attoAFM/CFM with Free-Beam Optics for NV Magnetometry
in top-loading dilution refrigerator
- Leiden Cryogenics dry DR
- top-loading insert
- attoCFM I external optics head for free-beam confocal microscopy
- vector magnet
- attoAFM/CFM microscope moduel for mK
- cryogenic objective
- AFM with the Akiyama probe
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.