Detect

From smartphones to drones, today’s devices need compact sensors that can “see” more than just visible light. Detecting both visible and infrared light is key for technologies like chemical sensing, 3D imaging, virtual and augmented reality, and even improving visibility in tough conditions like fog or bushfire smoke.

Infrared detectors already play a big role in defence, medicine, and modern industry. But current technology struggles to perform well at room temperature, which makes it harder to use in weight-sensitive platforms such as drones and space systems.

That’s where TMOS comes in. Theme 3 is developing new nanowire-based devices and integrating advanced metasurfaces into detectors to make them smaller, lighter, and more powerful. We’re also unlocking new ways to capture “hidden” details in light—like its polarisation and phase—using meta-optics, giving compact sensors access to information that was once invisible.

The result? A new generation of smart, lightweight sensors ready to transform everyday devices and critical technologies alike.

Sub-theme 3A – Advanced Infrared Imaging

Sub-theme 3A focuses on advancing infrared (IR) detection technologies by developing high-performance materials and devices operating in the short-wave (SWIR) and mid-wave (MWIR) infrared spectrum. The primary goal is to improve the key performance indicators—such as responsivity, detectivity, and noise performance—or introduce novel material systems and device architectures that enable enhanced functionality.

Our team achieved major advances in IR detection, targeting SWIR and MWIR spectrum. These developments push performance benchmarks while introducing new device architectures with broad applications.

Optimised InAs/InP nanowire photodetectors delivered high-speed, broadband, and tunable SWIR detection, establishing a strong platform for future imaging systems. Building on this work, cross-node research between ANU and the University of Melbourne has advanced InAs nanowire arrays towards multi-pixel photodetectors and NIR/SWIR spectral reconstruction. Meanwhile, InAs nanosheet devices achieved a remarkable dichroic ratio of 44 at 2.9 µm with stable room-temperature operation, enabling new opportunities in polarisation imaging. Further work is extending polarisation-sensitive detection through the integration of metasurfaces with InGaAs photodetectors for compact SWIR polarimetric imaging.

A new class of InGaAs nanowire detectors reached single-photon-level sensitivity at 1310 nm, detecting signals as faint as 6.5 pW with a rapid 22 ns response, ideal for high-bandwidth and real-time applications. Further progress came from nanowire quantum well photodetectors, which demonstrated normal-incidence response at 4 µm alongside ultra-low dark current density, significantly improving signal-to-noise.

We have also successfully developed a new type of infrared photodetector—called the nanowire QWIP—that operates in the MWIR range (3–5 μm). Thanks to its unique nanowire design, it can detect light from straight on (normal incidence), which is a major advancement. After careful testing at our UWA node, the device showed strong performance at 4.2 μm, with high sensitivity and low noise—paving the way for future applications in areas like thermal imaging and remote sensing.

Finally, integrating gold metasurface gratings with nanowire QWIPs enabled precise wavelength demultiplexing, paving the way for more selective and tunable IR detection. Research into spectral selectivity has also expanded through the development of guided-mode-resonance filter arrays integrated with thermal infrared cameras for compact mid-IR microspectrometry, alongside tunable silicon zero-contrast-grating filters for narrowband infrared spectral filtering.

Together, these breakthroughs highlight TMOS’s role in shaping the future of infrared sensing through nanowire, nanosheet, and metasurface innovations.

Sub-theme 3B – Hidden properties of light

TMOS Theme 3B is advancing the detection of light’s hidden properties—wavelength, phase, quantum states, polarisation, and angular momentum—that remain invisible to conventional detectors. Metamaterials are central to this effort, offering unprecedented control of light with applications spanning defence, space, healthcare, science, and telecommunications. Building on the success of metasurface-based isometric differential interference contrast imaging, researchers are now exploring polarisation and spectral multiplexing for advanced phase imaging.

Significant progress was made across multiple fronts. At UWA, a plasmonic filter array microspectrometer was characterised using both a micro-bolometer camera and an FTIR microscope, marking an important step toward compact hazardous agent detection. UWA also led the fabrication of MEMS-based gas sensing microspectrometers, with ongoing characterisation supported by spectral reconstruction methods from the University of Melbourne.

Breakthroughs in quantum imaging included entangled photon pair generation from nonlinear metasurfaces and progress toward single-shot 2D ghost imaging. Collaborative efforts with Jena further advanced quantum ghost imaging of phase objects. This work has continued through cross-node research on compact quantum ghost imaging, further developing approaches to retrieve information encoded in quantum-correlated light.

Meanwhile, our team fabricated plasmonic nanogratings for polarisation-sensitive detection, and completed filter components for an EG/SiC mid-infrared edge-detection system. Research in optical feature extraction has expanded to nonlocal metasurfaces, using neural-network-assisted inverse design to engineer angular bandpass responses for phase-contrast microscopy and spatial filtering.

Further advances in multidimensional imaging include topology-optimised diffractive metasurfaces that encode polarisation information across multiple diffraction orders, providing new approaches to compact polarisation analysis.

Beyond imaging, TMOS researchers and collaborators have developed an optical sieve for nanoplastic discrimination, demonstrating the use of nanostructured optical fields to detect and distinguish nanoscale plastic particles.

Together, these results highlight the transformative role of metasurfaces in redefining optical detection.