Quarter-Wave Plate Applications
四分之一波片应用
Polarization concepts
索引偏振概念
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HyperPhysics ***** 光与视觉 | R Nave |
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Quarter-Wave Plate四分之一波片
A quarter-wave plate consists of a carefully adjusted thickness of a birefringent material such that the light associated with the larger index of refraction is retarded by 90° in phase (a quarter wavelength) with respect to that associated with the smaller index. The material is cut so that the optic axis is parallel to the front and back plates of the plate. Any linearly polarized light which strikes the plate will be divided into two components with different indices of refraction. One of the useful applications of this device is to convert linearly polarized light to circularly polarized light and vice versa. This is done by adjusting the plane of the incident light so that it makes 45° angle with the optic axis. This gives equal amplitude o- and e-waves. When the o-wave is slower, as in calcite, the o-wave will fall behind by 90° in phase, producing circularly polarized light. 四分之一波长板由一种双折射材料制成，其厚度经过精确调整，使得具有较大折射率的光在相位上滞后90°（即四分之一波长）相对于具有较小折射率的光。该材料被切割成 optic axis 与板的前后面平行。任何垂直入射的线性偏振光都会被分解为两个具有不同折射率的分量。这种装置的一个有用应用是将线性偏振光转换为圆偏振光，反之亦然。这通过调整入射光的平面，使其与 optic axis 成45°角来实现。这会使得o-波和e-波的振幅相等。当o-波较慢，如在方解石中时，o-波会在相位上滞后90°，从而产生圆偏振光。
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Index Polarization concepts Reference Hecht Sec. 8.4 索引 偏振概念 参考 Hecht 第8章第4节 | ||
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Quarter-Wave Plate Applications四分之一波片应用
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Index Polarization concepts 索引偏振概念 | ||
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Linear to Circular Polarization线性到圆极化的转换
 If linearly polarized light is incident on a quarter-wave plate at 45° to the optic axis, then the light is divided into two equal electric field components. One of these is retarded by a quarter wavelength by the plate. This produces circularly polarized light. Incident circularly polarized light will be changed to linearly polarized light. 如果线偏振光以45°角入射到四分之一波长板上，那么光会被分成两个相等的电场分量。其中一个分量因板的效应被延迟了四分之一波长。这会产生圆偏振光。入射的圆偏振光会转变成线偏振光。
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Index Polarization concepts 索引偏振概念 | ||
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