Circular Linear Wedge Filter Wheel

Torr Scientific make Neutral Density Filter Wheels in a range of sizes from 50mm f  to 100mm  f, and with differing optical densities 0-1, 0-2, and 0-3.
These filters are useful as beam splitters and for applications requiring variable light attenuation in a continuous analogue mode, such as in spectro-photometers, laser measuring systems etc.
We use Laser quality Spectrosil for UV / VIS / NIR applications, and for its thermal stability.

All filter wheels are manufactured to tight tolerances especially parallelism to minimise beam movement with rotation (see below)

• Material:  Laser quality quartz - Spectrosil

• Trans      > 90% for 190nm < l < 2500nm

• Optical Density   Linearity: +/- 6% (with angle)

• Coated Sector:    300⁰

• Parallelism :        20 arc seconds*
  (* 20 arc sec is equivalent to 80 mm movement at 1 m – 3 arc min sometimes specified on low cost wheels is equivalent to 0.7 mm @ 1m)

• Surface Quality:   80-50 scratch / dig

• Coating:              PVD metallic alloy*
  (*optimised for spectral neutrality over a  wide range)

• Dimensional Tolerance: < +/-0.2mm

AND very competitively priced !

Each filter wheel is supplied with a test certificate  - typical data for a non-standard density of 2.25 is shown above, and stays well within the specified linearity tolerance of +/- 6%
Specially designed items can also be accommodated on request.

Product Designation 

fA

fB

r₁

r₂

t

fC*

D*

LFW 50

50

15

10

23

4

4

17

LFW75

75

15

10

35

4

4

30

LFW100

100

15

10

48

4

4

42