State-of-the-art Systems
Retrieve nano-features over millimeter ranges ! closed loop scanning & global sample coordinates
Science and technology delve deeper and deeper into the nanoworld . In particular , scanning probe & confocal microscopy have been concerned with features on the nanoscale ever since its invention . Reliably scanning over tens of micrometers range down to a few hundred nm is comparatively easily achieved by using piezo based scanners .
However , using piezo-based scanners usually relies on the assumption that the relation between applied voltage and displacement is linear . In reality , most scanners show large non-linear behaviour and hysteresis , especially for large scan ranges . Creep , i . e . drift in position after approaching a certain location , is a further phenomenon which is common to all piezo scanners .
In many experiments , reproducibly locating a small feature on a surface is crucial , and sometimes hysteresis and non-linearity in the acquired image are not acceptable . Sometimes , SPM images need to be evaluated for particularly and for the specific mutual distances of certain features , and hence , any distortions due to those nonlinearities may impede such analyses significantly .
total available range up to5 mm up to5 mm
Much more often , however , finding a certain region of interest or a particular feature on a macroscopic sample at all , or retrieving such locations repeatadly is a critical task .
Based on our patented FPSensor , a fiber-based interferometer , our microscopes can now be equipped with position closed loop sensors with featuring a steady-state resolution of down to 1 nm even in a , despite the cryogenic working environment .
At the same time , we implemented a fully digital scan engine in the ASC500 SPM controller , which now features location based data acquisition ( as opposed to time-triggered data acquisition on open loop systems ). In closed loop mode , this results in perfectly linearized images . The sophisticated scan engine even allows for an adjustment of the scan acceleration to smoothen the scanning motion at the turning points , which can be is especially useful especially for higher scan speeds .
The most useful new features however is that since the FPSensor covers the full 5 mm x 5 mmm range of the positioners , the scan widget now contains ‘ global ’ sample coordinates : usually , the maximum range accessible in closed loop mode is limited by the maximum range of the scanners . If the user wants to scan outside of this area , he can simply use the global sample coordinate system for navigation . To further facilitate this , any measured SPM images can simply be decorated onto the scan widget ’ s sample ‘ canvas ’ via dragand-drop , where they are put exactly at the measured coordinates . Hence , a virtual map of the whole sample gradually evolves within the scan widget .
Retrieving regions of interest on the nanoscale , which has always been extremely difficult and time consuming especially at low temperatures , is now an easy task thanks to this global sample coordinate system .
CUSTOMER FEEDBACK
Prof . Dr . Peter Michler
Our attoCFM I LT-lithography setup is not only the best choice when it comes to stability requirements . Its closed loop scanning feature also allows us to optically pre-select quantum dots suitable for desired experiments and mark them in-situ via lithography with nanometric precision .*
( University of Stuttgart , Germany )
For more details , see *[ 1 ] Sartison et al . Scientific Reports 7 , 39916 ( 2017 )