Verdet constant

The Verdet constant is a material property that indicates the strength of the Faraday effect for a particular substance. Their value depends on the wavelength of the light. The Verdet constant is named after the French physicist Marcel Émile Verdet (1824–1866). In the International System of Units it has the unit rad m ⁻¹ T ⁻¹ . According to convention, a positive Verdet constant stands for a substance that has an anti-clockwise effect on light that spreads parallel to the magnetic field lines. ${\displaystyle \cdot }$ ${\displaystyle \cdot }$

The angle by which the polarization is rotated on the way through a material with the thickness due to the Faraday effect is proportional to the Verdet constant : ${\displaystyle \alpha }$ ${\displaystyle d}$ ${\displaystyle V}$

${\displaystyle \alpha =d\,V\,B}$

It is the magnetic flux density in the material, parallel to the propagation direction of light. ${\displaystyle B}$

The value of the Verdet constant can be calculated from the dispersion of the material under consideration: ${\displaystyle {\frac {\mathrm {d} n}{\mathrm {d} \lambda }}}$

${\displaystyle V(\lambda )={\frac {-e}{m_{e}}}\,{\frac {\lambda }{2c}}\,{\frac {\mathrm {d} n}{\mathrm {d} \lambda }}}$

Here is the wavelength of light, the speed of light , the elementary charge and the mass of the electron . ${\displaystyle \lambda }$ ${\displaystyle c}$ ${\displaystyle e}$ ${\displaystyle m_{e}}$

Verdet constants
Terbium Gallium Garnet	-134 rad T −1 m −1 at 632 nm

Individual evidence

1. ↑ Eugene Hecht: Optics . 5th edition. Oldenbourg Verlag, Munich / Vienna 2009, ISBN 978-3-486-58861-3 , p. 593-594 .
2. ↑ Eugene Hecht: November 8, 2 . In: Optik , 4th edition, Oldenbourg Wissenschaftsverlag, January 31, 2005, ISBN 978-3-486-27359-5 , p. 590 (accessed on February 26, 2012).
3. ↑ Christian Gerthsen: 3/10/4 . In: Dieter Meschede (Ed.): Gerthsen Physik . Springer, August 19, 2003, ISBN 978-3-540-02622-8 , p. 560 (accessed February 26, 2012).
4. ↑ http://www.northropgrumman.com/BusinessVentures/SYNOPTICS/Products/SpecialtyCrystals/Documents/pageDocs/TGG.pdf