How can we explain the effect of the real and imaginary part of a dielectric constant?
Under what conditions is the imaginary part of the dielectric constant most effective?
Dear Honorable:
You have to understand the idea that the real part of the dielectric constant relates to the refractive index of the medium you are studying, whereas the imaginary part of the dielectric is related to the energy dissipation factor (extinction coefficient) (i.e. the amount of energy dissipated in the medium by the scattering centers). When you understand this idea, you will find things very easy. Please read the titled researches below:
The precise role of UV exposure time in controlling the orbital transition energies, optical and electrical parameters of thermally vacuum evaporated Se 50 Te 50 thin film
The main role of bismuth in controlling linear and nonlinear optical, electronic and electrical parameters of Se–Ge–Bi thin films
Optical and electronic properties for As-60 at.% S uniform thickness of thin films: Influence of Se content
The main role of thermal annealing in controlling the structural and optical properties of ITO thin film layer
Sn-induced changes in the structure and optical properties of amorphous As–Se–Sn thin films for optical devices
Masoud Mohammadi Ammar Qasem
I would turn this comment around 'the real part of the dielectric constant relates to the refractive index of the medium you are studying, whereas the imaginary part of the dielectric is related to the energy dissipation factor'.
Refractive index is related to the dielectric constant by a square root relation:
n2 = er
where n is the refractive index and er the relative permittivity (or dielectric constant) for non-magnetic materials. The excellent general book I recommend is H A Lorentz The Theory of Electrons available as a Dover reprint at a good price. In particular pages 144 and 145 dealing with the interaction of light with matter and Maxwell's equations. I briefly mention this and show an extract from the pages in a webinar (the slide at 38:00) (registration required) :
Laser Diffraction Masterclass 2: How Can Material Optical Properties be Calculated/Estimated
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W200317LDBasics2.html
As explained above the imaginary part relates to light (or energy) lost in the system and the real part relates to the changes in velocity of light when it travels from one medium or another. There's nothing 'imaginary' about the imaginary parameter; it's simply that the math is easiest to manipulate in complex arithmetic.
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