Hi, i am modeling my unit cell structure (plasmonic rectangular slit) in COMSOL with silver metal as top layer and ITO as substrate. My transmittance, |S21|^2 is too small , ~ 6%. I have interpolated my silver and ITO properties within the optical wavelength (400nm to 750nm) but my transmittance isn't improving.
What are some of the ways of dealing with Loss at these frequencies in COMSOL? Anyone who has modeled a device for transmittance, what could i be missing, is there any specific thing i can do to increase the transmittance?
You can regulate and control the transmission intensity by changing your structure parameters such as the length, width of your slit, the period of unit cell and the thickness of the sliver layer. the picture I uploded is an example for gold rectagular slit which is based on my research dates. Ps: for simulation with comsol, the correctness of mesh setting need to be vertified carefully for a credible results, so I proposed a paper of Ag based nano slit to provide a reference for your further duplication.
I hope my answer can help you.
Article Manipulating light polarization with ultrathin plasmonic metasurfaces
Thank you so much Zhangcheng Li, this is indeed a very good information. I want to try it and share my findings.
Hi Zhangcheng Li,
Thanks once again, i managed to increase my transmittance to 65% by using the analytic equation in the attached paper in stead of the interpolated data. However, in the DRUDE model equation, the denominator sign is supposed to be positive in the second term, why is it that others use it as negative? How does this influence the loss in Ag. Anyone with an idea? i mean this equation..(see below).
In comsol, the default form of refractive index is ε1-iε2, thus it require that the denominator sign should be set in the form of negative in the second term.
For positive one , change the sign to negitive in your setting .
Moreover, when you set the permittivity of Ag, you need to make sure the method you using is in accord with the waveband which you are care about.
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