Optical filters are essential wherever light must be separated, selected or reshaped according to wavelength or frequency. In a telecommunications link, for example, many independent data channels may travel through the same optical fiber, each occupying a narrow spectral band. A filter can isolate one channel, suppress interference from neighboring channels or modify the phase and amplitude of a signal before it is detected. Conventional filters are often designed for a specific task and manufactured with a fixed response. While they can be highly efficient, changing their behavior may require replacing the device or using several separate components. Programmable photonic filters aim to place that control inside the circuit itself.

The system investigated by Valdez, Kroo, Vlk and their colleagues is based on a feed-forward photonic mesh, a network of optical pathways arranged so that light encounters a sequence of tunable interferometric elements. These elements can split an incoming optical field into different paths, adjust the relative phase between those paths and then recombine the signals. Because the different routes introduce controlled delays, the recombined light can interfere constructively at some frequencies and destructively at others. The result is a frequency-dependent transfer function: certain portions of the spectrum pass through, while others are attenuated or redirected.

The operating principle resembles a programmable finite-impulse-response filter, but implemented with photons rather than electronic voltages and currents. In an electronic filter, delayed copies of a signal are multiplied by adjustable coefficients and added together. A photonic mesh performs an optical equivalent of this operation. Each path acts as a possible delayed contribution, while tunable phase shifters and couplers control the weight and phase of the contributions. By changing those settings, the circuit can synthesize different spectral profiles, including narrow transmission windows, rejection bands and more complex responses. The filter is therefore not limited to a single wavelength pattern established at the time of fabrication.

Feed-forward architecture is particularly significant because it differs from designs that send light repeatedly around resonant loops. Resonant structures can produce sharp spectral features, but their performance may depend strongly on loss, thermal stability and precise control of resonance conditions. A feed-forward mesh instead guides light through a defined sequence of interactions. This can make the relationship between the control settings and the resulting response more direct, while also allowing the circuit to be scaled into larger networks of programmable elements. The architecture does not eliminate all practical challenges, but it offers a route toward flexible filtering without requiring light to circulate indefinitely inside the chip.

At the heart of the device are integrated optical components capable of changing the amplitude and phase of light. In many photonic platforms, these functions are provided by Mach–Zehnder interferometers, which combine two optical paths after introducing a controllable phase difference between them. A small adjustment to that phase can shift the balance of power between the output ports. When many such interferometers are connected in a mesh, their collective behavior becomes programmable. The circuit can be configured to realize a desired mathematical transformation, with the optical signal remaining in the photonic domain rather than being converted into an electrical signal at every stage.

That capability could be valuable in systems where speed, bandwidth and energy consumption are tightly constrained. Optical signals can carry enormous amounts of information, and processing them before conversion to electronics may reduce bottlenecks in high-capacity communication links. A programmable filter could be adapted to changing channel allocations, compensate for distortions introduced by a fiber or selectively remove unwanted spectral components. In data centers, similar technology could support agile optical interconnects. In scientific instruments, it could allow a single chip to perform multiple types of spectral analysis. The same principles may also be relevant to lidar, microwave photonics, radio-frequency signal processing and emerging optical computing architectures.

The researchers’ work also highlights an important shift in photonic engineering: from designing individual components to programming networks of components. Rather than fabricating a new filter for every application, engineers could use a common photonic mesh and load different configurations as needed. That approach is analogous to the transition from fixed electronic circuits to programmable digital hardware, although optical systems face distinct challenges involving calibration, fabrication variation, optical loss and the stability of phase settings. To make such devices practical, control electronics must continually maintain the desired operating point while using as little power and space as possible.

The reported concept arrives as researchers worldwide seek ways to make photonic systems more versatile without sacrificing the inherent speed of light-based processing. Feed-forward meshes do not turn optical circuits into universal replacements for electronics, but they provide a powerful platform for reshaping signals with software-like flexibility. If the technology can be integrated at scale and controlled reliably, programmable optical filters could become building blocks for reconfigurable communication networks and compact sensing systems. The broader promise is an optical chip that is not locked into one function: its behavior could be rewritten whenever the application, spectrum or operating environment changes.

