Photonics: MIT researchers develop chip-based 3D printer

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A team from the Massachusetts Institute of Technology (MIT) and the University of Texas at Austin has developed a proof of concept for a 3D printer based on a single photonic chip. They have now published the concept as open access in the journal "Nature Light Science and Applications".

The concept does not require any moving parts and could pave the way for compact, mobile 3D printers. The approach combines silicon photonics and photochemistry: the millimeter-sized chip emits reconfigurable light beams into a resin pool. The resin hardens as soon as it is hit by light of a certain wavelength. Instead of moving parts, the chip controls the light beam via an array of tiny optical antennas. Two-dimensional shapes such as letters can be printed in a matter of seconds.

"This system completely redefines the 3D printer. It's no longer a big box that sits on a workbench in the lab and creates objects, but something portable that fits in your hand," says Jelena Notaros, lead author of the study and Professor of Electrical Engineering and Computer Science at MIT.

Light beam determines the shape of the object

The prototype consists of a single photonic chip containing an array of optical antennas with a thickness of 160 nanometers. The entire chip fits on an American quarter dollar coin – comparable to a European 50-cent coin.

When the chip is irradiated with an external laser, the antennas emit a controllable beam of light into the resin pool. The chip is located under a transparent slide of the type used in microscopes. This contains a shallow recess in which the resin is located. The researchers use electrical signals to control the light beam non-mechanically. Where the beam hits, the resin hardens.

The researchers use liquid crystals to modulate the visible wavelength of the light. Their optical properties make it possible to precisely control the amplitude and phase of the light directed to the antennas.

Curing with visible light thanks to special resin

A team led by Zachariah Page from the University of Texas at Austin developed special resins in parallel that can be cured quickly using visible light wavelengths. Until now, it has been difficult to cure photo-curing resins with infrared wavelengths, which integrated optical phased array systems have used in the past for lidar applications.

In the long term, the researchers envision a system in which a photonic chip sits at the bottom of a resin tank and emits a 3D hologram of visible light that rapidly cures an entire object in a single step.

Vision: 3D hologram made of visible light

Such mobile 3D printers could be used to produce customized medical products, for example, or to enable engineers to carry out rapid prototyping on site. According to the researchers, a new design for silicon photonic chips is required to achieve this. The study already outlines what such a system could look like.

(vza)