Achromatic Retarders
Achromatic retarders can be regarded as zero order double plates where the two plates are manufactured from different materials (quartz and MgF22 ). By exploiting the difference of dispersion of the birefringence one achieves an almost constant phase shift over a broader spectral range.
The retarders are available either cemented between cover plates or in a cementless version with air gap. The cemented version is the more economical one and exhibits slightly lower reflection losses. The version with air gap excels in a high damage threshold and low material dispersion.
The retarders are delivered in a cylindrical mount.
We manufacture achromatic retarders for six standard spectral ranges specified below. The diagrams of the path difference versus wavelength shows the values for the half wave plates. For quarter wave plates the retardation has half the value at any wavelength.
The retarders covering short wavelength ranges require one or both of the crystal plates to be manufactured as double plate leading to a total number of three or four plates, respectively. For the cemented version a significant reflection loss only occurs at the two outer surfaces. For the version with air gap reflection losses have to be considered on both surfaces of each plate, namely 4-8 surfaces.
Achromatic retarders with air gap are particularly suited for ultra-short pulsed lasers. For this reason their group delay dispersion (GDD) is specified for a representative wavelength in the table. The dispersion for the cemented version is significantly larger due to the cover plates .
| material | quartz and MgF2 |
| wavefront distortion | <λ/10 |
| prismatic deviation | <2'' (air gap), <1' (gekittet) |
| marked direction | fast axis |
| tolerance of the path difference | ±3 nm |
Standard dimensions
| Format | 10 mm | 15 mm | 20 mm | 25 mm | |
| free aperture | [mm] | 9,5 | 14,5 | 19,5 | 24,5 |
| mount diameter | [mm] | 25 | 25 | 30 | 40 |
| mount length | [mm] | 10 | 10 | 10 | 15 |
| Art. Nr.:, all ranges λ/2 | RAC X.2.10 | RAC X.2.15 | RAC X.2.20 | RAC X.2.25 | |
| Art. Nr.:, all ranges λ/4 | RAC X.4.10 | RAC X.4.15 | RAC X.4.20 | RAC X.4.25 | Art. Nr.:, all ranges λ/2 air gap | RAC X.2.10 L | RAC X.2.15 L | RAC X.2.20 L | RAC X.2.25 L |
| Art. Nr.:, all ranges λ/4 air gap | RAC X.4.10 L | RAC X.4.15 L | RAC X.4.20 L | RAC X.4.25 L |
| spectral range 1 | 180-300 nm |
| deviation of retardation | ± 8,5% |
| number of plates | 4 |
| reflectivity | quartz: <2% MgF2: <3% |
| temperature coefficient* α(typ.) | λ/2: 2∙10-3nm/K λ/4:1∙10-3 nm/K |
| angular coefficient* ß (typ.) | 2,5 nm/deg² |
| GDD (λ=266 nm) | 500 fs² |
λ/2 version with air gap
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 1.2.10L | 925.- | 859.- | 784.- |
| RAC 1.2.15L | 1543.- | 1416.- | 1272.- |
| RAC 1.2.20L | 2536.- | 2311.- | 2053.- |
| RAC 1.2.25L | 3841.- | 3461.- | 3028.- |
λ/4 version with air gap
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 1.4.10L | 925.- | 859.- | 784.- |
| RAC 1.4.15L | 1543.- | 1416.- | 1272.- |
| RAC 1.4.20L | 2536.- | 2311.- | 2053.- |
| RAC 1.4.25L | 3841.- | 3461.- | 3028.- |
| spectral range 2 | 300-470 nm |
| deviation of retardation | ± 5% |
| number of plates | λ/2: 3 λ/4: 4 |
| reflectivity | <0,5% |
