II18MD, modulated image intensifier


The II18MD is the Image Intensifier with an 18mm diameter input screen that can be modulated and is digitally controlled. The II18MD modulated image intensifier is used as key component for FLIM (Fluorescence Lifetime Imaging Microscopy) in the homodyne frequency domain. The II18MD modulated image intensifier is designed for users who wish to apply the highest quality detector as part of their set-up for fluorescence lifetime imaging.

II18MD: modulated image intensifier
with control unit


Image intensifier
The high-resolution modulated image intensifier is mounted on the 1x C-mount camera port of a wide field fluorescence microscope. The gain of the image intensifier can be controlled by the voltage across the MCP and is typically in the range of 100 to 10,000 times. Also the voltage between cathode and MCP can be changed in order to control the gain. During modulation, the gain is modulated via the cathode voltage.
Depending on the application, the photocathode has to be chosen that has the appropriate sensitivity per emission wavelength. For GenII we normally offer either the S20 or the SuperS25 photocathode. For higher quantum efficiency (25% instead of 10%) the GenIII intensifier is offered, with the GaAs photocathode. See here for the photocathode characteristics?in FLIM applications:


A CCD camera has to be attached to the output of the II18MD image intensifier, so that the integrated high quality relay lens can transfer the output image onto the CCD of the camera (i.e. lens-coupled intensified CCD camera).

Integrated Control unit / Power supply
This unit contains the high voltage power supply and RF (Radio Frequency) amplifier. The control unit has a low voltage input to receive the external modulation signal that has to be amplified and biased with a variable DC photocathode voltage. Adjusting the MCP voltage controls the image intensifier gain. To prevent damaging, the image intensifier has an overload protection circuit that switches off the image intensifier when the light output becomes too high. Modulation frequencies?up to 120MHz.

Optional: Signal Generator
Instead of using an external modulation signal generator, we offer a built-in modulation signal generator into the integrated control unit/ power supply. This is the II18MDS.

Optional: Intensified CCD camera
Instead of the lens-coupled intensified CCD camera (II18MD + CCD), we offer our fiber-optic coupled image intensifier to CCD camera. This is the LI2CAM MD. This modulated intensified CCD camera is very compact and has a higher gain than the lens-coupled combination as a result of the more efficient and compact fiber coupling. The lens-coupled combination however allows easy detachment and exchange of camera from image intensifier by the user

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