| Popis: |
Improving the coupling efficiency of tapered metallic gaps using spatial amplitude modulation is theoretically investigated. The influences of the critical parameters on the coupling efficiency, such as incident beam width, incident wavelength, and numerical aperture of coupling lens, are analyzed, respectively, and a coupling efficiency increase of about 16.43-fold is obtained by optimizing these parameters. The physical mechanism of the coupling efficiency improvement is further discussed. The substantial improvement of the coupling efficiency via spatial amplitude modulation shows the potential in designing tapered metal-insulator-metal waveguides for field enhancement and nanofocusing. |
