There is No Other AFM Like a Cypher
Asylum Research Cypher™ AFMs are in a class of their own. Our scientists and engineers optimized every design choice for the highest resolution, fastest scanning, best environmental control, and exceptional productivity. We invite you to learn about these important differences between Cypher AFMs and every other AFM.
There’s no more important or fundamental measure of AFM performance than resolution. Cypher AFMs routinely resolve features at higher resolution than other AFMs, including single atomic point defects.Raise your expectations —
Cypher makes high resolution routine
Cypher isn’t the first AFM to resolve atomic point defects. The history of AFM is punctuated with occasional examples of spectacular resolution. The perfect tip, the ideal sample preparation, a quiet day, and a healthy dose of good luck — and sometimes an image emerges unlike any other you have seen before.
These examples became known as “hero” experiments because they required heroic effort and patience. These kinds of results are now obtained routinely on Cypher, a feat that no other AFM dares to claim or attempts to demonstrate.
Cypher is simply better by design
It’s no accident that Cypher gets higher resolution than other AFMs. The path between the sample and tip (the “mechanical loop”) is very short and stiff. This is the most critical contributor to low noise. Combined with the integrated acoustic enclosure, Cypher is nearly immune from environmental noise. Amazingly, Cypher is normally used with no additional vibration isolation, yet it achieves a vertical noise floor of <15 pm, at least 50% lower than most AFMs.
What's the difference between single atomic point defect resolution and atomic lattice resolution?
Crystals invariably contain defects, including point vacancy defects where just a single atom is missing in an otherwise uniform atomic lattice. Yet many “atomic resolution” AFM images show a perfect, defect-free crystal face. Why is this so common? Though it is possible for an area to be free of defects for a time, more often these images are exhibiting a phenomena where a blunted AFM tip prevents the AFM from “seeing” the defects. When the AFM tip ends in a plateau of several atoms instead of a single protruding atom, the tip can skim past point defects without detecting them (see figure on right). More complex tip convolution effects can occur at steps where the edge interacts with other atoms farther up the tip.
Cypher AFMs routinely observe single atomic point defects in the crystal face, isolated from step edges and often persisting from one scan frame to the next. No other AFM routinely achieves this resolution. Many never do. It’s not just a matter of finding a sharp tip, but more importantly it is about preserving that tip sharpness throughout imaging. A single uncontrolled tip-sample collision caused by vibration or poor feedback can blunt the tip. The extreme stability of Cypher AFMs allows point defect resolution to continue from scan to scan for periods of hours.
New, smaller cantilevers allow compatible AFMs to scan 10–100 times faster than conventional AFMs. Cypher is unique among these few fast scanning AFMs because it enables high speed tapping mode imaging while still supporting all the other modes and accessories that you expect. This is not true of other fast scanning AFMs where you need to use an entirely different AFM or else remove the fast scanner and replace it with a conventional scanner to do more than just scan topography.
Cypher uses the smallest, fastest probes
Smaller cantilevers are faster because their resonance frequency scales with size. To use these probes an AFM must be able to focus its deflection sensing laser to a very small spot. The Cypher small laser spot is just 3 x 9 μm in size which can be used with even the smallest commercial probes.
Not just faster, also lower noise
Small cantilevers also help enable higher resolution because they have intrinsically lower thermal noise in a bandwidth around their resonance compared to conventional cantilevers with the same spring constant. Contact mode or force mapping modes operate in an even worse noise regime that’s usually dominated by larger 1/f noise sources. This is a fundamental advantage of tapping mode with small cantilevers and one reason that Cypher consistently achieves higher resolution than other AFMs.
No compromises in the Cypher scanner —
fast, low noise, low drift and closed-loop
The Cypher S and Cypher ES scanners feature exceptional performance as judged by any measure. They have a generous 30 μm XY and 5 μm Z range. The XY scanner operates in closed-loop for maximum scan accuracy, with <60 pm XY sensor noise, more than 50% lower than most of its competitors (i.e., the ones that aren’t limited to open-loop). Low drift maximizes resolution and minimizes jitter in movies of dynamic events. Optional thermal stabilization can make it negligible.
Tapping mode is by far the dominant imaging mode in the world of AFM, measuring not just topography, but also mechanical, electrical, and magnetic properties. Typically, piezoacoustic excitation is used to drive the cantilever oscillation. Though often used because it is simple to implement, the piezo-driven response of cantilevers is far from ideal in both air and liquids.
Asylum’s blueDrive excitation mechanism produces an almost perfect response by directly exciting the cantilever photothermally using a modulated blue laser. Photothermal excitation is available exclusively on Asylum Research Cypher AFMs.
Simple setup, even when imaging in liquid
AFM cantilevers have simple frequency responses in theory. In practice though, piezo drive mechanisms excite other system resonances in addition to the cantilever, which distorts the measured response, even in air. In liquid, additional factors make the response even worse. Because it uses light, blueDrive excites only the cantilever, not other mechanical components in the AFM. This produces an exceptionally clean response. This enables simple, reliable automated cantilever tuning, even in liquids and other challenging conditions.
