We provide regular transmittance measurements from 200 nm to 3000 nm, at either selected wavelengths or by using a scanning technique at regular intervals. Wavelength intervals are typically 5 nm and can be as low as 0.05 nm. Small wavelength interval scans are most useful when measuring wavelength standards that have narrow absorption bands. The spectral bandwidth used for wavelengths up to 800 nm is chosen by the customer and can be up to 5.0 nm. Above 800 nm, the bandwidth usually varies with wavelength up to a maximum of 20.0 nm. Typical measurement uncertainty for a 90% transmitting filter in the visible part of the spectrum is ± 0.2%. Uncertainties for other transmittance values or wavelengths depend on the filter characteristics.
Solar integrated values of transmittance can be calculated using Parry Moon air mass 0, 1 and 2, or Makarova air mass 0 solar data.
For narrow bandpass filters, we can provide calibrations of the wavelength of the transmittance / absorption peak, as well as other data such as the half height bandwidth, centre wavelength and wavelength of centre of gravity of peak.
Our research and measurement solutions support innovation and product development. We work with companies to deliver business advantage and commercial success. Contact our Customer Services team on +44 20 8943 7070