Each total internal reflection can induce 1/8 phase shift. The Fresnel Rhombs utilize the total internal reflection to generate the desired phase retardation. For example, one Fresnel Rhomb can generate 1/4 wave retardation, and two rhombs in series can create 1/2 wave retardation. The most common materials are BK-7 glass, CaF2, fused silica and ZnSe.

United Crystals' Fresnel Rhombs meet the following specifications:

Retardation Tolerance: <2%

Surface Quality: 20/10 scratch dig

Parallelism: <1 arc min

Diameter Tolerance: +0.0/-0.1mm

Retardance: λ/2 and λ/4

AR-coating: available upon request

For more information, please feel free to contact the United Crystals' technical support team.