Confocal Microscopy (CFM) | Transmission

Transmission experiments  in confocal microscopy sometimes also require filtering and shaping of the optical beam, and hence free-beam access instead of purely fiber-based can have quite some advantages in terms of flexibility.

attoCFM IV

This instrument literally consists of a ‚conventional‘ attoCFM I, which has a free-beam based channel with any of our apochromatic objectives above the sample, and a fiber-based channel from below just like in the attoCFM III.

So, despite fitting into any of our toploading cryostats, which usually features only 1 top and no side or bottom windows, this setup allows for at least either the excitation or the detection to be free-beam. This provides the user with all the flexibility of the external optics head just like in case of the attoCFM I for one channel (plus potential reflection measurements).

At the same time, there are 3 degrees of freedom for the sample (xy translation under the fixed LT-APO objective as well as focussing), and another 3 degrees of freedom in xyz to position the fiber-based objective underneath the sample.  All positioners are usually equipped with a /RES encoder for closed loop control, and there is an additional scanner for the sample in xy direction.

fundamentals, cfm transmission

  1. ASC400 scan controller
  2. LDM600 laser source
  3. LDM600 2nd detector
  4. attoCFM I external optics head incl. optional filters
  5. Optical top window
  6. Free-beam based cryogenic LT-APO objective
  7. Sample with xyz positioners and optional xy scanner
  8. Fiber-based cryogenic ashperic objective
  9. xyz positioner for fiber-based objective
  10. cryostat
  11. vacuum feedthrough for single-mode fiber