Adam V. Steele

Scientific Research and Education

Advanced Ion Sources

Since 2009 I have worked to develop new ion sources that will improve the performance of focused ion beam Instruments. These sources work by first laser-cooling and then photoionizing an atomic vapor. Using these techniques ion sources of chromium, lithium, and cesium have been created. The latest cesium source is very high-performing and is now being developed as one of the first commercial applications of laser-cooling.

Since 2013 this work has been done with my colleagues at zeroK NanoTech. From 2009-2012 this research was done at NIST as part of my post-doctoral fellowship with the group of Jabez McClelland.

Tin spheres on a carbon substrate. The field of view is 10 µm. To generate this picture the focused beam is rastered across the surface. In each pixel the beam sits for about 16 µs, during which so-called secondary electrons generated by the impact of the ion beam are collected and interpreted as a grey level.

This image was taken using the zeroK LoTIS Cs+ FIB prototype.

Laser Cooling

The common thread in all of my physics research is the use of lasers to bring an atoms from room temperature or above down to a as low as a few millionths of a degree of absolute zero. Laser-cooling was critical to the creation of the ion sources described above, and can be applied to reduce the temperature of both neutral atoms and ions.

Learn more at Wikipedia.

COMING SOON: a fun guided tour of laser cooling

Ion and Atom Trapping

Longer term confinement is usually needed in order to achieve and make use of the ultra-cold temperatures enabled by the laser cooling. In the context of this section, long-term means timescales longer than those required for a uncooled particle to pass through the lasers.

In the video above you can see a few dozen 138Ba+ ions fluoresce under the influence of laser light. Each dot of light here really is a single atom! The video is real-time, and the field of view left-to-right is about a millimeter if I recall correctly. They are confined in a radio frequency ion trap. The crystaline structure they collectively exhibit owes the fact that they have been brought to very cold temperatures by the laser-cooling process. They occasionally shift position when the crystal is disturbed by a collision with a background gas molecule. You may also note two positions in the crystal where ions appear to be 'missing'. There are ions here, but since they are of a different isotope (likely 137Ba) they do not fluoresce at the same laser frequencies as does the 138Ba+. The structure is one that minimizes the energy of the overall arrangement, this is often called a Wigner (or Coulomb) crystal.

Publications

Education

I hold a PhD from Georgia Institute of Technology and a B.S in physics and computer science from Carnegie-Mellon University.

Affiliations

My Company

zeroK NanoTech Corporation

I co-founded zeroK with Brenton Knuffman to commercialize a new ion source technology to be used with focused ion beam instruments. I have been intimately involved in all aspects of the company's operations since inception. Most of the skills I detail below were acquired by running zeroK. These include fundraising, grant and patent writing, contract and license negotiation, business plan writing and execution, and project management.

Fundraising

zeroK had raised over $3M (as of 2016). A large portion of this from a development contract with a large semiconductor company. We also have been awarded grants, principally through the National Science Foundation's SBIR program [LoTIS Grant]. We were also awarded grants from Maryland TEDCO.

Contract Negotiation

As one of the two founders of a small startup I took a lead role in our contract negotiations. Our largest early-stage investment was a development contract with a global semiconductor company. We were looking for funding to build and alpha and they wanted certain access rights to our ion source technology. This turned out to be quite a complex negotiation that required figuring out creative ways to address the concerns of both parties.

Another important early negotiation was the exclusive license for our core technology from the US government. Since it was invented during my time at at NIST we needed to secure exclusive rights before we began fundraising.

The experience of negotiating these contracts has given me some education on constructive ways to close a deal, balancing both parties need for specificity while maintaining trust.

Grant Writing

The competition for grant funds can be quite strong. A well-prepared application considers the aims of the funding agency, and convincing case for the project outputs with the right level of technical detail. When preparing zeroK's application for the NSF SBIR Phase II award, our NSF advisor described our document as "the best he has ever seen". Perhaps hyperbole, but zeroK has been awarded every grant for which it has applied so far.

zeroK won 1st place in the faculty category at the University of Maryland's Business Plan competition in 2012. This was right when zeroK was formed. That's me with the long hair, my co-founder Brenton to my left.

Patents & IP Protection

Obtaining good intellectual property protection can be time consuming and expensive. An understanding of what options, nationally and internationally, are available and the time frames on which action is required will critically inform your IP strategy. Your IP counsel will give you a menu of options, you will have to decide based on an analysis of the market the regions in which patent prosecution will be worth the costs.

Additionally, in order to make the most of your IP counsel's assistance, you should be familiar enough with the format of a patent's text and claim structure to write a comprehensive first draft yourself. As skilled as your counsel may be, it is unlikely that he/she will better understand how and why your invention is novel and non-obvious more than you do. Post-submission, you will need to help your counsel to draft sensible replies to office actions. Be sure to mention the idea of having a phone call with the examiner directly; we found it to be quite helpful, but some lawyers don't have this on their radar.

At zeroK every significant IP action, from writing to responding to office actions was done with heavy involvement of the inventors.

Coding Projects

I program both for work and as a hobby.

N-body physics

Developing an accurate model of zeroK's ion source required accounting for ion-ion interactions. I developed some software that allowed the size of these effects to be accurately predicted by performing a Monte-Carlo analysis of thousands of simulated ions. This code formed the basis for a paper [ 1 ].

This code was developed in C and later upgraded to modern C++. It has a multithreaded design and allows a fairly fast simulation of the evolution beams of a nanoamp or greater. It was written in a modular fashion which should allow it to be used for other particle physics problems.

WebGL Laser Cooling Demo

In this project I used WebGL to create a particle 'simulation' of the laser cooling process. It was motivated by my observation that audiences to my technical talks on zeroK's ion source technology often had a difficult time visualizing how the technology's several separate laser cooling stages fit together.

The goal was not to come up with a model that realistically depicted the physics, but one that would give an audience a qualitative sense of how the particles flowed from one part of the system to the next and ultimately ionized. Also it should just look cool.

In the first iteration the physics calculation were done in javascript and the WebGL work was greatly aided by the three.js library. Later, to increase the number of particles that could be shown I moved the physics onto the GPU. Many of the straightforward ways of doing this (e.g.: compute shaders, transform feedback) were not available in WebGL, so I settled on the use of frame buffer objects.

The demo was not meant to run on the open web, mainly just on my laptop for presentations, so the instructions are a bit lacking, and it has only been tested for chrome. You can try it out here!