[1] ABBE E. Gesammelte abhlungen III[M]. Jena: B, 1906.
[10] LIEWALD C, MASTEL S, HESLER J. All-electronic terahertz nanoscopy[J]. Optica, 5, 159-163(2018).
[11] KNOLL B, KEILMANN F. Enhanced dielectric contrast in scattering-type scanning near-field optical microscopy[J]. Optics Communications, 182, 321-328(2000).