Over the past twenty years, photonic-crystal surface-emitting lasers have emerged as advanced semiconductor devices with potential uses in defense and aerospace. Most such lasers rely on repeating crystal patterns, yet researchers at the University of Illinois have now created a quasi-periodic version using a buried dielectric platform. The new device offers a path toward more flexible and dependable lasers, as reported in Applied Physics Letters.
A key limitation in the field has been dependence on fixed geometric designs that restrict pattern variety. Graduate student Erin Raftery sought a more adaptable approach by developing a nonperiodic structure inspired by topological patterns. She etched a silicon dioxide layer, later covered by epitaxial semiconductor, producing a partially periodic device that operated successfully at room temperature.
The method provides a practical route to high-performance lasers that are versatile and independent of specific geometries. The team noted greater freedom to adjust refractive index variations for desired laser properties. Current benefits include improved uniformity and the ability to combine different structures on one substrate, potentially yielding more reliable performance.
Future work will focus on electrically injected diodes to demonstrate practical, commercially relevant devices. The researchers have shown the underlying physics and now aim to produce a functional prototype.
