Hamamatsu S780-66BQ photodiodes. TO-8 glass window package. Wide spectral sensitivity. I have not been able to find a datasheet for these photodiodes, but have found a few journal articles that use S780 photodiodes for optical intensity measurements and will provide references to those upon request. These may be useful in Li-Fi applications for sensitive light intensity and power measurements. I doubt they have the temporal response to be useful for demodulation, but have not measured this response. After reviewing the information I did find, they seem to be most similar to the Hamamatsu S1226 and S1336. Bench testing yields over 500 microamps at 460 millivolts when exposed to fluorescent room lighting. Consistent repeatability.