Subject of Research: Programmable optical filters based on feed-forward photonic meshes

Article Title: Programmable optical filters based on feed-forward photonic meshes

Article References: Valdez, C.G., Kroo, A.R., Vlk, M. et al. Programmable optical filters based on feed-forward photonic meshes. Light Sci Appl 15, 350 (2026). https://doi.org/10.1038/s41377-026-02461-9

Image Credits: AI Generated

DOI: 10.1038/s41377-026-02461-9

Keywords: photonic filters, programmable photonics, feed-forward photonic meshes, optical communications, integrated photonics, Mach–Zehnder interferometers, spectral processing, optical signal processing

Circularly polarized light is a specialized form of light whose electric field rotates as the wave travels. That rotation can be either left-handed or right-handed, and the distinction is useful because the two states can carry separate channels of information. Conventional technologies often require chiral molecules—molecules whose mirror images cannot be superimposed—to generate or manipulate this type of light. Creating such molecules, however, can involve complicated chemical synthesis, while mixtures of opposite-handed structures can cancel one another’s optical effects.

The KAIST team, led by Professor Dong Ki Yoon of the Department of Chemistry, developed a different strategy based on controlling molecular organization rather than molecular asymmetry. The researchers worked with achiral, rod-shaped liquid-crystal molecules that are individually symmetric. Under carefully controlled conditions, these molecules were confined within microscale spaces and encouraged to assemble into pinwheel-shaped structures. Although the molecules themselves had no inherent handedness, their collective arrangement could adopt either a clockwise or counterclockwise configuration.

The principle resembles the way a flat sheet of paper can be folded into pinwheels that turn in opposite directions. The paper remains the same, but the arrangement of its folds determines the final handedness. In a similar way, the liquid-crystal molecules used in the study were chemically unchanged, while the geometry of their assembly generated a chiral structure. This distinction is important because it separates the origin of the optical response from the chemical identity of the material itself.

The researchers first induced the molecules to self-assemble into microscopic pinwheels. A major challenge was preventing both handednesses from forming at the same time. If clockwise and counterclockwise structures appear in equal or nearly equal numbers, their optical responses can weaken or cancel, making it difficult to produce a strong, uniform signal across a large area. To solve this problem, the team introduced a chiral additive in a concentration of less than 1 percent of the total material. Rather than acting as the primary optical material, the additive served as a molecular guide that selected one pinwheel orientation.

This small amount of chiral material was sufficient to bias the self-assembly process and align the pinwheels with a common handedness. The result was a large-area array of microscale structures with a consistent orientation. The researchers then permanently transferred or replicated the arrangement onto polymer nanofibers, creating a stable chiral platform that could be used as a surface for other optical materials. This replication step is particularly significant because it suggests that the pinwheel architecture can be integrated into flexible or nanoscale devices rather than remaining limited to a temporary liquid-crystal state.

To test whether the structure could control light, the team coated the patterned platform with a conventional luminescent material. When excited, the luminescent coating emitted circularly polarized light. Crucially, the direction of that polarization was determined by the handedness of the underlying pinwheel array rather than by a change in the light-emitting substance. Reversing the orientation of the pinwheels switched the emitted light from one rotational direction to the other, demonstrating that the optical function originated from structural organization.

The finding illustrates a broader design principle in materials science: a material’s properties can emerge from how its building blocks are arranged, even when those building blocks lack the desired property individually. The same idea appears in photonic crystals, metamaterials, liquid-crystal devices, and biological structures, where nanoscale geometry can determine how light, sound, or electrons move. In this case, the pinwheel array creates a chiral optical environment that influences the interaction between the luminescent coating and the emitted electromagnetic field. The structure effectively transfers handedness to light without requiring a fully chiral emitter.

According to the researchers, the platform could help simplify the development of optical technologies that rely on polarization. Displays might use structurally controlled circularly polarized emission to improve light management and reduce optical losses. In augmented- and virtual-reality systems, chiral structures could be incorporated into lightweight polarization-control elements. Optical communication systems could potentially use left- and right-handed polarization states as distinct information channels, while security labels could exploit the ability of a patterned surface to produce a recognizable polarization signature. Polarization sensors may also benefit from materials whose response can be tuned through geometry rather than chemical redesign.

The study was led by first author Jeong Yeon Han, a Ph.D. candidate, in collaboration with scientists from Chungnam National University, Ajou University, Yonsei University, and Japan’s RIKEN. Han explained that conventional methods often produce left- and right-handed structures together, reducing the overall chiral response. By designing the additive concentration and assembly conditions so that one orientation was selected across a broad area, the team overcame that limitation. Professor Yoon said the work demonstrates a new optical-materials principle in which the rotation direction of light is controlled by molecular arrangement rather than by the complex chemical structure of chiral molecules.

