Lambert Instruments

The II18MD is an Image Intensifier with an 18mm diameter input screen that can be Modulated in the range of 10-120 MHz and is Digital controlled. The II18MD modulated image intensifier is used as key component for FLIM -Fluorescence Lifetime Imaging Microscopy in the 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.

Components
The II18MD modulated image intensifier is provided with a control unit containing 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.

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.

The II18MD modulated image intensifier is mounted on the 1x C-mount camera port of a widefield fluorescence microscope. A CCD camera has to be attached to the output of the II18MD modulated image intensifier, so that the integrated high quality relay lens can transfer the output image onto the CCD of the camera. What kind of CCD camera suits for this application, can be discussed with the experts of Lambert Instruments.

Mostly the II18MD modulated image intensifier is used in combination with a modulated laser diode or an AO-modulated laser . This is advantageous when combining the fluorescence lifetime imaging with a spinning disk in order to obtain confocal lifetime imaging. Also the combination of lifetime imaging with TIRF -Total Internal Reflection Fluorescence has advantages with the use of laser diodes (or lasers), because a high power light source is required for the TIRF -Total Internal Reflection Fluorescence technique.