Dr. Jean-Michel Ménard

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Full name	Dr. Jean-Michel Ménard
Summary	Using Ultra-Fast Terahertz for non-invasive security and medical imaging and to test for pathogens in the food industry
Type of researcher	Principal Investigator
Introduce yourself, your experience and your credentials	Research conducted in our group focuses on improving the general understanding of quantum interactions in solid state and developing ultrafast optical tools to manipulate them. Most specifically, experimental techniques based on time-resolved terahertz spectroscopy allow us to investigate highly dynamical phenomena such as Bose-Einstein condensation of polaritons in semiconductor microcavities and quantum phase transitions in strongly correlated materials.
Describe your research	Our research group uses lasers and custom optical tools that we design here in the lab to study materials. Some of these materials are very new and very intriguing such as superconductors, two-dimensional materials, and semiconductor heterostructures. But we are also interested in materials that we know from our everyday life such as polymers and proteins or chemicals that we find in the air. This is the Ultra-Fast Terahertz Lab and what I mean by terahertz is a region of light such as infrared light or ultraviolet. Light is composed of an oscillating electric and magnetic fields, and visible light— the one that we see — is only a very small region of the full electromagnetic spectrum of light. In our lab, we specialize in the generation and detection of terahertz light. It’s a region that corresponds to roughly the far infrared and mid infrared part of the electromagnetic spectrum, but we call it terahertz because we can, here, resolve experimentally the oscillating electric field of that light, which has a frequency of 10 to the 12 (1012) Hertz or 1 terahertz. This region of light is very difficult to generate and detect. In our lab we use an ultra-fast near infrared laser generating very short bursts of lights which have a duration of the order of the femtosecond, which is ten to the minus 15 seconds (10-15). During this short time, the near infrared light is very intense and a terahertz pulse can be generated and detected throughout a nonlinear optical process inside a semiconductor crystal. We use a technique called electro-optic sampling to monitor directly the oscillating electric field of the terahertz pulse and this allows us to extract key information about the materials when the terahertz pulse is going through these materials — much more than you would get if you were only looking at the power of the light. Finally using a terahertz pulse allows us to look at ultra-fast phenomena involving microscopic particles in materials. It’s just like having a video camera with many, many frames per second, but in our case the full video is sometimes less than a few picoseconds in duration.
Explain its significance	Terahertz is a fast growing field of research and development in condensed matter physics. It is used to help us understand how nature works. It also allows us to discover new types of materials and to investigate quantum phenomena on the ultra-fast timescale. Terahertz also has very special applications in the field of security and medical imaging because it’s a non-invasive type of radiation that can pass through fabrics, ceramics, plastics; a lot of materials which are opaque to the visible region. Terahertz spectroscopy is also becoming more broadly used. This technique consists in looking at the colours of an object but not in the visible region but in the terahertz region. In pharmaceuticals for example these different colours can give you information about a medication, whether it contains its active ingredients or not. And also the food industry can use it for quality control purposes to look for example for the presence of bacteria. We also work closely with Canadian industry for example to develop compact ultra-fast terahertz sources and detectors. We are also interested in developing new types of components in a terahertz region such as terahertz filters and we think that this will help these companies and for sure our group to position ourselves as world leaders in terahertz photonics.