Superachromatic Retarders

Superachromatic retarders consist of a combination of three achromatic double plates. The residual deviation of the retardation is minimized by optimization of the relative axis orientation between the plates. Therefore, superachromatic retarders can be used over an even broader spectral range.

The orientation of the effective principal axes is not constant for this design but shows a slight variation over the spectrum similar to that of the retardation.

The plates are cemented and the outer surfaces are antireflection coated with a MgF ₂ single layer.

DThe retarders a provided with a cylindrical holder.

We offer superachromatic retarders optimized for the ranges 310-1100 nm and 600-2700 nm, respectively. For this type the difference of the specifications for half wave plates and quarter wave plates is not simply given by a factor of two. Therefore, the values are given separately for both types in the following.

• General specifications
• Range 1 310-1100 nm
• Range 2 600-2700 nm
• Custom versions and accessories

version	310-1100 nm, λ/2	310-1100 nm, λ/4	600-2700 nm, λ/2	600-2700 nm, λ/4
material	quartz and MgF 2	quartz and MgF 2	quartz and MgF 2	quartz and MgF 2
wavefront distortion	< λ/10	< λ/10	< λ/10	< λ/10
prismatic deviation	<1'	<1'	<1'	<1'
marked direction	slow axis	slow axis	slow axis	slow axis
tolerance of the path difference	±3 nm	±3 nm	±3 nm	±3 nm
reflectivity	<2,5%	<2,5%	<2,5%	<2,5%
connection of the plates	cemented with cover plates	cemented with cover plates	cemented without cover plates	cemented without cover plates
deviation of retardation	± 1,3%	± 4%	± 0,04%	± 0,25%
variation of the axis direction	± 2°	± 1,5°	± 0,2°	± 0,1°
temperature coefficient * a (typ.)	<0,1 nm/K	<0,05 nm/K	<0,02 nm/K	<0,04 nm/K
angular coefficient * b (typ.) *	1 nm/deg²	0,5 nm/deg²	3 nm/deg²	2 nm/deg²

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	15	15
Art. No., λ/2		RSU 1.2.10	RSU 1.2.15	RSU 1.2.20	RSU 1.2.25
Art. No., λ/4		RSU 1.4.10	RSU 1.4.15	RSU 1.4.20	RSU 1.4.2

* Definition The pattern of the retardation change on tilt is rotated by 45° for these retarders.

λ/2 Wavelength variation of the retardation R and the axis direction Ψ

λ/4 Wavelength variation of the retardation R and the axis direction Ψ

Prices

λ/2 superachromatic waveplates with cover plates

order no.	1 piece in €	2-5 piece in €	6-10 piece in €
RSU 1.2.10	2164.-	1968.-	1744.-
RSU 1.2.15	3429.-	3073.-	2667.-
order no.	1 piece in €	2 piece in €	3-5 piece in €
RSU 1.2.20	6237.-	5504.-	4917.-
RSU 1.2.25	7991.-	7051.-	6299.-

λ/4 superachromatic waveplates with cover plates

order no.	1 piece in €	2-5 piece in €	6-10 piece in €
RSU 1.4.10	2164.-	1968.-	1744.-
RSU 1.4.15	3429.-	3073.-	2667.-
order no.	1 piece in €	2 piece in €	3-5 piece in €
RSU 1.4.20	6237.-	5504.-	4917.-
RSU 1.4.25	7991.-	7051.-	6299.-

λ/2 Wavelength variation of the retardation R and the axis direction Ψ

λ/4 Wavelength variation of the retardation R and the axis direction Ψ

Prices

λ/2 superachromatic waveplates without cover plates

order no.	1 piece in €	2-5 piece in €	6-10 piece in €
RSU 2.2.10	2054.-	1872.-	1664.-
RSU 2.2.15	3302.-	2960.-	2569.-
order no.	1 piece in €	2 piece in €	3-5 piece in €
RSU 2.2.20	6074.-	5359.-	4788.-
RSU 2.2.25	7761.-	6848.-	6118.-

λ/4 superachromatic waveplates without cover plates

order no.	1 piece in €	2-5 piece in €	6-10 piece in €
RSU 2.4.10	2054.-	1872.-	1664.-
RSU 2.4.15	3302.-	2960.-	2569.-
order no.	1 piece in €	2 piece in €	3-5 piece in €
RSU 2.4.20	6074.-	5359.-	4788.-
RSU 2.4.25	7761.-	6848.-	6118.-

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