Implementing Your Own Light Source into the Calibrator
Script with Spectrum Pattern file
Introduction
Our Light Calibrator is a regular radiometer/photometer instrument that measures light intensity of monochromatic light.
However, it can also be used to accurately measure broadband (not monochromatic) light sources as long as the power spectrum of the source, $S(\lambda)$, is known.
You can enter just a single number given by the expression
$$
\frac{ \int^{1100\;nm}_{200\;nm}S(\lambda)R(\lambda)d\lambda }{ \int^{1100\; nm}_{200\; nm}S(\lambda)d\lambda},
$$
where $R(\lambda)$ is the calibrators detector responsivity curve and the integration limits are determined by the range of the spectral sensitivity of a silicon based detector.
A user can program the Light Calibrator with up to 6 such numbers. That means, that the instrument can accurately measure light output of up to six predefined broadband light sources like LEDs, arc lamps and similar.
The script described in the following will help you determine the number that needs to be computed first and than introduced to the instrument.
Equipment Preparation: Ensure that the calibrator is properly connected to your computer via a USB cable. The program communicates with the device through a serial port, so it is crucial to ensure that the port is correctly configured and free from other connections.
Launching the Program: Open the program in the Octave or MATLAB environment, and then run the script. The program will automatically initiate communication with the calibrator.
Downloading Mother Calibration: Initially, the program sends commands to the calibrator to retrieve the calibration settings stored within it. These data are vital as they form the basis for calculating the coefficient for the new light source.
Entering New Light Source Data: The program requires the input of the spectrum data of the new light source, which is essential for calculating the new calibration coefficient. These data should be loaded in accordance with the “spectrum_pattern.dat” standard spectrum file.
Calculating the Coefficient: After all necessary data have been entered, the program proceeds with interpolation and calculations, resulting in the calibration coefficient for the new light source. This coefficient is calculated based on the integrated spectral data and is used to adjust the calibrator’s response.
Updating the Calibrator: The final step is to manually enter the calculated coefficient into the calibrator through its user interface.
❗️ Remember to change the 8th line in code depending on the system and port:
serial_port = 'COM*'; for Windowsserial_port = '/dev/ttyUSB*'; for Linux
where * is digit. By default, it is COM3 for Windows and ttyUSB0 for Linux.
