 | Download THz Waveplates Datasheet (PDF, 60 KB) |
Polarimetry technique is very important for analyzing the THz radiations (divergence, spatial or frequency modes, and profiles). The key instrument in polarimetry is polarization modulator which identifies and measures polarized signal.
Plano-plano plates, made of birefringent material, are used for modifying polarization state of radiation. A waveplate works by shifting the phase between two perpendicular polarization components of the wave. The most common types of waveplates are a half-wave plate (λ/2 plate) and a quarter-wave plate (λ/4 plate). λ/2 plate gives phase delay π and λ/4 plate - π/2. A half-wave plate changes the polarization direction of linear polarized light. A quarter-wave plate changes linearly polarized light to circular and vice versa.
Waveplate will not change the polarization of linearly polarized beam if the polarization direction is along one of waveplate axes.
Operating principle of half-wave and qurter-wave plates is shown below:
| Half-wave plate | Quarter-wave plate |
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Tydex offers the following THz waveplates for single operation wavelength:
Common specification:
| Material | THz grade crystal quartz | | Orientation | X-cut | | Orientation tolerance, arc. min. | +/-10 | | Dimensions tolerance, mm | +/-0.25 | | Clear aperture, % | >=90 | | Parallelism, arc.sec. | 5 | | Surface quality, scr/dig | 60/40 | | TWD, L@633nm | 1/2 |
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Monochromatic THz waveplates available from our stock are listed below:
Retardation
type, λ | Dimensions,
mm | Operation
wavelength, μm | 1/2 & 1/4 | 20x20 | 35.0 | | 76.0 | | 90.5 | | 148.0 | | 280.0 | | 385.0 | | 496.0 | 1/2 | 50x50 | 118.0 | | 242.0 | | 288.0 | 1/4 | 20x20 | 61.5 | 1/2 | 50x50 | 118.0 | | 200.0 | | 210.0 | | 219.2 | | 228.5 |
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