Polarization of Light from Basics to Instruments

Page
6

Slide 51

Mueller matrix of retarders (II)

Half-wave oriented at 0º or 90º

Half-wave oriented at ±45º

Part III: Optical components, retarders

Slide 52

Mueller matrix of retarders (III)

Quarter-wave oriented at 0º

Quarter-wave oriented at ±45º

Part III: Optical components, retarders

Slide 53

Mueller calculus with a retarder

Input light linear polarized (Q=1)

Quarter-wave at +45º

Output light circularly polarized (V=1)

Part III: Optical components, retarders

Slide 54

(Back to polarizers, briefly) Circular polarizers

Input light: unpolarized --- Output light: circularly polarized

Made of a linear polarizer glued to a quarter-wave plate oriented at 45º with respect to one another.

Part III: Optical components, polarizers

Slide 55

Achromatic retarders (I)

Retardation depends on wavelength

Achromatic retarders: made of 2 different materials with opposite variations of index of refraction as a function of wavelength

Pancharatnam achromatic retarders: made of 3 identical plates rotated w/r one another

Superachromatic retarders: 3 pairs of quartz and MgF2 plates

Part III: Optical components, retarders

Slide 56

Achromatic retarders (II)

Part III: Optical components, retarders

=140-220º

not very achromatic!

= 177-183º

much better!

Slide 57

Retardation on total internal reflection

Total internal reflection produces retardation (phase shift)

In this case, retardation is very achromatic since it only depends on the refractive index

Application: Fresnel rhombs

Part III: Optical components, retarders

Slide 58

Fresnel rhombs

Quarter-wave and half-wave rhombs are achieved with 2 or 4 reflections

Part III: Optical components, retarders

Slide 59

Other retarders

Soleil-Babinet: variable retardation to better than 0.01 waves

Nematic liquid crystals . Liquid crystal variable retarders . Ferroelectric liquid crystals . Piezo-elastic modulators . Pockels and Kerr cells .

Part III: Optical components, retarders

Slide 60