Calibration of spectrophotometers and accessories

GL Optic offers a spectrophotometer calibration service with integrated sphere approaches or luminance sensors

Calibration is done in different stages:

– Wavelength calibration

The wavelength calibration of matrix spectroradiometers is performed using a low-pressure Hg-Ar lamp producing mercury and argon spectral lines from 253 to 1700 nm. It is dedicated to the determination of the wavelength represented by each pixel of the matrix detector used in the spectroradiometer. An appropriate software tool provided with the media can determine the polynomial used to express the relationship between pixel position and spectral wavelength

– Spurious light calibration

The calibration procedure is based on a series of spectral measurements in the wavelength range required by a spectroradiometer. A dedicated software then creates the correction table which becomes input data (a correction file) for the stray light reduction algorithm used by the GL Optic spectroradiometer firmware. The Stray Light Reduction software can reduce stray light up to 2 * 10E-4 for GL Spectis 5.0 Touch.

– Calibration of detector linearity

It consists of an automatic optical bench 7 m long, fully programmable and with dedicated software. The length of the optical bench combined with high positioning accuracy (up to 10 μm) allows simple use of the inverse square law in a wide dynamic range, ensuring significantly lower error compared to other methods used for linearity calibration. The optical bench can cover a dynamic range of 1:1000 with a single pass and more than 1:1000000 with multiple passes. It can be used for linearity verification and calibration of spectroradiometers, photometers and radiometers.

– Absolute spectral illumination calibration and illuminance calibration

The multiple reference standards and light sources are mounted on the automatic changer combined with the same optical bench and are used to perform the absolute spectral irradiance and illuminance calibrations. Extended spectral calibration in the UV 200 nm range over the entire VIS range up to NIR 1050 nm is performed using deuterium and halogen standards. This facility is capable of performing absolute calibration of photometers and spectroradiometers.