What is optic retardance?

Waveplates, also known as retarders, transmit light and modify its polarization state without attenuating, deviating, or displacing the beam. In unpolarized light, waveplates are equivalent to windows – they are both flat optical components through which light passes.

What does a half Waveplate do?

Half-waveplates can be used to rotate the plane of linearly polarized light as shown in Figure 3. Figure 3. A half-waveplates rotating the plane of linearly polarized light. This describes a linearly polarized wave, but making an angle θ on the opposite side of the fast axis.

What is fast and slow axis?

A waveplate works by shifting the phase between two perpendicular polarization components of the light wave. This leads to a phase difference between the two components as they exit the crystal. When ne < no, as in calcite, the extraordinary axis is called the fast axis and the ordinary axis is called the slow axis.

What is half-wave crystal?

Thorlabs’ Half-Wave Liquid Crystal Variable Retarders (LCVR) use a nematic liquid crystal cell to function as a variable wave plate. The absence of moving parts provides quick switching times on the order of milliseconds (see the Switching Time tab for details). Thorlabs offers Ø10 mm and Ø20 mm clear aperture sizes.

What is the retardance of a wave plate?

Wave plates are typically available with a retardance of λ/4 or λ/2, meaning that a phase shift of a quarter wavelength or a half a wavelength (respectively) is created. As described above, a wave plate has two principal axes: fast and slow.

How is one full wave of retardation equivalent to 360°?

One full wave of retardation is equivalent to 360°, or the number of nanometers at the wavelength of interest. Tolerance on retardation is typically stated in degrees, natural or decimal fractions of a full wave, or nanometers. Examples of typical retardation specifications and tolerances are:

What is the symbol for free space wavelength?

Unfortunately, the symbol λ is ambiguous because some texts and journal articles use λ to mean the free space wavelength. Others use it as the wavelength that can change depending on the speed of the wave. Usually λ 0 is used for the specific case of vacuum wavelength. The moral is, be careful.

What is the origin of the wavelength symbol?

If you are referring to “λ” which is the symbol mainly used for the wavelength of electromagnetic waves, its origin isn’t clear. It is most likely used because in Greek it is the equivalent of the letter “L”, the first letter of the words light (Latin lux) and length.