4K Cryostat-mounted THz Scattering Near Field Optical Microscope System.

Descriptions

The University of Surrey, acting through its Advanced Technology Institute, has been funded to establish a highly integrated facility for single ion implantation; quality assurance of silicon substrates with single impurity implants, and coherent control of the orbital state of the single silicon impurities for quantum technology applications. The primary atomic species of interest for these applications in silicon is phosphorus, but also include bismuth, selenium and others. The implanter is already under construction. A microscope is required for the single atom in silicon substrate quality assurance and for the coherent control of single silicon atom coherence.Based on their long experience of research in this area, the Investigators responsible for delivering the program believe that for imaging single, sub-surface dopant atoms in silicon with species specificity and THz control there is only one solution that will meet the objectives: a Scanning Near-field Optical Microscope (SNOM). The microscope system design must enable tip-enhanced optical measurements by elastic light scattering-SNOM (s-SNOM), as opposed to aperture-based-SNOM (due to the resolution and signal sensitivity requirements given). The s-SNOM must be mounted in a cryogen-free cryostat with very low vibration relative to the optical bench-mounted customized laser sources.The system is based on a Scanning Near-field Optical Microscope produced by Neaspec and a 4K optical table-integrated cryostat made by its parent company Attocube.1. Cryostat.The system will be based on a dry cryostat (requirement vii) which is integrated into a standard optical table (i.e. Newport) to allow the customizable laser system configurations with different THz bands described (xiii,ix). Having the cryostat actually integrated into the optical table, not sitting next to the optical table minimises the movement of the lasers and optics relative to the sample. The cryostat will provide = 2 views of optical access (xi) through room-temperature windows to the microscope focus via windows that can be changed to suit the laser wavelength. Windows are blankable for improved base temperature. The electrical access provided includes 66 DC lines (plus 6 internal ones) and 2 coaxial microwave lines for 2GHz (xi). The time required for evacuation and cooldown to 10K after a sample change will be less than 7 hours and the warm-up time from 10K will be approx. 3.5 hours (xii).2. Atomic-Force Microscopy (AFM).The cryostat design will provide sufficient vibration isolation for high-quality AFM measurements of the surface features with topographic RMS noise