General Features


Central part of the MICROFIBER-PAM is a fiber optic coupler consisting of a “beam splitter” to which two pairs of fibers are connected. This “four-port” coupler distributes light incoming from one fiber pair to the other pair where each fiber pair can function as input.

Typically, the fiber optic coupler conducts emission from an LED to the sample, and guides fluorescence from the sample back to a highly sensitive photomultiplier which is shielded against LED light by glass filters.

Both, light emission of the LED and fluorescence measurement by the photomultiplier are coordinated by the PAM-CONTROL unit.

The PAM-CONTROL unit allows stand-alone operation of the MICROFIBER-PAM but functions also as a physical interface for computer-controlled operation of the MICROFIBER-PAM.


Normally, the MICROFIBER-PAM uses blue LED light for fluorescence excitation but alternative LEDs emitting in the green and red spectral range are available (see Accessories).

Peak emission of the blue LED is 470 nm. The LED emits pulses of several μs duration to elicit the pulse-modulated fluorescence measured by the MICROFIBER-PAM, but also longer-lasting pulses which produce integrated light intensities which can saturate photosynthesis.