An integrating sphere is an optical component composed of a hollow spherical cavity that has two small windows orientated at 90◦ one with respect to the other. The first window corresponds to the input port whereas the other is the output port where a detector is located. For commercial devices, the interior of the sphere is covered with a diffuse reflective coating. When light enters to the sphere, it is reflected equally in all directions due to scattering. As a result, an integrating sphere is a device that can be used to measure optical power, while the spatial information of the input beam is destroyed (i.e. beam shape and entrance angle).
In the figures is shown the 3D printed integrating sphere developed. The hollow sphere is printed using white PLA. In our design the output window allows to use any of the following detectors: webcam or Raspberry Pi camera.
A program written in Python is used to calibrate the integrating sphere with respect to a known reference and also to perform further power measurements. For additional information go to http://arxiv.org/pdf/1606.09563.pdf