Hyperspectral imaging provides enhanced classification and identification of veiled features in diverse biomedical applications such as label-free cancer detection or non-invasive diagnosis of vascular disease. However, hyperspectral cameras still have technical limitations in miniaturization due to the inherently bulky and complex configurations of conventional tunable filters. Here, we report an active plasmonic tunable filter (APTF) with electrothermally driven spectral modulation for hyperspectral imaging. APTF features angle-sensitive plasmonic structures (APS) over an electrothermal MEMS actuator, fabricated by nanoimprint lithography and subsequent MEMS fabrication at a 6-inch wafer level. APS have a complementary configuration of Au nanohole and nanodisk arrays supported on a silicon nitride thin membrane. APTF shows large angular motion at low operational voltages of 4 - 9 V for continuous and linear spectral modulation between 772 nm and 998 nm (45 nm/V). The compact hyperspectral camera was fully packaged with a linear polarizer, APTF, and a compact monochrome camera, exhibiting a module size of 16 mm (ϕ) × 9.5 mm (h). Augmented subcutaneous vein imaging has been successfully demonstrated after the hyperspectral reconstruction and spectral feature extraction. This work opens up a new direction for a compact hyperspectral camera and expands the scope of HSI to point-of-care or in-vivo imaging, based on high compactness and portability.
초분광이미징은 무표지 암조직 검출이나 혈관 질환의 비침습적 진단 등 바이오메디컬 분야에서 다양하게 활용되어지고 있는 기술이다. 하지만, 기존의 초분광이미징 시스템 즉, 초분광 카메라에서 핵심 광학 소자로 사용되고 있는 가변 분광 필터는 분광 원리 상 본질적으로 부피가 크거나 복잡한 구성을 가지고 있기 때문에 소형화에 한계가 있는 실정이다. 본 연구에서는 각감응 나노구조 기반의 초소형 대면적 능동 플라즈모닉 가변 분광 필터를 개발하고, 이를 이용한 소형 초분광카메라 패키징 및 초분광이미징 응용 가능성을 검증하고 한다.
