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| Researcher Jeongho Ha (center) is part of a team that developed the first photonic devices that are both highly sensitive and robust. Courtesy of University of California, San Diego Jacobs School of Engineering/David Baillot. | Image Source: Photonics Spectra |
📍 SAN DIEGO, Calif., July 7, 2025 — In a major advancement for integrated photonics, researchers at the University of California, San Diego have developed a new class of chip-scale photonic devices that overcome a long-standing trade-off between sensitivity and robustness. This innovation could pave the way for more powerful, precise, and scalable technologies in fields ranging from medical diagnostics to secure communications.
Photonic devices, which
manipulate light to perform sensing, communication, and computational tasks,
have traditionally faced a fundamental limitation: the more sensitive a device
is to its environment, the more vulnerable it becomes to fabrication imperfections
and external disturbances. Conversely, increasing a device’s durability often
comes at the cost of reduced sensitivity. This contradiction, rooted in the
physics of wave dynamics, has hindered the development of reliable,
high-performance photonic systems.
Now, a team led by Professor
Abdoulaye Ndao has resolved this paradox by leveraging a phenomenon known as subwavelength
phase singularity within a chiral medium. “Our
research addresses this critical challenge,” said Ndao. “We have designed new
photonic devices that are both highly sensitive to their environment and robust
against fabrication errors and material imperfections.” (“Sensitive Yet
Tough Photonic Devices Are Now a Reality”)
A Precision-Engineered
Photonic Platform
The team’s innovation centers on
a compact, chip-scale device constructed from two layers of gold nanorods,
separated by an ultra-thin polymer film. The bottom layer is embedded within
the polymer. In contrast, the top layer is exposed to air, allowing it to
directly interact with target molecules — a crucial feature for sensing
applications, particularly in detecting chiral analytes.
The nanorods in each layer are
arranged in parallel rows, twisted at specific angles relative to one another.
By precisely adjusting the horizontal spacing and angular alignment between the
layers, the researchers were able to finely tune the device’s interaction with
circularly polarized light — both right-handed and left-handed — as it passes
through the structure.
This configuration enables the
formation of subwavelength phase singularities, where light is confined
to a space smaller than its wavelength. At these singularities, the intensity
of light drops to zero, creating a point of complete darkness, while the phase
of the light continues to evolve. This unique optical behavior makes the device
extraordinarily sensitive to even the slightest environmental changes.
Sensitivity Meets Stability
What makes this breakthrough
particularly compelling is the device’s resilience to imperfections introduced
during the manufacturing process. Traditional high-sensitivity photonic devices
are often fragile and prone to failure due to minor structural deviations. In
contrast, the UC San Diego device maintains its performance even in the
presence of such imperfections, offering a rare combination of precision and
durability.
The researchers validated the
device’s performance through experimental measurements of its phase
singularities, confirming both its high sensitivity and structural robustness.
This dual capability opens the door to a wide range of practical applications,
including biosensing, environmental monitoring, optical
imaging, and quantum communications, all within a compact and
scalable platform.
A Path Toward Scalable
Photonic Systems
The use of phase singularities
not only enhances sensitivity but also relaxes the stringent fabrication
tolerances that typically constrain photonic device design. This flexibility
could significantly reduce production costs and accelerate the deployment of
advanced photonic technologies across various industries.
“Phase
singularity makes the light extremely sensitive to external changes, which is
useful for high-precision detectors, optical communications, and imaging,” Ndao
explained. “This is the first device that is both sensitive and robust to
fabrication imperfections. (“Photonic Devices Deliver Power and Precision
to Next-Gen On-Chip ...”)
We have developed tiny optical
devices that are both tough and extremely sensitive at the same time — a
combination that was previously thought to be impossible.” (“Sensitive yet
tough photonic devices are now a reality”)
Looking Ahead
As the demand for miniaturized,
high-performance optical components continues to grow, this innovation
represents a critical step forward. By bridging the gap between sensitivity and
stability, the UC San Diego team has laid the foundation for a new generation
of photonic devices that are not only more powerful and precise but also
practical for real-world deployment.
References:
“Photonic
Devices Deliver Power and Precision to Next-Gen On-Chip Sensors.” Photonics
Spectra, 7 July 2025, www.photonics.com/Articles/Photonic_Devices_Deliver_Power_and_Precision_to/a71190