Fluor lens

FL FLUOR or NEOFLUOR stands for fluorite and indicates the lens is semi-achromatic ... 

A neMESYS high-pressure pump system (Cetoni, Germany) was used to pump the two fluids from two 50 pL SGE syringes (Supelco) onto the microchip, respectively. One fluid is the substrate solution, while the other is the BRET reaction mixture of thrombin and biosensor solutions. The flow rates of both streams were 20 pL/h. The microchip was placed on a microscope (Nikon Eclipse TE2000-U) stage for visualization and measurement. The bioluminescence emissions from the detection spot of the microchannel were collected with a 20x objective lens (Plan Fluor, Nikon). A dichroic mirror... 

The objective lens is the most important part of the optical system. All lenses have information engraved on them, and it is helpful to be able to interpret this. An old lens may only show its focal length, but a typical modern lens may have Pol 25/0.55 0.17/170. The letters indicate the type of lens, here strain-free, suitable for use with polarized light. Different manufacturers may use different abbreviations, but most are readily understood. The most obscure is FI or Fluor this indicates a high quality general purpose lens, once (but no longer) made using the mineral fluorite. 

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