Product Search Results
%201.svg)
Fresnel rhombs generate a phase shift not by introducing an optical path difference but by employing the phase difference between the s-polarized and the p-polarized component in total internal reflection. This phase shift shows only minor spectral variation which makes the retarders suited for very broad spectral ranges.
Fresnel rhombs generate a phase shift not by introducing an optical path difference but by employing the phase difference between the s-polarized and the p-polarized component in total internal reflection. This phase shift shows only minor spectral variation which makes the retarders suited for very broad spectral ranges.
We offer Fresnel rhombs made either from fused silica or from crown glass N-BK7. A retardation of λ/4 is achieved by two total internal reflections inside a single parallel epiped. The corresponding half wave retarders consist of two such epipeds which are connected by optical contact.
For the λ/2-rhombs we offer two types of holders. For the first version the rhombs are mounted to a plate. Both ends are equipped with cylindrical attachments for easy integration e.g. in rotation mounts. The second version is mounted on a post and includes a rotating part which is equipped with ball bearings and an angular graduation 0-360°. The λ/4-rhombs are delivered in a cylindrical holder.
| spectral range | 215-450 nm | 400-700 nm | 500-1300 nm | 650-1700 nm |
| material | fused silica | N-BK7 | N-BK7 | N-BK7 |
| deviation of retardation | ±5% | ±1% | ±1% | ±1% |
| wavefront distortion | <λ/4 | <λ/4 | <λ/4 | <λ/4 |
| prismatic deviation | <2'' | <2'' | <2'' | <2'' |
| beam offset (λ/4 only) | 12.6 mm | 13.6 mm | 13.4 mm | 13.2 mm |
| reflectivity | <1.7% (MgF2) | <0.5% (BBAR) | ~4% (uncoated) | ~4% (uncoated) |
| temperature coefficient* a/R0 (typ.) | 15×10-6/K | 3×10-6/K | 3×10-6/K | 3×10-6/K |
| tilt sensitivity* | max. angle of incidence typ. 1° | |||
* Definition Fresnel rhombs are quite sensitive to tilt and show a qualitative difference compared to birefringent retarders. The angular coefficient is not meaningful for Fresnel rhombs.
| version | λ/2, plate mount | λ/2, rotation mount | λ/4 | |
| free aperture | [mm] | 9.5 | 9.5 | 9.5 |
| mount diameter | [mm] | 50 | 59 | 48 |
| mount length | [mm] | 65 | 76 | 40.3 |
| connection | [mm] | 25 | 14 (post mount M8) | 25 |
| Art. No. 215-450 nm | RFR 1.215 | RFR 2.215 | RFV 215 | |
| Art. No. 400-700 nm | RFR 1.400 | RFR 2.400 | RFV 400 | |
| Art. No. 500-1300 nm | RFR 1.500 | RFR 2.500 | RFV 500 | |
| Art. No. 650-1700 nm | RFR 1.650 | RFR 2.650 | RFV 650 |
For up-to-date prices, please refer to the current price list or request a quote.
For up-to-date prices, please refer to the current price list or request a quote.
For up-to-date prices, please refer to the current price list or request a quote.
| special antireflection coating | on request |
| rhombs made from ZnSe for the mid IR range | on request |
| unmounted rhombs | on request |
.png)
