Guided mode resonance-driven photoluminescence enhancement and angular emission control in a 2D dielectric photonic lattice

Utilizing fluorescent emitters with precisely designed nanostructures regulates their emission characteristics, which has great potential in light-emitting devices, biosensing, and quantum technologies. In this context, we propose a large area nanostructured design on a flexible polyethylene terephthalate (PET) substrate by patterning it in a square periodic symmetry and coating it with a TiO₂ thin layer to demonstrate cost-effective photoluminescence enhancement and directionality. The proposed design enables a controlled light emission enhancement of about 110 times from the emitter layer over the array through resonance-mediated light confinement. Such mode confinement leads to an increase in the local density of states, which leads to a 100-fold increase in the Purcell factor. Beyond amplification, the polarization-dependent excitation of GMR modes enables directional coupling of photoluminescence into the radiative zeroth-order channel, resulting in well-defined angular emission profiles, as validated by angle-resolved spectroscopy and back focal plane imaging for both transverse electric and transverse magnetic polarization of incident light. The proposed large-area photonic array on a PET substrate offers potential for incorporation into advanced light-emitting optical devices, owing to its scalability and adaptability for practical applications.