Brewster prism
A Brewster prism is an optical prism in which the light hits one or more surfaces of the prism at a Brewster angle and is therefore either not or only partially reflected , depending on the polarization .
Brewster prisms are used when using polarized light. They offer the advantage here that the component of the light polarized parallel to the plane of incidence is transmitted into the prism with almost no reflection losses. For this reason, there is no need for an anti-reflective coating with this type of prism . This also means that there are almost no scattered reflections, which is particularly advantageous in high-performance applications with laser beams.
Typical prism geometries are the equilateral dispersion prism (60 ° prism) and the Pellin-Broca prism , in which an additional total reflection in the prism causes a beam deflection. In both cases, the light beam hits the interface at both the entry and exit at Brewster's angle. The total beam deflection is 90 °, with other prismatic geometries or beam paths also being able to cause a beam deflection by 180 ° or a multiple of the Brewster angle. Due to dispersion , this effect can only be achieved precisely for one wavelength. Brewster prisms are therefore mainly used in laser applications , for example for line selection.
literature
- M. Cervantes: Brewster angle prisms: a review . In: Optics & Laser Technology . tape 20 , no. 6 , November 1988, pp. 297-399 , doi : 10.1016 / 0030-3992 (88) 90058-8 .
Individual evidence
- ↑ Wolfgang Demtröder: Laser spectroscopy: Basics and techniques . Springer, 2007, ISBN 978-3-540-33792-8 , pp. 178 .