attoAFM/CFM with Free-Beam Optics for NV Magnetometry

in top-loading dilution refrigerator

  1. Leiden Cryogenics dry DR
  2. top-loading insert
  3. attoCFM I external optics head for free-beam confocal microscopy
  4. vector magnet
  5. attoAFM/CFM microscope moduel for mK
  6. cryogenic objective
  7. AFM with the Akiyama probe
  8. sample


In close collaboration with Leiden Cryogenics and the Quantum Sensing group of Patrick Maletinsky (University of Basel, Switzerland), we have developed a complete mK AFM/CFM based on a closed-cycle top-loading DR. The system is used for quantum sensing and imaging at mK temperatures. The toploading probe minimizes the turnaround time upon tip or sample exchange to only ~8 hours instead of 24-48 hours for warming up the whole DR. Long turnaround time can quickly become a prohibitive shortcoming for efficient SPM measurements.

The combined AFM/CFM features a free-beam confocal microscope, with the attoCFM I external optics head sitting on top of the top-loading insert. Despite long distance to the magnetic field center where the sample is mounted, attoAFM/CFM allows for the full range of confocal applications with all the flexibility of having several optical channels featuring easy alignment and very high long-term stability. The microscope module itself has been completely redesigned for the mK environment, as well as carefully thermalized and wired. In this configuration, a base temperature of 38 mK at the sample location has been achieved.