Exploring the promise of the quantum realm
Rob Knobel is probing the ultimate limits of nanomechanical systems to develop and build tiny vapour sensors, which could be used as airport security tools to prevent terrorism or drug smuggling.
He and his students are using highly specialized equipment in the $5-million Kingston Nano Fabrication Laboratory (KNFL), which opened a year ago in Innovation Park, to fabricate nanosensors made from graphene, a form of carbon a single atom thick.
"Graphene is the strongest, lightest material yet discovered, and it has remarkable electrical and mechanical properties. We're developing graphene chemical sensors that can detect vapours in parts per billion or trillion concentration. These could potentially be used for detecting explosives or biological agents," says Dr. Knobel, an associate professor, the Chair of Engineering Physics and a Queen's Engineering graduate himself.
In his cutting-edge research, Dr. Knobel runs experiments in which small vibrating elements fabricated at the KNFL are cooled down to temperatures near absolute zero. These nanomechanical systems – moving devices with dimensions of a few nanometres, only a few atoms thick – vibrate under the influence of vanishingly small forces, and measuring their motion presents both scientific and engineering challenges. One purpose of these cryogenic experiments is to understand and measure how the properties and behaviour of these human-made nanostructures change in the transition from the macro world of classical physics to the quantum mechanics world on an atomic scale.
"Putting and measuring a nanomechanical system in the quantum world is important, fascinating and challenging science in its own right," he says.
But Dr. Knobel's fundamental research in the quantum realm also leads to the translation of this knowledge into promising real-world applications at room temperature. As he and his team push to develop superior nanoelectrical and nanomechanical devices with the extreme sensitivity needed to measure quantum effects, they are building better sensors with many possible practical applications of value to industry. These innovative nano-devices could be used for advanced mass spectrometry, more precise analysis of materials' properties, biosensors to detect proteins in the blood, or extremely high-resolution magnetic resonance imaging (MRI) to probe single molecules a few nanometres wide.
Dr. Knobel's research on the quantum behaviour of nanoscale devices is opening up new possibilities for quantum computing, a proposed way to rapidly speed up computing, and for quantum communications.
"Quantum communications is a way to create perfectly secure communications that no one could eavesdrop on," he says.
He has also built vibrating crystal beams that will respond to incredibly small forces at frequencies up to the microwave range, which could be used as filters to enable cell networks to handle many more phone calls.
The KNFL facility, a partnership between Queen's and CMC Microsystems, is an open facility for researchers and companies that want to make, characterize and test devices and materials with small dimensions from nanometre to millimetre. The new lab (funded through the Canada Foundation for Innovation, the Ontario Ministry of Research and Innovation, CMC Microsystems and Queen's) has been a catalyst for Dr. Knobel to launch collaborations with materials and chemical companies and other small and large industrial firms to test and advance these innovative technologies for broader practical uses.
"We're excited about the industry collaborations, and these are of great benefit to graduate students. This facility allows us to envision projects that were out of reach before and bring our research on quantum effects in nanomechanical systems closer to the real world and commercialization," he says.
Provided by Queen's University