Resonantly Enhanced Emission from a Luminescent Nanostructured Waveguide.

Controlling the characteristics of photon emission represents a significant challenge for both fundamental science and device technologies. Research on microcavities, photonic crystals, and plasmonic nanocavities has focused on controlling spontaneous emission by way of designing a resonant structure around the emitter to modify the local density of photonic states. In this work, we demonstrate resonantly enhanced emission using luminescent nanostructured waveguide resonance (LUNAR). Our concept is based on coupling between emitters in the luminescent waveguide and a resonant waveguide mode that interacts with a periodic nanostructure and hence outcouples via diffraction. We show that the enhancement of resonance emission can be controlled by tuning the design parameters. We also demonstrate that the enhanced emission is attributable to the accelerated spontaneous emission rate that increases the probability of photon emission in the resonant mode, accompanied by enhanced the local density of photonic states. This study demonstrates that nanostructured luminescent materials can be designed to exhibit functional and enhanced emission. We anticipate that our concept will be used to improve the performance of a variety of photonic and optical applications ranging from bio/chemical sensors to lighting, displays and projectors.

Diffraction light analysis method for a diffraction grating imaging lens.

We have developed a new method to analyze the amount and distribution of diffraction light for a diffraction grating lens. We have found that diffraction light includes each-order diffraction light and striped diffraction light. In this paper, we describe characteristics of striped diffraction light and suggest a way to analyze diffraction light. Our analysis method, which considers the structure of diffraction grating steps, can simulate the aberrations of an optical system, each-order diffraction light, and striped diffraction light simultaneously with high accuracy. A comparison between the simulation and experimental results is presented, and we also show how our analysis method can be used to optimize a diffraction grating lens with low flare light.

Phase function design of a diffraction grating lens for an optical imaging system from a Fraunhofer diffraction perspective.

The potential exists to apply diffraction gratings to optical imaging systems to improve camera resolution and shorten optical length. However, we have noted the generation of striped flare lights, which differ from unnecessary-order diffraction lights, under intense lighting. We have elucidated the generation principle of these new striped lights and have discovered that they are caused by narrow diffraction grating rings. In this paper, using an analysis based on Fraunhofer diffraction, we suggest a way of minimizing them by designing an appropriate phase function structure, and test the efficacy of this design using our own manufactured prototype.