An improved transmitting multi-layer thin-film filter

Zhang Ying^a),^b), Qi Hong-Ji^a), Yi Kui^a), Wang Yan-Zhi^a), Sui Zhan^c), Shao Jian-Da^a)†

(a) Transmittance spectrum and (b) angular spectrum of the transmitting ultra-narrow bandpass filter with n = 9 at oblique angle of incidence 30°.