By Futurist Thomas Frey
Researchers at the University of Maryland’s Joint Quantum Institute just solved one of photonics’ most frustrating problems: they’ve designed and tested new chips that reliably convert one color of light into a trio of hues, and remarkably, the chips all work without any active inputs or painstaking optimization.
This might sound like an incremental improvement—better lasers, more colors, so what? But it’s actually revolutionary. These chips take a single invisible telecom laser and passively transform it into red, green, and blue light automatically, with no tuning, no adjustment, and no delicate calibration. And that changes everything about how we build quantum computers, ultra-precise atomic clocks, optical communication systems, and photonic processors.
Why This Is Hard
Designing a photonic chip requires balancing several things in order to generate an effect like frequency doubling. First, to double the frequency of light, a nonlinear resonator must support both the original frequency and the doubled frequency. Just as a plucked guitar string will only hum with certain tones, an optical resonator only hosts photons with certain frequencies, determined by its size and shape.
But that’s just the beginning. Once you design a resonator with those frequencies locked in, you must also ensure that they circulate around the resonator at the same speed. If not, they will fall out of sync with each other, and the efficiency of the conversion will suffer.
These requirements—called frequency-phase matching conditions—are notoriously finicky. Tiny fabrication errors of just a few nanometers can destroy the delicate conditions needed for efficient conversion. Previously, researchers would fabricate dozens of chips and hope a few worked. Most didn’t. The hit-or-miss nature made photonic devices impractical for commercial deployment.
What Makes This Breakthrough Different
The Maryland team’s innovation is making these chips work reliably without active control. The team’s chip can take telecom laser light at about 190 THz (standard in fiber networks) and convert it into its 2nd, 3rd, and 4th harmonics, which, for their setup, correspond to red, green, and blue light.
You put invisible infrared light in. You get visible RGB light out. Automatically. Every time. Without adjustment.
The technical achievement is that all the chips work, not just a lucky few. They’ve solved the reproducibility problem that has plagued nonlinear photonics for decades. The team described their results in the journal Science on November 6, 2025.
Why Multiple Colors Matter
Modern technology depends on lasers at specific wavelengths for different purposes. Quantum computers need particular frequencies to control atoms and ions. Atomic clocks require ultra-stable light at precise colors. Optical communication uses specific wavelengths for transmitting data.
Traditionally, each application required its own dedicated laser—expensive, bulky, power-hungry. You’d need a lab full of different laser systems, each carefully maintained and aligned. Instead of building a zoo of dedicated lasers, a single chip-based frequency converter could feed multiple quantum systems at once.
This matters practically because: Being able to convert that one “workhorse” laser into multiple useful colors on-chip could simplify optical hardware and reduce energy use in telecommunications and data centers where laser systems currently consume enormous power.
The Applications Transforming by 2040
Quantum computing: Quantum systems based on trapped ions and neutral atoms require laser light at very specific wavelengths to manipulate qubits. Currently, quantum computers are surrounded by rooms full of laser equipment. These chips could shrink that infrastructure dramatically, making quantum computers more practical and portable.
Atomic clocks: The most precise timekeeping devices on Earth use frequency combs—lasers that produce multiple colors simultaneously. A compact chip that passively generates multiple stable frequencies is a major win for making atomic clocks smaller and deployable outside laboratories.
Optical communications: Data centers and telecommunications networks rely on wavelength division multiplexing—sending multiple data streams simultaneously on different colors of light through the same fiber. Chips that can generate multiple stable wavelengths from one laser simplify network architecture and reduce costs.
Photonic computing: Future computers might process information using light instead of electricity. Nonlinear effects are the backbone of many advanced photonic computing schemes. Making these effects robust and reproducible opens the door to more practical photonic processors.
Medical imaging and sensing: Biological sensing and medical diagnostics often require multiple laser wavelengths to probe different tissues or molecules. Compact multi-wavelength sources enable portable diagnostic devices.
The Bigger Transformation
This breakthrough is part of a larger shift toward photonic integration—putting optical functions that currently require room-sized equipment onto chips the size of your fingernail.
We’ve already seen this transformation in electronics. The computers that once filled entire rooms now fit in your pocket. Photonics is undergoing the same compression, and reliable frequency conversion is a crucial enabling technology.
By 2040, the laser systems that currently occupy entire optical tables in research labs will be single chips. Quantum computers will be desktop-sized rather than room-sized. Atomic clocks will be portable rather than fixed installations. Optical communication systems will integrate dozens of functions onto chips no larger than current microprocessors.
What Still Needs Solving
While this breakthrough is significant, challenges remain. The chips work passively, but they still require a high-quality input laser. Efficiency—how much of the input light converts to desired colors—continues improving but isn’t perfect yet. Manufacturing at commercial scale while maintaining the precise tolerances required will take years to optimize.
Integration with other photonic components—modulators, detectors, switches—onto single chips requires solving additional materials science and fabrication challenges. And making these systems affordable enough for widespread deployment will require driving costs down through volume manufacturing.
But the fundamental barrier—reliable, reproducible frequency conversion without active control—has been overcome. Everything else is engineering refinement.
Final Thoughts
A chip that passively turns one laser into multiple colors might not sound like world-changing technology. But it removes a fundamental bottleneck that has constrained photonics for decades.
By making frequency conversion reliable and reproducible, these chips enable applications that were previously impractical. Quantum computers become portable. Atomic clocks become deployable. Optical networks become simpler and more efficient. Photonic processors become viable.
By 2040, the rainbow chips developed at Maryland will seem as fundamental to photonics as transistors are to electronics—the basic building block that makes everything else possible. And we’ll look back and recognize this as the moment when photonics stopped being laboratory curiosity and became practical infrastructure.
One laser goes in. Multiple colors come out. Automatically. And everything built on light becomes smaller, cheaper, and more capable.
Related Stories:
https://phys.org/news/2025-11-photonic-chips-passively-laser-multiple.html
https://www.science.org/doi/10.1126/science.adu6368