| temperature coefficient* α(typ.) | λ/2: 0,05 nm/K λ/4:0,025 nm/K |
| angular coefficient* ß (typ.) | λ/2: 1,5 nm/deg² λ/4:2,4 nm/deg² |
| GDD (λ=400 nm) | λ/2: 94 fs² λ/4: 250 fs² |
λ/2 version cemented with cover plates
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 2.2.10 | 786.- | 730.- | 666.- |
| RAC 2.2.15 | 1293.- | 1187.- | 1066.- |
| RAC 2.2.20 | 2099.- | 1912.- | 1699.- |
| RAC 2.2.25 | 3278.- | 2954.- | 2584.- |
λ/4 version cemented with cover plates
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 2.4.10 | 921.- | 855.- | 780.- |
| RAC 2.4.15 | 1537.- | 1411.- | 1267.- |
| RAC 2.4.20 | 2528.- | 2304.- | 2047.- |
| RAC 2.4.25 | 3921.- | 3534.- | 3091.- |
λ/2 version with air gap
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 2.2.10L | 888.- | 824.- | 752.- |
| RAC 2.2.15L | 1483.- | 1361.- | 1222.- |
| RAC 2.2.20L | 2430.- | 2214.- | 1967.- |
| RAC 2.2.25L | 3585.- | 3231.- | 2827.- |
λ/4 version with air gap
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 2.4.10L | 1023.- | 950.- | 866.- |
| RAC 2.4.15L | 1727.- | 1586.- | 1424.- |
| RAC 2.4.20L | 2860.- | 2605.- | 2315.- |
| RAC 2.4.25L | 4228.- | 3811.- | 3334.- |
| spectral range 3 | 460-680 nm |
| deviation of retardation | ± 3% |
| number of plates | 2 |
| reflectivity | <0,5% |
| temperature coefficient* α(typ.) | λ/2: 0,2 nm/K λ/4:0,1 nm/K |
| angular coefficient* ß (typ.) | λ/2: 0,8 nm/deg² λ/4:0,4 nm/deg² |
| GDD (λ=515 nm) | λ/2: 62 fs² λ/4: 31 fs² |
λ/2 version cemented with cover plates
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 3.2.10 | 592.- | 550.- | 501.- |
| RAC 3.2.15 | 951.- | 873.- | 784.- |
| RAC 3.2.20 | 1541.- | 1404.- | 1248.- |
| RAC 3.2.25 | 2350.- | 2118.- | 1853.- |
λ/4 version cemented with cover plates
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 3.4.10 | 592.- | 550.- | 501.- |
| RAC 3.4.15 | 951.- | 873.- | 784.- |
| RAC 3.4.20 | 1541.- | 1404.- | 1248.- |
| RAC 3.4.25 | 2350.- | 2118.- | 1853.- |
λ/2 version with air gap
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 3.2.10L | 715.- | 664.- | 606.- |
| RAC 3.2.15L | 1166.- | 1071.- | 961.- |
| RAC 3.2.20L | 1874.- | 1708.- | 1517.- |
| RAC 3.2.25L | 2681.- | 2416.- | 2114.- |
λ/4 version with air gap
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 3.4.10L | 715.- | 664.- | 606.- |
| RAC 3.4.15L | 1166.- | 1071.- | 961.- |
| RAC 3.4.20L | 1874.- | 1708.- | 1517.- |
| RAC 3.4.25L | 2681.- | 2416.- | 2114.- |
| spectral range 4 | 500-900 nm |
| deviation of retardation | ± 6 % |
| number of plates | 2 |
| reflectivity | <0,5% |
| temperature coefficient* α(typ.) | λ/2: 0,3 nm/K λ/4: 0,15nm/K |
| angular coefficient* ß (typ.) | λ/2: 1,1 nm/deg² λ/4:0,6 nm/deg² |
| GDD (λ=800 nm) | λ/2: 50 fs² λ/4: 25 fs² |
λ/2 version cemented with cover plates
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 4.2.10 | 592.- | 550.- | 501.- |
| RAC 4.2.15 | 951.- | 873.- | 784.- |
| RAC 4.2.20 | 1541.- | 1404.- | 1248.- |
| RAC 4.2.25 | 2350.- | 2118.- | 1853.- |
λ/4 version cemented with cover plates
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 4.4.10 | 592.- | 550.- | 501.- |
| RAC 4.4.15 | 951.- | 873.- | 784.- |
| RAC 4.4.20 | 1541.- | 1404.- | 1248.- |
| RAC 4.4.25 | 2350.- | 2118.- | 1853.- |
λ/2 version with air gap
