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Looking For a Custom Optical Solution? Enquire

Custom Lenses

custom lenses, infrared lenses, aspheric lenses, achromatic lenses, optical lensKnight Optical is experienced in providing bespoke lenses to our customers. From plano-convex to cylindrical and aspheric lenses, Knight Optical provides a superior service from enquiry through to delivery.

We are able to provide you with lenses designed for use in UV up to IR applications, using substrates such as UV fused silica and Schott glass to crystalline materials such as germanium and silicon. Browse our infrared materials for more information on the different available infrared crystal substrates.

Below are our typical manufacturing capabilities for visible applications using Schott (or equivalent) material however we are always expanding our capabilities so please do not hesitate to contact us. Due to different manufacturing/growing processes for more specialist UV and IR substrates, the manufacturing capabilities can vary.


Diameter (mm)

Focal length (mm)

Form Error (fringes)

Centration (arc minutes)



3 to 200+

3 to 1000+

< 0.5

< 3

< 60/40


3 to 200+

3 to 1000+

< 0.5

< 3

< 60/40


3 to 200+

3 to 1000+

< 0.5

< 3

< 60/40

Ball and half-ball

0.15 to 30+

< Surface roughness (Ra) < 0.020µm


5 to 1500+

3 to 1500+

All custom lenses are tested in our metrology laboratory and then 100% visually inspected by our QA department to ensure they meet your specific requirements.

Contact our technical sales team to find out how Knight Optical can help you with your custom order.

Browse the shortcuts below to find out more information about the different lens types that Knight Optical can help with:

Additional Information

  • Knight Optical has been supplying infrared lenses for a variety of applications. From large germanium aspheric lenses with diameters above 200mm to zinc sulphide ball lenses with diameters below 5mm.
  • There are different optical distortions that can be introduced when using lenses, including spherical and chromatic aberration.
  • Spherical aberration occurs when the incident beam focusses at different points after exiting the lens, and therefore a blur can be created within the image. A spherical lens can be sensitive to the angle of incidence of the light beam.
  • This spherical aberration can be corrected by either using multiple lenses within a system, or by using an aspheric lens.
  • Chromatic aberration is when different wavelengths of light focus at different points due to dispersion. This occurs as the refractive index of the material is wavelength dependent.
  • Achromatic lenses are manufactured by cementing a high-index lens (flint) to a strongly positive low-index lens (crown) which can then correct for two colours e.g. red and blue. The two lenses used are calculated to match the focal length for these two chosen wavelengths.
  • An apochromatic triplet lens can be used to correct chromatic aberration for three colours.


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, including broadband coatings, to optimise the transmission at certain wavelengths or across a range.
  • Diamond-like carbon (DLC) coating to increase the durability of a surface.
  • Hydrophobic coating to repel water from a surface.
  • More specialist coatings such as ITO, anti-fog and oleophobic.

Quality Assurance

  • Radius of curvature and the irregularity of spherical surfaces are checked on our Zygo Verifire interferometer, which also gives us the capabilities to test transmitted wavefront distortion.
  • Our Trioptics OptiSpheric and OptiCentric are used to test the focal length and centering error respectively.
  • Knight Optical can check optical coatings 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 coatings 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 for lenses used in laser applications.


Our 2022/2023 Catalogue

Inside Knight Optical’s catalogue you’ll find details of the industries we serve as well as the many other services we can offer. It also showcases hundreds of our most popular products, supported by useful technical information, to help you choose the right part for your application.
Click below to view our digital catalogue now.

view our catalogue