“…8,9 As compared with IMI structures, MIM structures have smaller spatial size and restricted nanoscale mode sizes, which has obvious advantages for high-density integrated platforms. [10][11][12] Many MIM devices have been studied, such as all-optical switches, 13 Y-shaped combiners, 14 reflectors, 15 SPP resonance sensors, 16 waveform modulators, 17 temperature sensors, 18 and in particular, various filters. [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] Among all these devices, SPP filters play unique and important roles in integrated SPP platforms.…”