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74-UV, 74-VIS Collimating
Lenses Instructions
Description
To obtain accurate data, the light entering the sample and the light collected after exiting the sample
must be well collimated. The 74-UV and 74-VIS collimating lenses screw onto the end of SMA-
terminated optical fibers and other sampling optics to convert divergent beams of radiation (light) into
a parallel beam.
Collimating lenses are useful for any optical setup that requires the acceptance or transmission of
parallel beams of light at the illumination source, at the entrance optics, or at both ends (illumination
and read) of the setup. That's important because the optical fibers Ocean Optics specifies for use with
its spectrometers and light sources have a field of view (FOV) of ~25° -- an acceptance angle that may
not be appropriate for some experiments. Collimating lenses are adjustable, providing FOV angles
from collimation (near 0°) to ~45°. Without the collimating lenses, the light would disperse more than
is required for efficient transmission and collection of the signal.
Using a collimating lens is easy. Screw a collimating lens onto the end of any SMA-terminated port to
collect, shape, or focus light.
Adjusting the Focus for Collimating Lenses
All collimating lenses are already adjusted at the time of manufacture such that light emerging from a
200 µm fiber/collimating lens assembly is collimated. To readjust the focus of light so that accurate
data is collected by the spectrometer, use the following procedure.
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Procedure
Adjusting the Focus of the Collimating Lens on Your Light Source
1.
Connect the fiber that you are going to use as the illumination fiber in your setup to the light
source. Ensure the connection is tight. The female SMA connector of the fiber must be
screwed all the way into the male connector of the lamp.