Knight Optical can provide a variety of optical components that can control the polarisation state of incident light, either by filtering all but one state, or modifying the current state of polarisation. Typical polarisation components include:
- Linear polarisers.
- Circular polarisers.
- Waveplates including quarter and half waveplates, manufactured from crystalline materials such quartz and magnesium fluoride depending on the operating wavelength.
- Achromatic waveplates/retarders are manufactured using two waveplates, often quartz and magnesium fluoride, which allows the waveplate to be used over a broader waveband, an AR coating can be applied to optimise the performance over a certain range.
- Fresnel rhomb retarders.
- Polarising beamsplitters which will transmit P polarisation and reflect S polarisation.
- Polarising prisms such as Rochon, Glan-Taylor, and Wollaston, which utilise the birefringent property of certain crystalline materials including calcite, quartz, and magnesium fluoride.
Knight Optical stock a vast range of linear and circular polariser films, which can be cut to size for a fast turnaround. This includes our HNCP37 equivalent circular polariser which comes in both left- and right-handed types. For linear polarisers, we hold a vast stock of equivalent material for the original 3M polarisers (HN22, HN32, HN38, HN38S, HN42 and HN42HE types). Information sheets for these can be found here.
Below are our typical manufacturing capabilities for waveplates:
12.5mm to 50mm+
¼ wave or ½ wave
257nm to 1650nm
< 1/100 waves
Mounted or unmounted
Browse the categories below for further information on these different polarising optics:
- Linear polarisers work by filtering out, either via absorption or reflection, the undesired polarisation states and only transmitting one linearly polarised beam across a single plane.
- Circular polarisers are manufactured from a linear polariser and a quarter waveplate and they work together to modify unpolarised light into two rotating linearly polarised beams that are perpendicular to each other. The direction of this rotation denotes whether the polariser is a left- or right-handed polariser.
- Waveplates, or retarders, are manufactured from birefringent materials which modify the polarisation state of light that passes through it. The most common types are quarter- and half-waveplates. The material, thickness and wavelength of light used are all factors into the waveplate performance.
- A birefringent material has two distinct refractive indices. The polarisation modification occurs when an unpolarised light beam enters the input surface of the material it splits into two polarised beams—the ordinary (o) and extraordinary (e) ray.
- Crystalline materials such as calcite and quartz are commonly used in waveplates and polarising prisms due the birefringence they exhibit.
- A quarter waveplate modifies linearly polarised light to circularly polarised, and vice versa.
- A half waveplate can rotate the plane of the linearly polarised light.
Knight Optical can also apply a wide range of coatings to your optical windows to enhance their transmission or increase their durability:
- Antireflective (AR) coatings can be applied to enhance the optics performance, this can be especially critical with waveplates.
- The flatness and irregularity of our optical polarisation optics are tested on our Zygo Verifire XPZ interferometer when required.
- We check the parallelism on our Trioptics PrismMaster which is accurate to 3 arc seconds.
- Transmission and reflection scans are conducted on our Agilent Cary 7000 Spectrophotometer which can perform spectral scans at multiple angles of incidence and different polarisations.
- We can also test infrared optical components on our Agilent Cary 660 FTIR spectrometer.
- All optics are 100% visually inspected before packaging, our staff are trained to ISO 10110 and MIL-0-13830A, and can check down to 10/5 scratch/dig which is especially critical in laser applications.