Published in Nature Communications, the study presents the pinwheel array as a route to scalable chiral optical materials based on widely available achiral components. The researchers’ next challenge will be to refine the uniformity, efficiency, and manufacturing compatibility of the structures and to determine how they perform in practical devices. If those obstacles can be addressed, microscopic pinwheels made from ordinary molecules could become a powerful way to program the behavior of light—turning molecular architecture into an optical control switch.

Subject of Research: Structural control of circularly polarized light using microscale chiral pinwheel arrays formed from achiral liquid-crystal molecules.

Article Title: Microchiral pinwheel arrays based on achiral molecules

News Publication Date: 14-Aug-2026

Web References: https://doi.org/10.1038/s41467-026-76089-z

References: Han, Jeong Yeon, et al. “Microchiral pinwheel arrays based on achiral molecules.” Nature Communications. DOI: 10.1038/s41467-026-76089-z.

Image Credits: KAIST

Keywords

Circularly polarized light, chirality, achiral molecules, liquid crystals, pinwheel structures, optical materials, nanofibers, photonics, displays, optical communications, polarization sensors, metamaterials, KAIST

Optical beams carrying topological singularities have long fascinated scientists due to their unique properties, wherein tiny regions of zero intensity trace dynamic, knotted trajectories as the light propagates. These phase singularities, often referred to as optical vortices, form complex topological structures analogous to knots and links. Such structures naturally encode vast amounts of information in their spatial and temporal evolution, presenting a promising medium for both classical and quantum communication channels. However, precisely detecting and tracking these singularities has been a stubborn barrier to practical applications, primarily because traditional intensity-based sensors are ill-suited to capture these inherently dark and ephemeral phenomena.

The conventional strategy for detecting optical singularities relies heavily on frame-by-frame intensity imaging, requiring long exposure times to accumulate sufficient signal contrast at the point of darkness. This approach not only produces massive amounts of data, often rich in redundant information, but also imposes a fundamental speed bottleneck due to the slow temporal resolution. Consequently, the transmission rates and responsiveness of such systems have remained constrained, impeding progress toward real-time singularity-based information processing.

The LightELF system ingeniously overcomes these limitations by adopting an event-driven detection paradigm rooted in neuromorphic principles. Rather than conventionally capturing entire frames, LightELF asynchronously detects and outputs singularity positions only when rapid changes in the optical gradient surpass a predefined threshold. This method drastically reduces data redundancy while achieving microsecond-level temporal precision, enabling the system to trace the rapid and intricate topological evolutions of singularities with unprecedented clarity and speed.

A central innovation in LightELF’s methodology is the deployment of logarithmic intensity gradient processing. Since optical singularities naturally manifest as regions with extremely steep intensity gradients, LightELF capitalizes on this by applying logarithmic gradient computation directly at the hardware level. This pre-processing step allows the system to reconstruct topological structures—such as knots and links—without requiring burdensome post-processing algorithms, streamlining the flow from detection to data interpretation and allowing for near-instantaneous signal decoding.

The implications of this technology are profound. By capturing only the essential, information-rich events associated with singularity evolution, LightELF effectively addresses the trilemma of optical data transmission—high temporal resolution, minimized data load, and accurate topological detection. The reduction in data volume without sacrificing the fidelity or speed of information extraction opens new horizons for optical communication systems, optical computing architectures, and neuromorphic photonics.

To demonstrate its capabilities, the researchers implemented a complete data transmission framework using LightELF, encoding image information into optical topological knots and successfully recovering it in real time. For example, they transmitted a 200 by 250-pixel image nicknamed “Meadow Elves,” illustrating the system’s proficiency in high-speed, crosstalk-free decoding of complex knot-based optical signals. This demonstration not only validates the theoretical underpinnings of the system but also underscores its practical viability for next-generation optical information technologies.

The LightELF platform also heralds the convergence of singular optics with neuromorphic engineering, offering a versatile and expandable research infrastructure. Its lightweight data architecture and event-driven operation mode make it adaptable to a wide variety of applications beyond communications. These include precision optical sensing, investigations into singularity dynamics within complex light fields, and the metrology of pico-photonic structures, thereby pushing the boundaries of what can be measured, computed, and understood at the smallest scales of light-matter interaction.

Moreover, the technology could play a pivotal role in overcoming current bottlenecks in quantum communication networks and advanced imaging systems where rapid, high-fidelity tracking of light’s phase features is crucial. By harnessing the natural topology embedded in light’s structure, LightELF provides a fundamentally new channel for encoding and manipulating information, potentially revolutionizing how data is processed in both classical and quantum regimes.

