[10p-N205-1~8] 3.2 材料・機器光学

▲ [10p-N205-5] Development of Perfect absorbers by LaB₆-based Metal-Insulator-Metal Stripes

〇(D)Ngo Ducthien^1,2、Phuoc Toan Tran^1,2、Hai Dang Ngo^1,2、Tadaaki Nagao^1,2 (1.MANA, NIMS、2.Hokkaido Univ.)

キーワード：perfect absorber, plasmonics, thermal emitter

Searching for practical plasmonic materials for state-of-the-art infrared applications has been gaining interest in recent years. Conventional noble metals such as Au, Ag, Al, Cu are well-known plasmonic materials because of their excellent plasmonic properties in the ultraviolet-visible region. However, these metals are not suitable for high-temperature infrared applications due to their low thermal stability. With a high melting point of about 2200°C, LaB₆ is one of the candidates for novel plasmonic materials because of its electrical, optical properties, low work function. Besides, more heat-resistant than conventional metals, LaB₆ is a refractory ceramic material and could be used for infrared thermal application and near infrared plasmonics. In this work, taking advantage of LaB₆, we designed the Metal-Insulator-Metal (MIM) Stripe structure for potential use in thermal emitters. Using sputter deposited LaB₆ films and Reactive Ion Etching (RIE), we successfully fabricated the perfect absorber devices, which could be operated at high temperatures up to 600°C in the atmospheric condition. Furthermore, by varying structural parameters, such as periodicity or stripe length, we can freely design the resonant wavelength in the mid-IR region. The simulated and experimental results were in reasonable agreement, encouraging us to design and fabricate the optical devices based on this material.