NIST uses Optical Resonance to Probe Atoms

Have you ever stood under a dome and whispered, only to hear the echo of your voice come back much louder? Researchers at NIST used a similar principle to improve the atomic force microscope (AFM), allowing them to measure rapid changes in microscopic material more accurately than ever before.

An AFM works by using a minuscule sharp probe. The instrument detects deflections in the probe, often using a piezoelectric transducer or a laser sensor. By moving the probe against a surface and measuring the transducer’s output, the microscope can form a profile of the surface. The NIST team used a laser traveling through a circular waveguide tuned to a specific frequency. The waveguide is extremely close (150 nm) to a very tiny probe weighing about a trillionth of a gram. When the probe moves a very little bit, it causes the waveguide’s characteristics to change to a much larger degree and a photodetector monitoring the laser light passing through the resonator can pick this up.

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Hacklet 111 – Advanced Microscopy Projects

Last week on the Hacklet we covered optical microscopy projects. Those are the familiar scopes that many of us have at work or even at home on our benches. These are scopes that you typically can use with your eye, or an unmodified camera. This week we’re taking a look at more extreme ways of making small things look big. Electron streams and the forces of a single atom can be used to create incredibly magnified images. So let’s jump right in and check out the best advanced microscopy projects on!

blubeamWe start with [andreas.betz] and BluBEAM – a scanning laser microscope. [Andreas] aims to create a scanning confocal microscope. The diffraction limit is the law of the land for standard optical microscopes. While you can’t break the law, you can find ways around it. Confocal microscopy is one technique used quite a bit in medicine and industry. Confocal scopes are generally very expensive, well outside the budget of the average hacker. [Andreas] hopes to break that barrier by creating a scanning confocal microscope using parts from a Playstation 3 BluRay optical drive. Optical drives use voice coils to maintain focus. [Andreas] had to create a custom PCB with a voice coil driver to operate the PS3 optics assembly. He also needed to drive the laser. BluBeam is still very much a work in progress, so keep an eye on it!

stmNext up is [MatthiasR.] with DIY Scanning tunneling microscope. Open atmosphere scanning tunneling microscopes are popular on I covered [Dan Berard’s] creation in Hacklet 103. Inspired by Dan, [Matthias] is building his own STM.

Environmental vibration is a huge problem with high magnification microscopes. [Matthias] is combating this by building a vibration isolation platform using extruded aluminum. He’s currently working on the STM preamplifier, which amplifies and converts the nano amp STM values to voltages which can be read by a digital to analog converter. [Matthias] is using the venerable Analog ADA4530 for this task. With an input bias of 20 femtoamps (!) it should be up to the task.

desemNext we have [Jerry Biehler] with Hitachi S-450 Scanning Electron Microscope. Scanning electron microscopes have to be the top of the microscopy food chain. Jerry got his hands on a 1980’s vintage Hitachi SEM which was no longer working. The problem turned out to be a dodgy repair made years earlier with electrical tape. Fast forward a couple of years of use, and [Jerry] has done quite a lot to his old machine. He’s learned how to make his own filaments from tungsten wire. The slow oil diffusion vacuum pump has been replaced with a turbomolecular pump. The SEM now resides in [Jerry’s] living room, which keeps it at a relatively constant temperature.

Bild1Finally, we have [beniroquai] with Holoscope – Superresolution Holographic Microscope. Holoscope is a device which increases the resolution of a standard camera by using the physical properties of light to its advantage. Precise tiny shifts of the object being magnified cause minute changes in a reflected image, which is captured by a Raspberry Pi camera. The Pi can then reconstruct a higher resolution image using the phase data. [Beniroquai] has put a lot of time into this project, even sacrificing an expensive Sony connected camera to the ESD gods. I’m following along with this one. I can’t wait to see [beniroquai’s] first few images.

If you want to see more advanced microscopy projects, check out our new advanced microscope projects list! If I missed your project, don’t be shy, just drop me a message on That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of!

3D Printing Atomic Force Microscopy

[Andres] is working with an Atomic Force Microscope, a device that drags a small needle across a surface to produce an image with incredible resolution. The AFM can produce native .STL files, and when you have that ability, what’s the obvious next step? That’s right. printing atomic force microscope images.

The AFM image above is of a hydrogel, a network of polymers that’s mostly water, but has a huge number of crosslinked polymers. After grabbing the image of a hydrogel from an Agilent 5100 AFM, [Andres] exported the STL, imported it into Blender, and upscaled it and turned it into a printable object.

If you’d like to try out this build but don’t have access to an atomic force microscope, never fear: you can build one for about $1000 from a few pieces of metal, an old CD burner, and a dozen or so consumable AFM probes. Actually, the probes are going to be what sets you back the most, so just do what they did in olden times – smash diamonds together and look through the broken pieces for a tip that’s sufficiently sharp.

A DIY Atomic Force Microscope


For looking at really small stuff, an optical microscope will only go so far. Looking at things at the nanometer level, though, usually requires some sort of electron microscope, with all the hassle of vacuum chambers and high voltages. There is another way to investigate the domain of the very small: an atomic force microscope. Unlike their electron spewing brothers, they don’t require high voltages or hard vacuums. They can also be built for about $1000, as [whoand] over on the Instructables shows us.

Instead of shooting light or electrons at an object and picking up the reflections, an atomic force microscope drags a very, very tiny stylus across an object. This stylus is attached to a probe that will reflect laser light off of it into a photosensor, eventually rendering an image on a display. [whoand] is using a laser diode and pickup unit from a DVD-ROM drive for the optical pickup unit, a frame made from soldered together PCBs, and a few piezos to vibrate the probe.

The probes themselves are incredible pieces of engineering with a tip size of a few nanometers. They’re consumable, and expensive, ranging from $20 to $500 per probe. Still, with these probes, [whoand] can look at the pits in a CD or DVD, measure the surface of an eraser, or check out the particulate matter floating around in the atmosphere in Beijing.

Thanks [Rob] for the tip.