The research team emphasizes that the LightELF framework is not only a significant academic achievement but also a practical breakthrough with a wide impact potential. Its asynchronous, event-driven sensor design parallels how biological vision systems process information by focusing on changes rather than static scenes, thus bringing the power and efficiency of neuromorphic vision to the realm of optical physics.

This multidisciplinary innovation invites further exploration at the nexus of physics, engineering, and information science. As the technology matures, it promises to spawn new devices and protocols optimized for the unique advantages of optical singularities—high-capacity, topologically encoded information channels that overcome noise, interference, and traditional detector limitations.

In essence, LightELF does not simply add another technique to the toolbox of photonics; it redefines the fundamental approach to how light can be sensed, understood, and harnessed. This advancement unlocks a vibrant research frontier where the esoteric mathematics of topology becomes the basis for practical, high-throughput optical communication and sensing technologies that may soon underpin the future internet, secure communication systems, and beyond.

As the scientific community continues to delve into the complexities of structured light, LightELF offers a beacon of innovation, illuminating pathways toward the ultimate dream—using the darkness of light itself as a high-speed, precise carrier of information. This breakthrough stands as a testament to the power of interdisciplinary collaboration and the enduring potential of nature-inspired engineering solutions in addressing some of the most compelling technological challenges of our time.

Subject of Research: Lab-produced tissue samples

Article Title: Neuromorphic vision of optical darkness for high-throughput topological knot signal processing

News Publication Date: 23-Mar-2026

Web References:
DOI link to article

References:
Weng et al., PhotoniX, 2026, DOI: 10.1186/s43074-026-00235-5

Image Credits:
Weng et al., doi 10.1186/s43074-026-00235-5

Keywords

Structured light, optical singularities, topological knots, neuromorphic photonics, event-driven detection, logarithmic gradient processing, high-throughput optical transmission, phase singularities, optical vortices, optical communication, singular optics, photon metrology

Whispering-gallery mode (WGM) resonators, known for their ability to trap light via continuous internal reflection along curved surfaces, have been a subject of intense research due to their ultra-high quality (Q) factors and compact geometries. These features enable sensitive detection of minute physical changes within or near the resonator, making WGMs invaluable for applications ranging from biosensing to lasing. However, integrating active materials capable of modulating light’s polarization state within these resonators has posed significant challenges. The recent integration of graphene—a two-dimensional allotrope of carbon with extraordinary electrical and optical characteristics—addresses this challenge head-on.

Graphene’s unique electronic band structure endows it with remarkable tunability under external stimuli, including electrical gating and optical pumping. Its broadband absorption combined with fast carrier dynamics enables rapid modulation of optical signals, while its anisotropic response to polarized light offers a gateway to polarization-sensitive functionalities. By seamlessly embedding graphene layers onto the surface of microtubular WGM resonators, the researchers achieved a symbiotic system where the resonator confines light intensely along the curved surface, and graphene actively modulates its polarization and intensity.

The microtube architecture utilized in this study distinguishes itself by providing a quasi-three-dimensional pathway for light propagation, strengthening the coupling between the optical mode and the graphene layer. This design contrasts the traditional planar geometries, resulting in enhanced light–matter interaction strengths. The resonator’s dimensions are meticulously engineered to sustain whispering-gallery modes that overlap strongly with the monolayer or few-layer graphene, maximizing the modulation depth and detection sensitivity.

Polarization sensitivity in optical devices is a critical parameter for numerous applications including data encoding in fiber-optic communication, polarization-division multiplexing, and advanced imaging systems. The reported device capitalizes on the inherently anisotropic absorption and refractive index modulation of graphene when subjected to polarized light, thereby enabling the dynamic manipulation of both the amplitude and phase of the guided light. This capability is realized by electrically tuning the Fermi level of graphene, which adjusts its optical conductivity and thus influences how the WGM resonator interacts with different polarization states.

Photodetection based on graphene has been a rapidly evolving field owing to graphene’s ultrafast photoresponse and broad spectral coverage from ultraviolet to terahertz. Here, the integration with microtube WGM resonators amplifies the interaction length of incident photons with the active material without necessitating bulky device sizes. The enhanced absorption within the resonator boosts the photocurrent generation efficiency, all while maintaining compatibility with existing photonic circuitry. Consequently, the device showcases not only modulation capabilities but also sensitive photodetection functions in a single compact platform.

