optical medium

The optical medium has an intrinsic impedance, given by

::$\backslash eta\; =\; \{E\_x\; \backslash over\; H\_y\}$

where $E\_x$ and $H\_y$ are the electric field and magnetic field, respectively.

In a region with no electrical conductivity, the expression simplifies to:

::$\backslash eta\; =\; \backslash sqrt\{\backslash mu\; \backslash over\; \backslash varepsilon\}\backslash \; .$

For example, in free space the intrinsic impedance is called the characteristic impedance of vacuum, denoted Z₀, and

::$Z\_0\; =\; \backslash sqrt\{\backslash mu\_0\; \backslash over\; \backslash varepsilon\_0\}\backslash \; .$

Waves propagate through a medium with velocity $c\_w\; =\; \backslash nu\; \backslash lambda$, where $\backslash nu$ is the frequency and $\backslash lambda$ is the wavelength of the electromagnetic waves. This equation also may be put in the form

:$c\_w\; =\; \{\backslash omega\; \backslash over\; k\}\backslash \; ,$

where $\backslash omega$ is the angular frequency of the wave and $k$ is the wavenumber of the wave. In electrical engineering, the symbol $\backslash beta$, called the phase constant, is often used instead of $k$.

The propagation velocity of electromagnetic waves in free space, an idealized standard reference state (like absolute zero for temperature), is conventionally denoted by c₀:With ISO 31-5, NIST and the BIPM have adopted the notation c₀.

:$c\_0\; =\; \{1\; \backslash over\; \backslash sqrt\{\backslash varepsilon\_0\; \backslash mu\_0\}\}\backslash \; ,$

:where $\backslash varepsilon\_0$ is the electric constant and $~\; \backslash mu\_0\; \backslash$ is the magnetic constant.

For a general introduction, see Serway

{{cite book |author1 = Raymond Serway

|author2 = Jewett J

|name-list-style = amp

|title = Physics for scientists and engineers

|edition = 6th

|year = 2003

|publisher = Thomson-Brooks/Cole

|location = Belmont CA

|isbn = 0-534-40842-7

|url = https://archive.org/details/physicssciengv2p00serw

|url-access = registration

}}

For a discussion of synthetic media, see Joannopoulus.

{{cite book

|author1=John D Joannopouluos |author2=Johnson SG |author3=Winn JN |author4=Meade RD |title=Photonic crystals : molding the flow of light

|edition=2nd

|year= 2008

|publisher=Princeton University Press

|location=Princeton NJ

|isbn=978-0-691-12456-8

|url=http://ab-initio.mit.edu/book/}}

• Čerenkov radiation
• Electromagnetic spectrum
• Electromagnetic radiation
• Optics
• SI units
• Free space
• Metamaterial
• Photonic crystal
• Photonic crystal fiber

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Category:Optics

Category:Electric and magnetic fields in matter