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 4.2.10L | 715.- | 664.- | 606.- |
| RAC 4.2.15L | 1166.- | 1071.- | 961.- |
| RAC 4.2.20L | 1874.- | 1708.- | 1517.- |
| RAC 4.2.25L | 2681.- | 2416.- | 2114.- |
λ/4 version with air gap
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 4.4.10L | 715.- | 664.- | 606.- |
| RAC 4.4.15L | 1166.- | 1071.- | 961.- |
| RAC 4.4.20L | 1874.- | 1708.- | 1517.- |
| RAC 4.4.25L | 2681.- | 2416.- | 2114.- |
| spectral range 5 | 600-1200 nm |
| deviation of retardation | ± 5% |
| number of plates | 2 |
| reflectivity | <0,8% |
| temperature coefficient* α(typ.) | λ/2: 0,5 nm/K λ/4: 0,25nm/K |
| angular coefficient* ß (typ.) | λ/2: 1,6 nm/deg² λ/4:0,8 nm/deg² |
| GDD (λ=800 nm) | λ/2: 75 fs² λ/4: 37 fs² |
λ/2 version cemented with cover plates
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 5.2.10 | 592.- | 550.- | 501.- |
| RAC 5.2.15 | 951.- | 873.- | 784.- |
| RAC 5.2.20 | 1541.- | 1404.- | 1248.- |
| RAC 5.2.25 | 2350.- | 2118.- | 1853.- |
λ/4 version cemented with cover plates
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 5.4.10 | 592.- | 550.- | 501.- |
| RAC 5.4.15 | 951.- | 873.- | 784.- |
| RAC 5.4.20 | 1541.- | 1404.- | 1248.- |
| RAC 5.4.25 | 2350.- | 2118.- | 1853.- |
λ/2 version with air gap
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 5.2.10L | 715.- | 664.- | 606.- |
| RAC 5.2.15L | 1166.- | 1071.- | 961.- |
| RAC 5.2.20L | 1874.- | 1708.- | 1517.- |
| RAC 5.2.25L | 2681.- | 2416.- | 2114.- |
λ/4 version with air gap
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 5.4.10L | 715.- | 664.- | 606.- |
| RAC 5.4.15L | 1166.- | 1071.- | 961.- |
| RAC 5.4.20L | 1874.- | 1708.- | 1517.- |
| RAC 5.4.25L | 2681.- | 2416.- | 2114.- |
| spectral range 6 | 700-2500 nm |
| deviation of retardation | ± 4% |
| number of plates | 2 |
| reflectivity | <2% |
| temperature coefficient* α(typ.) | λ/2: 0,6 nm/K λ/4: 0,3nm/K |
| angular coefficient* ß (typ.) | λ/2: 1,9 nm/deg² λ/4:0,9 nm/deg² |
| GDD (λ=1550 nm) | λ/2: -59 fs² λ/4: -29 fs² |
λ/2 version cemented with cover plates
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 6.2.10 | 592.- | 550.- | 501.- |
| RAC 6.2.15 | 951.- | 873.- | 784.- |
| RAC 6.2.20 | 1541.- | 1404.- | 1248.- |
| RAC 6.2.25 | 2350.- | 2118.- | 1853.- |
λ/4 version cemented with cover plates
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 6.4.10 | 592.- | 550.- | 501.- |
| RAC 6.4.15 | 951.- | 873.- | 784.- |
| RAC 6.4.20 | 1541.- | 1404.- | 1248.- |
| RAC 6.4.25 | 2350.- | 2118.- | 1853.- |
λ/2 version with air gap
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 6.2.10L | 715.- | 664.- | 606.- |
| RAC 6.2.15L | 1166.- | 1071.- | 961.- |
| RAC 6.2.20L | 1874.- | 1708.- | 1517.- |
| RAC 6.2.25L | 2681.- | 2416.- | 2114.- |
λ/4 version with air gap
| order no. | 1 piece in € | 2-5 piece in € | 6-10 piece in € |
|---|---|---|---|
| RAC 6.4.10L | 715.- | 664.- | 606.- |
| RAC 6.4.15L | 1166.- | 1071.- | 961.- |
| RAC 6.4.20L | 1874.- | 1708.- | 1517.- |
| RAC 6.4.25L | 2681.- | 2416.- | 2114.- |
| adaptor for mount diameters 30mm and 40 mm | adaptor ring mount |
| connection with Thorlabs SM1 or SM2 thread | on request |
| other sizes (up to 100 mm) | on request |
| unmounted plates | on request |
| other spectral ranges | on request |
