Radiated optical energy, as measured by Avantes spectrometers, can be quantified as a radiant flux, a measure in energy per second (Watt) radiated from a source. The radiated optical energy can be correlated with human vision (photometry) as defined in the CIE to obtain a spectral luminous efficiency function to characterize the vision of an average human observer.
Both radiometric and photometric quantities can be measured with an irradiance calibrated Avantes spectrometer system. Radiometric quantities are radiant energy (in Joule), Radiant power or flux (in Watt) or irradiance (Watt per cm²). Related photometric quantities are luminous flux (lumen) or illuminance (lux or lumen per m²).
With the AvaSoft Irradiance Application it is possible to calculate the above parameters from the measured spectral distribution. A calibrated light source AvaLight-HAL-CAL or AvaLight-DH-CAL with known energy output (in µWatt/cm2/nm) is used as a reference. This calibration can be performed, saved and loaded by the end user.
An other option is to have your Avantes spectrometer system calibrated in our irradiance calibration lab, so there is no need to have an additional calibrated light source. The calibration can be loaded into the AvaSoft-IRRAD software.
Color of light parameters can be expressed by the chromaticity coordinated x, y and z. These chromaticity coordinates are obtained by taking the ratios of the tristimulus values (X, Y and Z) to their sum. The tristimulus values X, Y and Z and the spectral irradiance are computed in a wavelength range from 380 nm to 780 nm, using a 1 nm interval. These parameters, as well as the coordinates u and v and the color temperature of an external light source can be calculated and displayed in real-time.
New in AvaSoft-IRRAD 7.4 is that the CRI color rendering index of al light source is calculated as well. The color rendering index of a light source with a color temperature <5000K is a measure of how close a light source matches a perfect black body radiant.
New in AvaSoft 7.4 is also that there is a setting for auto-adjust the integration time, so a large dynamic range can be achieved for applications that have both very high light level and very low light level, such as solar measurements.
The same experimental set up (spectrometer with fiber optics and cosine corrector or integrated sphere) is used to calculate the intensity of the light to be measured.
The calculated output can be displayed and saved in two ways:
* -In the Irradiance Chart the data can be displayed as spectral irradiance in µWatt/nm versus wavelength, like in the screendump above. Further, the following output parameters can be displayed: radiometric quantities µWatt/cm2, µJoule/cm2, µWatt or µJoule, photometric quantities Lux or Lumen, color coordinates X, Y, Z, x, y, z, u, v, color rendering index and color temperature, and number of photons µMol/s/m2, µMol/m2, µMol/s and µMol. In addition raw data in Scope mode is displayed as well as the X-Y Chromaticity diagram, including parameters, specially useful for LED measurements, such as: Dominant Wavelength, Purity, Central Wavelength, Peak Wavelength, Centroļd, etc.
* -In Time Measurement mode, up to 8 functions can be displayed simultaneously against time. For each function, a different radiometric, photometric, photon or color coordinate output parameter and/or wavelength range may be selected, as well as a different spectrometer channel.