tech

This work combines the fields of silicon photonics and photochemistry to propose the first chip-based 3D printing technology.

Imagine being able to create 3D objects in the palm of your hand within seconds.

Although 3D printing has revolutionized the way almost every aspect of modern society is created, current 3D printers rely on large and complex mechanical systems for layer-by-layer material addition. This limits the printing speed, resolution, portability, form factor, and material complexity. Despite recent efforts to develop new types of 3D printers based on photopolymerization, which use light to transform matter from liquid resin into solid objects through advanced methods, they still depend on bulky and complex mechanical systems.

To address these limitations, researchers from MIT and the University of Texas at Austin have combined the fields of silicon photonics and photochemistry to propose the first chip-based 3D printer. The proposed system consists of a single millimeter-scale photonic chip with no moving parts, capable of projecting reconfigurable visible light holograms into a simple fixed resin well to achieve non-mechanical 3D printing.

Researchers from MIT and the University of Texas at Austin have demonstrated the first chip-based 3D printer, taking an important step towards realizing this idea. Their proof-of-concept device consists of a millimeter-scale photonic chip that emits reconfigurable beams into a resin well, which solidifies into a solid shape when exposed to the beam's wavelength of visible light.

Advertisement

The prototype chip has no moving parts and instead relies on an array of micro optical antennae to control the beams. The beams are projected upwards into the liquid resin, which cures rapidly when exposed to the visible light wavelength of the beams.By integrating silicon photonics and photochemistry, this interdisciplinary research team has successfully developed a chip that can guide a laser beam to 3D print any two-dimensional pattern, including letters, in just a few seconds, with the shape fully formed.

In the long term, they envision a system where the photonic chip is placed at the bottom of a resin well and emits a visible light 3D holographic image, quickly curing the entire object in one step.

This portable 3D printer has many applications, such as allowing clinicians to create custom medical device components or enabling engineers to produce rapid prototypes on-site.

"The system completely redefines the 3D printer. It is no longer a large box placed on a laboratory bench to manufacture objects, but something that can be handheld and carried. It's exciting to think about the new applications that may arise and how the field of 3D printing will change," said author Jelena Notaros, who is the Robert J. Shillman Career Development Professor in Electrical Engineering and Computer Science (EECS) and a member of the Electronics Research Laboratory.

Joining Notaros in writing the paper are first author Sabrina Corsetti, an EECS graduate student, Dr. Milica Notaros (class of '23), EECS graduate student Tal Sneh, recent University of Texas at Austin graduate Alex Safford, and Assistant Professor Zak Page from the Department of Chemical Engineering at the University of Texas at Austin. The research was published today (June 6) in Light: Science & Applications.

Using the chip for printing

Notaros' team is an expert in silicon photonics. They previously developed an integrated optical phased array system that uses a series of micro-antennas manufactured on the chip using semiconductor manufacturing processes to control the laser beam. By accelerating or delaying the light signals on both sides of the antenna array, they can deflect the emitted beam in a certain direction.

Such systems are key to LIDAR sensors, which emit infrared beams that reflect off nearby objects, mapping the surrounding environment. Recently, the team has focused on systems for emitting and guiding visible light for augmented reality applications.

They wondered if this device could be used for a chip-based 3D printer.As they began to brainstorm collectively, the Page Group from the University of Texas at Austin first demonstrated a dedicated resin that could be rapidly cured using visible light wavelengths. This was the missing piece that propelled the reality of chip-based 3D printers.

"For photopolymerizable resins, it is difficult to fully cure them at infrared wavelengths, and in the past, integrated optical phased array systems have worked for LiDAR at infrared wavelengths," said Coletti. "Here, we have found a balance between standard photopolymerization and silicon photonics by using visible light curable resins and visible light emitting chips, creating this chip-based 3D printer. You merge these two technologies into a completely new idea."

Their prototype consists of a photonic chip, which includes a set of optical antennas with a thickness of 160 nanometers. (The thickness of a sheet of paper is about 100,000 nanometers.) The entire chip can fit on a 25-cent coin.

When powered by a laser outside the chip, the antennas emit a controllable beam of visible light into the photopolymerizable resin tank. The chip is located under a transparent glass slide, similar to the slides used in microscopes, and the slide has a shallow recess to hold the resin. Researchers use electrical signals to non-mechanically manipulate the beam, causing the resin to cure where the beam is exposed.

Discussion Points

This work combines the fields of silicon photonics and photochemistry, proposing the first chip-based 3D printing technology. The proposed system consists of a single millimeter-scale photonic chip with no moving parts, capable of emitting reconfigurable visible light holograms into a simple fixed resin well, enabling non-mechanical 3D printing.

Firstly, the team proposed the concept of this chip-based universal 3D printer and outlined the key requirements for full implementation.

Secondly, as a proof-of-concept demonstration, a stereolithographic version of this chip-based 3D printer concept was experimentally demonstrated by combining emerging technologies such as visible light integrated optical phased arrays and visible light-activated photochemistry; the system consists of a visible light integrated optical phased array that can emit beams and non-mechanically guide them into visible light curable resin wells.

Thirdly, the system was used to photo-cure voxels, demonstrating for the first time the use of a chip-based system for 3D printing.Fourth, the curing rate of the system is characterized by measuring the relationship between the size and curing time of individual 3D printed voxels, and it is observed that sub-millimeter voxels are printed out in a few seconds.

Fifth, the non-mechanical beam guidance function of the system is utilized to achieve 3D printing of one-dimensional lines without any moving parts.

Finally, this function is extended to demonstrate 3D printing of arbitrary patterns in two dimensions using the system.

In the future, the team will expand the preliminary proof-of-concept demonstration proposed in this paper and showcase a complete chip-based volumetric 3D printing concept. As an initial step in utilizing the current chip-based 3D printer, an off-chip tunable visible wavelength laser will be coupled on the chip, capable of performing non-mechanical wavelength beam control on the antenna dimensions of the integrated optical phased array 66.

The chip-based 3D printing technology introduced in this study is expected to provide a highly compact, portable, and low-cost solution for the next generation of 3D printers. This solution will offer a more convenient and faster mechanism for generating 3D objects, impacting a wide range of applications in military, medical, engineering, and consumer fields.