This filter comes from Thorlabs, expensive, but I truly doubt you can find similar quality in China.
I went on Sunday to one garden centre and I bought these 4 beauties.
I applied Blue and Red light
And the results are amazing!
Switching the white or red light with the previous filter would have rendered the fluorometer useless; but with the 700nm filter the only light passing through is the plant's fluorescence. The monochrome images are simply mesmerising. The false color images give us a better view of intensity distribution.
The next chapter is to calibrate the camera with the spectralon panel, add the Arduino to control the actinic pulses, add the measuring light (ML) to calculate Mo and calibrate the thermal camera (see one thermal image below).