All AvaSpec spectrometers come standard with a wavelength calibration and coefficients, to calculate wavelength from pixel number. This information is installed on-board, on the AvaSpec’s EEPROM.
Under normal conditions the wavelength calibration does not need to be redone, since the spectrometers have no moving elements inside. If a wavelength shift is measured versus the original wavelength calibration, the spectrometer can be recalibrated by the end-user, using the Avalight-CAL using the auto-calibration software routine in AvaSoft-Full.
As an option the spectrometer can also be returned to Avantes for recalibration, (Spectral-cal-service). Before returning the spectrometer an RMA authorization number needs to be obtained.
Most detectors of the AvaSpec spectro-meters have a good linear behavior in their detector response, which means that there is a better than 95% correlation between raw signal in A/D counts and the light intensity at the spectrometer entrance.
However for some applications, which require a wide dynamic range, such as highly absorbing substances or low light level applications, combined with a need for high accuracy, a non-linearity calibration of the detector is recommended. This NL-calibration is performed on the detector array and the output signal is linearized to better than 99%. A complete calibration report and the calculated NL calibration coefficients are delivered with the spectrometer. For irradiance calibrations the NL-calibration is automatically included.
Applications that use spectrometers to measure the light energy of radiant sour-ces require an irradiance-calibrated spectrometer. For all AvaSpec spectrometers both irradiance and radiance NIST traceable calibrations can be offered. Irradiance calibrations (µW/cm2) are normally performed on a system with a fiber-optic cable and a cosine corrector or integrating sphere. Radiance calibrations (µW/cm2/sr) can be performed on a spectrometer and a bare fiber or fiber with collimating lens looking at a diffuse illuminated surface.
The (ir)radiance calibrations can be performed over 3 different wavelength ranges, UV (200-400 nm), VIS (360-1100 nm) and NIR (1100-2500 nm). All systems are calibrated against a NIST traceable irradiance calibration standard and come with a complete report and calibration files, which are stored on the EEPROM of the spectrometer and can be loaded directly into the AvaSoft-IRRAD software module to obtain irradiance parametric measurements.
More information on irradiance can be found in the software section (AvaSoft-IRRAD) and the section Applications - Irradiance Measurements.
As an alternative to Avantes irradiance calibration services, irradiance calibrated light sources, such as AvaLight-DHS-CAL and AvaLight-HAL-CAL are available to perform your own irradiance calibration.