Joel Kwang Wei Yang

Pseudo‐Binary GeTe‐Sb ₂ Te ₃ materials have demonstrated promising thermoelectric performance in intermediate temperature (500‐800 K) range. In this work, by co‐sputtering of Ge ₄₅ Te ₅₂ S ₃ and Sb ₂ Te ₃ a composition spreads with varying Ge:Sb:Te ratios were fabricated to identify specific composition regimes with the highest thermoelectric performance. From the thermoelectric measurements, (Ge ₅ Sb ₃₇ Te ₅₈ ) demonstrated the highest power factor values. Thermal conductivity measurements were performed on the different compositions with higher power factor values. Maximum zT values ranging from 0.36 ± 0.08 to 0.81 ± 0.15 for samples Ge ₉ Sb ₃₃ Te ₅₈ to Ge ₅ Sb ₃₇ Te ₅₈ at 300°C were achieved. The co‐sputtering technique establishes an effective high‐throughput approach to systematically map the relationship between composition and thermoelectric properties across a wide range of compositions in a single deposition run.

Quantum emitters (QE) weakly coupled to plasmonic cavities are known to exhibit scattering spectra that are largely indistinguishable from those in the absence of the emitters themselves. Here, we report a strong fluorescence peak visible in dark-field spectra of gap plasmons. This emission arises under incoherent white-light excitation from a few emitters in a monolayer of nanoplatelets (NPLs) within nanoparticle-on-mirror (NPoM) cavities. Single-NPoM spectra reveal an intense 650 nm peak from a few NPLs, matching their fluorescence and confirmed as emission by quenching and detuning controls. Simulations resolve the dipole mismatch of face-down NPLs: the bright cavity mode feeds dark modes whose in-plane corner fields drive the excitons. The 650 nm peak grows linearly with excitation power, as photoluminescence does, and at nearly twice the rate of scattering. The NPoM chip appears red to the naked eye under focused sunlight, at irradiances about seven orders of magnitude lower than conventional focused-laser excitation. Dark-field spectra of emitter-loaded nanocavities carry both scattering and emission, enabling laser-free few-emitter spectroscopy and sunlight-driven nanophotonics.

Conventional print is noninteractive, whereas modern electronic displays, even with improved energy efficiency, require continuous power input and generate electronic waste. Here, we report morphing polymeric voxels based on liquid crystal that enable seamless and reversible information display without onboard electrical power or integrated circuitry. Each voxel exhibits programmable dual birefringence arising from geometry-defined structural anisotropy and mesogen-defined material anisotropy. By mapping laser-writing angle and power, two distinct images are encoded within a single array. Mechanical deformation induces voxel buckling and hybrid director fields, reversibly switching brightness dominance between the two birefringence channels. This deformation-driven mechanism enables reversible transitions between preencoded images. Comprising only polymers and relying on passive optical modulation, the platform establishes a sustainable route toward circuit-free dynamic displays.

Tailoring light-matter interaction using photonic modes depends on both the spectral and spatial overlap between the modes and quantum emitters, which is critical for optimizing light-matter coupling and enabling efficient, controllable emission. Here, we demonstrate deterministic control of emission from colloidal quantum dots (CQDs) integrated into dielectric light-emitting metasurfaces (LEMs) by precisely localizing the emitters at the field maxima of the photonic modes across the entire metasurface. Numerical simulations show that deterministic localization enhances the emission, yielding a higher emission enhancement factor than that of LEMs with randomly distributed emitters. Experimentally, such global spatial overlap is achieved using a single-template lift-off process to localize the CQDs at the desired positions. Optical characterization confirms efficient coupling between CQD emission and the photonic modes, resulting in a narrowed spectral linewidth and highly directional out-of-plane emission. Deterministic emission control in metasurfaces adds a new degree of freedom to LEM design, paving the way for an efficient integrated light source for classical and quantum photonic devices.

