Incandescent Light Bulbs Based on a Refractory Metasurface

• Main Authors: Hirofumi Toyoda, Kazunari Kimino, Akihiro Kawano, Junichi Takahara
• Format: Article
• Language: English
• Published: MDPI AG 2019-10-01
• Series: Photonics
• Subjects: incandescent light bulb; thermal radiation; refractory metal; microcavity; metamaterial; metasurface; surface plasmon; infrared emitter; nanoimprint
• Online Access: https://www.mdpi.com/2304-6732/6/4/105

A thermal radiation light source, such as an incandescent light bulb, is considered a legacy light source with low luminous efficacy. However, it is an ideal energy source converting light with high efficiency from electric power to radiative power. In this work, we evaluate a thermal radiation light source and propose a new type of filament using a refractory metasurface to fabricate an efficient light bulb. We demonstrate visible-light spectral control using a refractory metasurface made of tantalum with an optical microcavity inserted into an incandescent light bulb. We use a nanoimprint method to fabricate the filament that is suitable for mass production. A 1.8 times enhancement of thermal radiation intensity is observed from the microcavity filament compared to the flat filament. Then, we demonstrate the thermal radiation control of the metasurface using a refractory plasmonic cavity made of hafnium nitride. A single narrow resonant peak is observed at the designed wavelength as well as the suppression of thermal radiation in wide mid-IR range under the condition of constant surface temperature.