Remarkably stable imaging
Piezo-driven cantilever responses are not only frequency dependent, but they also vary with time. As the response drifts relative to the setpoint, the tip-sample force changes. It can be difficult to distinguish true sample dynamics from artifacts of this drift. The direct excitation provided by blueDrive is highly immune to drift, so the imaging force remains stable throughout the experiment and under full control. This enables stable imaging over extended durations with no need to readjust the amplitude setpoint.
Obtain nanomechanical properties
The cantilever amplitude and phase response is interpreted quantitatively in many AFM techniques including nanomechanical techniques like AM-FM Viscoelastic Mapping, Loss Tangent imaging, and Contact Resonance Viscoelastic Mapping. Often, these analyses assume an ideal cantilever response (e.g. simple harmonic oscillator model). The accuracy of the derived physical information is therefore limited by the actual quality of the cantilever response. The measured resonance using blueDrive is incredibly clean and consistent with theory. Therefore the frequency, phase and quality factor can all be measured and tracked with greater accuracy and precision, yielding more accurate material properties.
The Cypher ES was designed from the start for environmental control, including temperature, operation in liquids with or without perfusion, and broad chemical compatibility. Most AFMs are designed first for ambient operation in air with limited environmental control only considered later. So it isn’t surprising that the Cypher ES provides environmental control solutions that work better and are easier to use.
Every Cypher ES starts with a sealed cell, pressured tested to at least 35 kPa. For use in liquid, this ensures that liquid will not leak anywhere that it can cause damage and enables an equilibrium that prevents evaporation of the liquid volume. In gas, it enables control of the composition (e.g. humidity, use of inert gases, etc.). Gas or liquid can be exchanged or perfused through sealed tubing connections. The entire sealed cell can be handled independently from the AFM, for instance, to transfer a sample from a dry glovebox.
Exquisite temperature control
Temperature control of the sample is achieved in the sealed cell, which is beneficial, for instance, to prevent oxidation of samples at high temperature or condensation on samples at low temperature. Two temperature control ranges are available, ambient to 250°C and 0°C to 120°C. Both may be used in either gas or liquid environments. A highly symmetric mechanical design and the use of low-CTE materials keeps drift very low as a function of changing temperature.
Chemical compatibility even in the harshest environments
All materials in contact with the sample and environment were selected for excellent chemical compatibility. When used in liquid, the liquid only touches the samples, cantilever holder (fused silica) and probe clip (choice of stainless steel or PEEK). Gases and liquid vapors also contact the FFKM O-ring that seals the cantilever holder and the FFKM bellows that seals around the scanner. These materials allow the use strong acids and bases, aggressive organic solvents, and most other gases and liquids.
Hassle-free design for easy operation
The environmental control options were designed to be not only effective, but also easy to use. The number of required components is minimized, including no external controller and no liquid coolant pump for heat exchange. A built-in pressure sensor can be used to verify that the cell is sealed. Components are designed to be easily cleaned, without crevices that might accumulate contamination. Users experienced with other AFMs might be conditioned to avoid environmental control wherever possible. The Cypher ES is designed to be free of hassles so that environmental control can be used whenever it is beneficial.
Successive tapping mode topography images of a calcite crystal in water. The repeated point defects demonstrate the true atomic resolution capabilities of the Cypher AFM. Arrows indicate scan direction. Scan size 20 nm.
Three sequential images show the repeatability of atomic scale defects on the cleavage plane of a calcite crystal
imaged in water with the Cypher AFM. Scan size 10 nm.
Blunt AFM tips skim over single point defects and have complex interactions with step edges. Most AFMs cannot preserve a sharp tip, so they only achieve lattice resolution.
An atomically sharp AFM tip can detect single point defects. Cypher AFMs are extremely stable, so the tip can remain sharp for hours.
The surface of a freshly cleaved calcite crystal in humid air reconstructs on the time scale of minutes to hours. This movie shows a 2 μm area scanned at 195 μm/s (40 Hz scan rate, 13 seconds per frame) for nearly five hours. The movie was taken in tapping mode using a 10 μm cantilever with a resonance frequency of 3.5 MHz. See more Cypher fast scanning videos.
(Left) Fast scanning cantilevers are 10–20x shorter than conventional cantilevers, (Right) The Cypher laser spot is perfectly sized for even the smallest conventional cantilevers.
blueDrive concept, sketch (left), actual top view optical image (right) showing the laser focus positions.
(Top) Representative tunes for an Olympus BL-AC40TS cantilever. (Bottom) Amplitude stability measured under the same conditions.
DNA imaged in buffer using blueDrive on a Cypher S AFM. Both the major and minor groove of the DNA double helix are clearly resolved. Image size 120 nm. See more images in the blueDrive image gallery.
AM-FM Viscoelastic Modulus Mapping of a polystyrene (PS) / polycaprolactone (PCL) polymer thin film on mica. Image was taken using blueDrive photothermal excitation on a Cypher S AFM at 2 Hz. Scan size 5 μm. See more images in the nanomechanics image gallery.
Whether used in gas or liquid, the Cypher ES operates in a sealed cell for superior environmental control in
all situations. Here operation is depicted in a liquid droplet.
A blend of polystyrene (PS) and polypropylene (PP) was heated to 140°C to melt the syndiotactic PP and then cooled at a constant rate while imaging at one frame per minute. As the sample cools, the continuous PP phase first nucleates and then forms partly ordered, semi-crystalline regions. Some of the regions form on top of the PS spherical domains.