What does the diffuser look like?

Drawing with dimensions of diffuser BAT 5

The diffuser’s distance to fibre distance is matched to the fibre’s N.A. There is a slight slope in the diffuser’s surface to drain the water through a drainage hole. An 'o'-ring gives additional protection against rain.

The diffuser can be made in almost any size. Here is a slightly smaller model:

Drawing with dimensions of diffuser BAT 6

Characteristics of the smaller and bigger diffuser are almost the same.

Diffuser characteristics

  1. Good Cosine response with known correction factors.
  2. Reasonably good random polarised transmission independent to temperature changes.
  3. Transmission insesitive to geometrical changes (~0.25 mm)
  4. Cosine response insensitive to geometrical changes
  5. Solid weatherproof design
  6. Negligibly small azimuth errors
  7. No spikes in signal at higher wavelengths

Info, questions and remarks:


Emeritus Researcher – Atmospheric Radiation