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Light underpins many of the technologies that shape modern society, from high-speed optical communications and healthcare to environmental sensing and quantum technologies. At the heart of these advances are semiconductor light sources, including LEDs, lasers, and quantum emitters, which generate precisely controlled light. As photonic technologies become increasingly integrated, miniaturised, and energy-efficient, there is a growing need for compact light sources with enhanced performance and new functionalities.

Theme 1 develops the next generation of semiconductor light sources by combining advances in materials science, meta-optics, and nanofabrication to tailor wavelength, coherence, polarisation, directionality and beam profiles, enabling transformative technologies for communications, sensing, imaging and quantum information. To realise this vision, Theme 1 pursues two complementary research directions: the development of ultra-compact semiconductor light sources and the creation of advanced quantum and nonlinear light sources.

Subprogram 1A – Nanoscale Lasers and Laser Arrays

Sub-theme 1A develops ultra-compact semiconductor LEDs and lasers for on-chip photonic systems. By engineering semiconductor nanostructures, optical cavities and their integration with metasurfaces and meta-optics, researchers create miniature light sources with reduced power consumption, enhanced efficiency and precisely controlled emission characteristics. These devices form the building blocks for densely integrated photonic circuits, enabling next-generation optical communications, sensing, imaging and optical computing.

In 2025, sub-theme 1A continued to advance the frontier of miniaturised meta-optical light sources through strong cross-node collaborations and international partnerships. A major breakthrough was the world’s first demonstration of etching-free bottom-up surface-emitting metasurface lasers based on epitaxially grown InP nanosheet arrays. By carefully engineering cavity asymmetry to support quasi-bound states in the continuum (quasi-BICs), these devices achieved record-high room-temperature lasing efficiencies, bringing metasurface lasers closer to thresholdless operation.

In parallel, we worked with collaborators in the United States to advance InP nanowire photonic crystal surface-emitting lasers (PCSELs), introducing a novel hetero-PCSEL architecture that significantly reduced the lasing threshold. Building on this platform, we extended the design to InAs nanowire PCSELs operating near 3.5 μm, opening new opportunities for integrated mid-infrared photonics. Together with collaborators at Friedrich Schiller University Jena, we also demonstrated far-field beam shaping from optically coupled nanowire pairs, marking an important step towards metasurface lasers with tailorable emission profiles.

Looking ahead, sub-theme 1A will focus on advancing the performance, functionality and versatility of nanoscale semiconductor light sources. Key objectives include demonstrating electrically injected lasing in ultra-compact nanocavities, expanding the accessible wavelength range through emerging material platforms such as narrow-bandgap III–V semiconductors and perovskites, and integrating nanolasers with advanced meta-optical functionalities including beam shaping, beam steering and topological lasing. Together, these efforts will establish new paradigms for generating and controlling light at the nanoscale, underpinning future meta-optical systems for communications, sensing and quantum technologies.

Subprogram 1B – Advanced and Quantum Light Sources

Sub-theme 1B explores light generation beyond traditional semiconductor emitters, spanning quantum light sources and nonlinear optical sources for frequency conversion. By integrating these emitters with meta-optics, researchers precisely tailor light at the nanoscale to enable advanced functionalities for quantum technologies, precision sensing, and next-generation imaging.

In 2025, strong collaborations drove major advances, highlighted by the joint ANU and UTS demonstration of electrically driven single-photon sources. Based on III–V quantum dots embedded in nanowire cavities, these devices combine high brightness with exceptional long-term stability under continuous-wave electrical injection, marking a vital step toward scalable, integrated quantum photonics.

Major advances have also been achieved in quantum light sources based on hexagonal boron nitride (hBN), an atomically thin layered crystal. Atomic-scale defects in this material emit single photons and host electron spins, essential for emerging quantum technologies in secure communications, computing, and sensing. We have discovered new families of these emitters, detailed their spin properties, and controlled their emission by twisting stacked layers to tune colour and integrating them with metasurfaces to dramatically enhance brightness. Building on these advances, we are now incorporating these emitters into on-chip photonic architectures – including moiré photonic crystals, meta-waveguides, and metalenses – laying the foundation for compact and scalable quantum photonic technologies.

Another key focus is generating and controlling entangled photon pairs for quantum applications. In 2025, collaborating with Friedrich Schiller University Jena, researchers demonstrated dynamically tunable entangled photons using an ultrathin InGaP metasurface. By exploiting optical asymmetry, the team achieved picosecond-scale tunability of both spatial and polarisation entanglement simply by changing the pump wavelength, establishing a compact, reconfigurable platform for quantum light sources.

On the non-linear light generation front, our team has successfully demonstrated more than a 200-fold enhancement in short-wave infrared second-harmonic generation using specially engineered InP nanomembranes containing large-area wurtzite–zincblende interfaces. These nanostructures provide a powerful platform for efficient frequency conversion and the development of integrated nonlinear photonic circuits. In a parallel initiative, we are collaborating with partner investigators in Jena and the United States to develop advanced nonlinear meta-optics for up-conversion imaging applications.