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We present a comparison of classical and recently developed communications interfacing technologies relevant to
scanned imaging. We adopt an applications perspective, with a focus on interfacing techniques as enablers for enhanced
resolution, speed, stability, information density or similar benefits. A wealth of such applications have emerged, ranging
from nanoscale-stabilized force microscopy yielding 100X resolution improvement thanks to leveraging the latest in
interfacing capabilities, to novel approaches in analog interfacing which improve data density and DAC resolution by
several orders of magnitude. Our intent is to provide tools to understand, select and implement advanced interfacing to
take applications to the next level.
We have entered an era in which new interfacing techniques are enablers, in their own right, for novel imaging
techniques. For example, clever leveraging of new interfacing technologies has yielded nanoscale stabilization and
atomic-force microscopy (AFM) resolution enhancement.
To assist in choosing and implementing interfacing strategies that maximize performance and enable new capabilities,
we review available interfaces such as USB2, GPIB and Ethernet against the specific needs of positioning for the
scanned-imaging community. We spotlight recent developments such as LabVIEW FPGA, which allows non-specialists
to quickly devise custom logic and interfaces of unprecedentedly high performance and parallelism. Notable
applications are reviewed, including a clever amalgamation of AFM and optical tweezers and a picometer-scaleaccuracy
interferometer devised for ultrafine positioning validation. We note the Serial Peripheral Interface (SPI),
emerging as a high-speed/low-latency instrumentation interface. The utility of instrument-specific parallel (PIO) and
TTL sync/trigger (DIO) interfaces is also discussed. Requirements of tracking and autofocus are reviewed against the
time-critical needs of typical applications (to avoid, for example, photobleaching), as exemplified in recent capabilities
for fast acquisition of focus with bumpless transition between optical and electronic position control. A novel
planarization approach is reviewed, providing a nanoscale-accurate datum plane over mesoscale scan areas without scanline
flattening. Finally, not to be overlooked is the original real-time interface: analog I/O, with novel capabilities
introduced in recent months. Here additional developments are discussed, including a resolution-enhancing technique
for analog voltage generation and a useful combination of high-speed block-mode and single-point data acquisitions.
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