Importantly, the researchers demonstrate the ability to selectively modulate transverse electric (TE) and transverse magnetic (TM) whispering-gallery modes, a feat that markedly elevates the control over the light polarization state within the resonator system. The modulation depth reached is substantial, evidencing the effectiveness of the graphene integration. Moreover, the device maintains high-quality factors, a testament to the precise fabrication techniques and the minimal introduction of optical losses during the graphene transfer process.

Fabrication involved advanced layer transfer techniques to position graphene uniformly onto microtube resonators fabricated from high-quality dielectric materials. The combination ensures mechanical stability, chemical inertness, and excellent optical confinement. Furthermore, the device operates effectively at room temperature, highlighting its potential for practical applications beyond laboratory settings. The research team also conducted comprehensive optical characterization, including transmission spectroscopy, polarization analysis, and photocurrent measurements, validating the device’s multifunctional capabilities.

This advancement creates exciting prospects for next-generation integrated photonic circuits where multifunctionality, miniaturization, and enhanced performance converge. Optical modulators and detectors that can operate based on polarization states reduce system complexity and offer new dimensions of data processing. The compact footprint of the microtube-graphene hybrid device is particularly relevant for on-chip technologies where space is at a premium.

Beyond telecommunications, the described platform holds promise for optical sensing applications. The sensitivity to polarization states means that environmental changes affecting the refractive index or inducing strain in graphene could be detected with high precision. Such capabilities could, in the future, lead to novel biosensing or chemical detection devices that operate with exceptional speed and sensitivity.

The team also explores potential routes to scalability and integration with other two-dimensional materials, suggesting that the heterostructure-based approach could yield tailored device responses for diverse applications. Given graphene’s compatibility with flexible substrates and its robustness, these resonators may eventually find roles in wearable or implantable photonic sensors.

The interplay between graphene’s electronic properties and the photonic confinement in microtube WGM resonators underscores a broader trend in the field of nanophotonics: the exploitation of low-dimensional materials to engineer light–matter interactions at unprecedented scales and efficiencies. The implementation showcased here exemplifies how fundamental material properties translate into practical device functionalities that could reshape optical technologies.

Moving forward, challenges such as improving the uniformity of graphene coverage, further reducing optical losses, and enhancing modulation speeds constitute natural extensions of this work. The researchers are optimistic that synergistic advances in materials science, nanofabrication, and device engineering will address these hurdles. As such, the principles established here lay a solid foundation for multifaceted photonic devices that integrate modulation, detection, and polarization control in ways previously unattainable.

In summary, the study by Cai and colleagues presents a compelling innovation: graphene-integrated microtube whispering-gallery mode resonators that enable efficient polarization-sensitive optical modulation and photodetection within a compact geometry. This work not only demonstrates significant progress in device performance but also signals the dawn of versatile photonic components crucial for the future of optical communication, sensing, and information processing systems.

Subject of Research: Graphene-integrated microtube whispering-gallery mode resonators for polarization-sensitive optical modulation and photodetection.

Article Title: Graphene-integrated microtube whispering-gallery mode resonators for polarization-sensitive optical modulation and photodetection.

Article References:
Cai, T., Zhang, Z., Wu, B. et al. Graphene-integrated microtube whispering-gallery mode resonators for polarization-sensitive optical modulation and photodetection. Light Sci Appl 15, 130 (2026). https://doi.org/10.1038/s41377-025-02097-1

Image Credits: AI Generated

DOI: 10.1038/s41377-025-02097-1 (Published 28 February 2026)

Fundamentally, second-harmonic generation is a nonlinear optical process where two photons of the same frequency combine within a nonlinear medium to produce a single photon at twice the frequency. Traditionally, engineering the spectral or spatial properties of such nonlinear generation required independent control mechanisms, often confined to specific device dimensions. The latest research overcomes these limitations by exploiting the full two-dimensional programmability of the quadratic nonlinear susceptibility distribution—denoted as χ^(2)—inside a photonic waveguide.

The heart of the innovation lies in the design and projection of specially tailored patterns onto the nonlinear waveguide, which is then pumped with broadband ultrafast pulses. These patterns correspond to precisely engineered quasi-phase-matching (QPM) gratings that vary both longitudinally and transversely. By superimposing different grating structures, the researchers have devised a method to simultaneously sculpt the spatial distribution and spectral content of the generated SH light, forging a versatile platform for spatio-spectral holography on a chip.

