Fabrication of quarter THz wavelength resonant cavity using a multiple spin coating process

Due to the long terahertz (THz) wavelength, it remains a challenging problem to achieve THz wave absorption through building an effective optical resonant cavity for THz wave with THz focal plane arrays. In this paper, a multiple spin coating (MSC) process was developed for the first time to increase the height of the optical resonant cavity. Four resonant cavities with different heights were fabricated and their abilities to absorb THz waves were tested respectively. The tests suggested that the different THz bands were absorbed effectively by the micro-bridge structure using the proposed MSC process.