Photocathodes

 

The photocathode is the entrance of the image intensifier. This is where the incoming photons are converted to electrons. The quantum efficiency of the photocathode material specifies how efficient this conversion is for each wavelength.

 
 

Second generation image intensifiers

The photocathode of a second generation image intensifier can have a quantum efficiency of up to 25%.

S25 photocathodes are only available in the 18 mm diameter image intensifiers.

Typical QE

Typical quantum efficiency (%) of second generation image intensifiers as a function of wavelength (nm).
 

Second generation high QE
image intensifiers

The photocathode of a second generation high QE image intensifier can have a quantum efficiency of over 30%.

Please note that these image intensifiers are only available with a diameter of 18 mm.

Typical QE, 200 ns gate width

Typical quantum efficiency (%) of second generation high QE image intensifiers as a function of wavelength (nm).
 

Second generation fast-gated high QE
image intensifiers

The photocathode of a second generation high QE image intensifier can have a quantum efficiency of over 25%.

Please note that these image intensifiers are only available with a diameter of 18 mm.

Typical QE, 3 ns gate width

Typical quantum efficiency (%) of second generation high QE image intensifiers as a function of wavelength (nm).
 

Third generation image intensifiers

The photocathode of a third generation image intensifier can have a quantum efficiency of up to 50%.

Typical QE

Typical quantum efficiency (%) of third generation image intensifiers as a function of wavelength (nm).