Color imaging systems that underpin modern technologies still suffer in low-light conditions because of the inherently lossy filtering mechanism of conventional Bayer color filters. Although Bayer-type filters integrated with complementary metal–oxide–semiconductor sensors remain the dominant architecture, they typically transmit only about 30% of incident white light, leading to noisy images under weak illumination. Color routers offer an alternative by redirecting different spectral components of light to corresponding photodiodes in the near field. While recent color routers based on high-refractive-index metasurfaces have shown promise, low-refractive-index materials remain largely unexplored despite their potential for higher transmittance and cost-effective mass production. Here, we demonstrate inverse-designed, two-photon-polymerization 3D-printed pixel-level color routers using low-index IP-L resin (n ≈ 1.5). The color routers achieve transmittance of ~87% in simulation and ~70% experimentally across the visible spectrum. Monochrome-sensor imaging further confirms improved color fidelity and shorter exposure times, highlighting their potential for next-generation high-efficiency imaging platforms.

Soft robotics is evolving from a field centered on compliant mechanisms toward a broader paradigm of embodied physical intelligence, in which materials, mechanics, sensing, and computation are deeply integrated. Despite rapid progress, major challenges remain in actuation, perception, autonomy, scalability, and real-world deployment. In this Nano Focus article, we highlight emerging frontiers and technological challenges spanning multifunctional materials, distributed sensing, additive manufacturing, artificial intelligence, and biohybrid systems. Advances in nanoscience and nanotechnology increasingly underpin these developments by enabling the integration of sensing, actuation, and adaptive functionalities across length scales. Collectively, these advances are establishing a foundation for intelligent matter, programmable physical intelligence, and life-like adaptive systems.

Achieving ultralow optical loss, broadband transparency, and mechanical softness within a single polymer network remains a long‐standing challenge for soft photonics. Here, we report a molecularly engineered class of UV‐curable thiol‐ene‐aromatic polymers that reconciles optical performance with mechanical compliance. By combining thiol crosslinkers with aromatic acrylates to form a low‐absorption network and introducing a phenyl‐bearing comonomer to mitigate near‐infrared vibrational overtone absorption while tuning elasticity and printability, the optimized A50 formulation exhibits ultralow optical attenuation of ∼0.004 dB cm ^{− 1} , together with broadband transparency from 310 to 1100 nm and transmittance exceeding 90% above 380 nm at millimeter‐scale thicknesses. The same formulation remains mechanically compliant and supports high‐fidelity freeform UV‐based 3D printing, while exhibiting high thermal stability (onset ≈333°C). Leveraging this combination of optical and mechanical properties, we demonstrate deformable waveguides and bioinspired optomechanical devices capable of robust, multichannel optical sensing under repeated low‐force interactions and compliant manipulation. This work establishes a molecular design strategy for creating soft polymers with ultralow optical loss, providing a materials platform for next‐generation soft photonic interfaces and adaptive robotic systems.

Light beams carrying orbital angular momentum (OAM) possess an unbounded set of orthogonal modes, offering significant potential for optical communication and security. However, exploiting OAM beams in space has been hindered by the lack of a versatile design toolkit. Here, we demonstrate a strategy to tailor OAM across multiple transverse planes by shaping optical caustics leveraging on catastrophe theory. With 3D-printed metasurfaces fabricated using two-photon polymerization lithography, we construct these caustics to steer Poynting vectors and achieve arbitrary shapes of OAM beams. Interestingly, we further realize “hidden” OAM along the propagation trajectory, where the intensity of the beam is spread out thus avoiding detection. By exploiting this intrinsic nature of OAM, we demonstrate the detection of encoded information in optical encryption. Our approach provides a unique framework for dynamic control of OAM in space, with promising applications in optical trapping and sensing, high-capacity data storage, and optical information security.

Metasurfaces offer unique advantages in manipulating the dispersion of optical fields; yet the achievable dispersion of metasurfaces has long been constrained by the limited phase modulation of complex nanostructures. Here we introduce a metasurface design method based on convergence phase that enables ultra-dispersive metasurfaces using structurally simple nanopillars with relaxed fabrication requirements. By overlapping phase of multiple wavelengths with that of a central wavelength, we demonstrated an ultra-dispersive metalens supporting phase variations exceeding 1200π - a more than 30-fold enhancement over existing approaches. Leveraging this method, we fabricated metalenses that exhibit unprecedented dispersion characteristics and implemented the metalens in a miniaturized chromatic confocal sensor for a measurement range of 13 mm with an axial resolution of 50 nm. Additionally, we demonstrated millimeter-scale depth-of-field spectral tomography, highlighting the significant advantage and immense potential of our method. Our research has established a generalizable theoretical foundation for designing ultra-dispersive metasurfaces that can be mass-produced and deployed for practical applications.