Experimentally, the setup utilized involves a sophisticated combination of a reflective grating and a 4f imaging configuration, allowing for the capture of spectrally resolved spatial profiles in one dimension. This arrangement enables the simultaneous measurement of wavelength-dependent spatial intensity distributions of the SHG output with exceptional resolution. The waveguide was excited with pulses of approximately 60-femtosecond duration at a 100-MHz repetition rate, with an on-chip average pump power of about 40 milliwatts and a bias voltage calibrated at 600 volts to optimize nonlinear interaction.

The first demonstration involved the generation of distinct spatial intensity peaks at five specific output wavelengths. By designing QPM patterns with different longitudinal periods and strategically modulating the transverse domain, the team created a spatio-spectral hologram where the number of generated spatial peaks increased with wavelength. The resulting hyperspectral images showcased clearly resolved Gaussian peaks, each localized at predetermined spatial coordinates along the waveguide and tuned to their designated harmonic wavelength. This level of control not only validates the programmability of the system but also opens pathways toward multi-channel frequency conversion and multiplexed optical functionalities on a monolithic platform.

Expanding on this capability, the researchers sought inspiration from earlier proposals of SHG holography to realize wavelength-dependent Airy beam generation. Airy beams are non-diffracting waveforms exhibiting distinctive asymmetric intensity profiles and self-acceleration, characteristics highly prized in beam shaping and particle manipulation. By combining two QPM grating patterns, each with contrasting cubic spatial chirps and unique longitudinal periodicities, the team successfully generated oppositely chirped Airy beams at two distinct wavelengths. Spatial imaging revealed the hallmark fringes and curved trajectories of the Airy beams, which manifested in inverted orientations correlating to their respective spectral components.

This dual functionality—tailoring both spectral and spatial characteristics of the SHG output via a single, reconfigurable QPM waveguide—demonstrates an unprecedented level of nonlinear wavefront control. It is noteworthy that the approach leverages well-established lithographic and domain-inversion techniques, rendering it highly adaptable to existing photonic manufacturing workflows. The continuous voltage tuning also suggests dynamic reprogrammability, extending its utility to adaptive photonic systems.

From a fundamental physics perspective, the work underscores the profound implications of engineered χ^(2) landscapes. Traditionally, phase matching in nonlinear optics dictates stringent conditions on interacting wavelengths and propagation directions. By crafting complex quasi-phase-matching gratings across two spatial dimensions, the researchers decouple these constraints, enabling multichannel frequency conversion processes to coexist and interact coherently within a compact footprint.

The implications of this technology ripple across various domains. In quantum photonics, where control over photon wavepacket profiles is critical, such programmable nonlinear devices could serve as integrated sources of tailored entangled photon pairs or frequency-converted quantum states. In optical signal processing, the capacity to multiplex spatial and spectral channels dynamically could catalyze new architectures for wavelength-division multiplexing and on-chip spectro-temporal holography.

Moreover, the approach’s versatility hints at future expansion toward higher-order nonlinear processes or coupling with other degrees of freedom, such as polarization or orbital angular momentum, broadening the horizons of on-chip optical manipulation. The synergy of broadband ultrafast pumping and programmable nonlinear media also points toward potential applications in ultrafast spectroscopy and nonlinear imaging, where simultaneous spatial and spectral selectivity enhances signal extraction in complex material systems.

While the present demonstrations operate within specific wavelength bands and experimental configurations, the foundational principles pave the way for scalable implementations across diverse material platforms, including lithium niobate, silicon-based nonlinear waveguides, and emerging 2D materials. Integration with active electronics and control circuitry could also enable real-time modulation and adaptive feedback control of nonlinear optical interactions.

In conclusion, the synergistic tailoring of nonlinear susceptibility profiles across spatial dimensions establishes a versatile paradigm for programmable nonlinear photonics. By harnessing two-dimensional quasi-phase-matching patterns, the researchers have opened a new frontier in the simultaneous manipulation of spatial and spectral properties of frequency-converted light on an integrated platform. This innovation not only enriches the toolbox of nonlinear optics but also lays critical groundwork for future photonic technologies that demand dynamically reconfigurable, multi-dimensional control of light at the chip scale.

Subject of Research: Advanced programmable nonlinear photonics enabling simultaneous spatial and spectral control of second-harmonic generation on a chip.

Article Title: Programmable on-chip nonlinear photonics

Article References:
Yanagimoto, R., Ash, B.A., Sohoni, M.M. et al. Programmable on-chip nonlinear photonics. Nature (2025). https://doi.org/10.1038/s41586-025-09620-9

Image Credits: AI Generated