrate where photons reflect off the underlying mirror, and that bond makes the nanowire an inefficient laser.

In a microring laser, on the other hand, most of the photons in a microring laser travel parallel to the substrate, resulting in photon leakage and very high lasing efficiency, although controlling the direction and shape of the beam is incredibly difficult.

In a world first, TMOS researchers have combined an InP microring laser cavity with a vertical InP nanowire antenna sitting at its center to direct photons into freespace with specific beam shapes, a development required for 3D holograms. The microring and nanowire cavities, which act as the light source and antenna in the system, respectively, are grown simultaneously using a selective area epitaxy technique.

The device is less than 5 microns in size and can eventually form a single hologram pixel. The effectiveness of this coupling has been demonstrated in the lab and the details published Lasers & Photonics Review today

Lead author Wei Wen Wong says, “This is a path to low power consumption, on-chip microlasers with tunable emission directionality. This new development removes one of the major barriers to realizing 3D holograms.”

Our hope is that this novel device will one day be integrated into a device small enough to slip into the pocket of medical professionals when traveling to remote areas, allowing full-color dynamic holograms to be projected from field operating tables.”

TMOS Chief Investigator Ho Tan says, “The development of dynamic holograms is one of the core projects of our center. Teams from the five participating universities are working together to make this a reality. The next steps in our research are to create an array of pixels. The wavefront and beam shape can be adjusted individually and dynamically.”