Nanoprobe Scanning Quick Reference
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Chamber overview
The Nanoprobe Instrument (NPI) consists of a Focusing Optics Module which holds a Fresnel zone plate that is integrated with a central beam stop. This optic focuses through a differentially adjustable Order Sorting Aperture (OSA) matched to the beam stop so that the primary unfocused beam is blocked either by the central stop or the OSA permitting only primary focus (first order) beam downstream of the aperture- this OSA stage is also mounted on the FOM allowing the combination to be moved simultaneously. The combination of these two elements focuses the beam onto the Sample Module that provides translational and rotational control of the sample position. Laser interferometry is used to track the X/Y position of both the optic and sample stages relative to a common reference frame, allowing the user to scan the fine position of the optic differentially locked in to the sample position which continuously corrects uncontrolled positional drift over the scan.
Coarse scanning
Coarse or overview scanning of fields of view 50um-1mm is typically done using the Sample Y motion and Atto Z (or whichever linear motion axis is most coplanar with the sample surface as mounted) - while the zone plate is left stationary in the "optic in" position. These scans result in an up/down flip relative to a top-down optical image as shown. Notes: i) the Sample Y / Atto Z motions cannot be stepped less than 0.5um, for finer steps than that you will need to lock the hybrid motion and use fine scanning. ii) Sample X motions (under the rotation stage) are disabled as this will move the center of rotation relative to the beam axis iii) Coarse scanning Focus X / Focus Y is possible but should be avoided as this will move the optic out of the beam footprint, off the center of rotation, and out of focus simultaneously.
Fine scanning
Image for fine scanning here
Focusing
Image for focusing here
