Hi Prof.Rumpf, Based on the Drude model, EM wave with the frequency below metal's plasma frequency will be reflected by the metal, and EM wave with the frequency higher metal's plasma frequency will transmit through metal with very little loss. EM wave with the frequency very close to plasma frequency will be lossy. But optical frequencies(< 10^15) usually smaller than plasma frequency (10^16), how come the metals become lossy in slide 25 ?
The plasma frequency is not a sharp cutoff. In fact, it is quite slow and smooth. Thus, metals are still lossy at optical frequencies, but even more lossy at the plasma frequencies usually in the ultra-violet region. Even if the loss of the metals is somewhat low, structures that have resonant metallic elements will amplify that loss because currents are oscillating in those metals and experience more loss with every oscillation.
Let me point you to the official course website. Here you will find links to the videos, the lecture notes, and other resources. empossible.net/academics/emp6303/
Hi Prof.Rumpf, Based on the Drude model, EM wave with the frequency below metal's plasma frequency will be reflected by the metal, and EM wave with the frequency higher metal's plasma frequency will transmit through metal with very little loss. EM wave with the frequency very close to plasma frequency will be lossy. But optical frequencies(< 10^15) usually smaller than plasma frequency (10^16), how come the metals become lossy in slide 25 ?
The plasma frequency is not a sharp cutoff. In fact, it is quite slow and smooth. Thus, metals are still lossy at optical frequencies, but even more lossy at the plasma frequencies usually in the ultra-violet region. Even if the loss of the metals is somewhat low, structures that have resonant metallic elements will amplify that loss because currents are oscillating in those metals and experience more loss with every oscillation.
@@empossible1577 I got it. Thank you very much.
Hi! This is a wonderful presentation. Can you please share the ppt
Let me point you to the official course website. Here you will find links to the videos, the lecture notes, and other resources.
empossible.net/academics/emp6303/
@@empossible1577 Thank You so much. The content is great.
thanks a lot