Photonics: Programmable PIC; small optical features in hydrogels; on-chip UV generation.
Researchers from the University of Washington designed a low-power programmable photonic integrated circuit that is electrically reconfigurable and can be mass-produced.
“This optical chip could help to accelerate the prototyping cycle while reducing power consumption for applications like AI computing. Our study is also the first time someone has shown that these kinds of optical circuits can be controlled with electrical signals, reliably and very accurately,” said Rui Chen, postdoctoral research associate at MIT and former doctoral student at UW, in a press release. “We built our circuit using common foundry processes, which demonstrates the scalability of the system.”
To reduce power consumption, the device uses phase-change materials that enable it to maintain its programmed or reconfigured state without a power supply.
Next, the team plans to build a larger-scale optoelectronic system containing the optical chip. “An important next step is to test this optical chip in some real applications,” Chen added. “We’d like to put this circuit in application scenarios, such as AI computing, optical switches in data center infrastructure, and optical sensing.” [1]
Researchers from Massachusetts Institute of Technology (MIT) used a fabrication technique called implosion carving to create optical computing devices. The technique imprints 3D features throughout a hydrogel. The hydrogel is immersed in a photosensitizing dye, and a laser is used to create vacancies in the desired pattern. The hydrogel is then shrunk in a two-step process, reducing 800nm feature sizes to 100nm.
“In order to enable nanophotonic applications in visible light, we need to make nanostructures with feature sizes with a resolution less than 100 nanometers. Only in that way can we precisely create the structure that can manipulate visible light,” said Quansan Yang, assistant professor at the University of Washington and former MIT postdoc, in a press release.
The demonstration device was capable of performing a simple digit-classification task using a pattern of vacancies that diffracts input light as it passes through layers of patterned hydrogel, so that the output light was determined by the shape of the digit that was entered into the system. While the demonstration showed a simple neural network task, the team plans to use the same principles for high-throughput imaging techniques, such as optical devices that classify cells based on their state as they flow through a microfluidic device.
“One of the very attractive features of this technology is that you can manipulate the property of the material at every tiny location,” said Dushan Wadduwage, an assistant professor at Old Dominion University and former MIT postdoc, in a press release. “You have millions of different locations that you need to decide the property of, and that turns into a really interesting design problem where we can use deep-learning algorithms to find designs over these millions of parameters and come up with parts that go into optical systems in new ways.” [2]
Researchers from Harvard University and the University of Twente were able to generate milliwatt-level UV light on a thin-film lithium niobate (TFLN) photonic chip. To produce the UV light, the team generated two red light photons before converting them to a single UV photon.
The team built a waveguide on the TFLN platform with electrodes brought up against the sidewalls to reverse the orientation of the material’s crystal structure periodically, up to a thousand times per millimeter. The alternating voltage on and off along the waveguide created the pattern that enables conversion.
In previous versions, the electrodes were placed further from the waveguide. “In our design, they sit right on it,” said Kees Franken, postdoc at UT and CEO of spin-off Sabratha, which is commercializing TFLN technology, in a statement. “That required a fabrication process accurate to fifty nanometers across a chip several centimeters long. But it gives us far more control, and the conversion from red to UV works much more efficiently.”
Potential applications include quantum technology, optical atomic clocks, and measurement equipment. [3]
[1] R. Chen, A. Tang, J. Dutta, et al. NEO-PGA: Nonvolatile electro-optically programmable gate array. Sci. Adv. 12, eaea9383 (2026). https://doi.org/10.1126/sciadv.aea9383
[2] Q. Yang, G. Yang, T. Nambara, et al. Isotropic shrinkage of patterned vacancies enables three-dimensional nanoprecise metastructures for visible light applications. Nat. Photon. (2026). https://doi.org/10.1038/s41566-026-01896-1
[3] C.A.A. Franken, S.S. Ghosh, C.C. Rodrigues, et al. Milliwatt-level UV generation using sidewall poled lithium niobate. Nat Commun 17, 3651 (2026). https://doi.org/10.1038/s41467-026-68524-y
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