Alain Haché (born 1970) is an
experimental
An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs whe ...
physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...
, a
professor
Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other tertiary education, post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin ...
at the
University of Moncton, Canada.
From 2003 to 2013 he held the
Canada Research Chair
Canada Research Chair (CRC) is a title given to certain Canadian university research professors by the Canada Research Chairs Program.
Program goals
The Canada Research Chair program was established in 2000 as a part of the Government of Canada ...
in
photonics
Photonics is a branch of optics that involves the application of generation, detection, and manipulation of light in the form of photons through emission, transmission, modulation, signal processing, switching, amplification, and sensing. E ...
.
He is also the author of ''The Physics of Hockey''
and ''Slap Shot Science'',
two
popular science
Popular science (also called pop-science or popsci) is an interpretation of science intended for a general audience. While science journalism focuses on recent scientific developments, popular science is more broad ranging. It may be written ...
books on
ice hockey
Ice hockey (or simply hockey in North America) is a team sport played on ice skates, usually on an Ice rink, ice skating rink with Ice hockey rink, lines and markings specific to the sport. It belongs to a family of sports called hockey. Tw ...
.
Haché was born in
Tracadie, New Brunswick Tracadie is an unincorporated place in New Brunswick, Canada. It is recognized as a designated place by Statistics Canada.
Demographics
In the 2021 Census of Population conducted by Statistics Canada, Tracadie had a population of 5,349 living in ...
in 1970. In 2002, he and undergraduate student Louis Poirier transmitted
faster-than-light
Faster-than-light (superluminal or supercausal) travel and communication are the conjectural propagation of matter or information faster than the speed of light in vacuum (). The special theory of relativity implies that only particles with zero ...
electrical pulses through a 120-metre long "
photonic crystal
A photonic crystal is an optical nanostructure in which the refractive index changes periodically. This affects the propagation of light in the same way that the structure of Crystal structure, natural crystals gives rise to X-ray crystallograp ...
" made of
coaxial cable
Coaxial cable, or coax (pronounced ), is a type of electrical cable consisting of an inner Electrical conductor, conductor surrounded by a concentric conducting Electromagnetic shielding, shield, with the two separated by a dielectric (Insulat ...
s of alternating
characteristic impedance
The characteristic impedance or surge impedance (usually written Z0) of a uniform transmission line is the ratio of the amplitudes of voltage and current of a wave travelling in one direction along the line in the absence of reflections in th ...
(12 pairs of 50
Ω and 75 Ω cables).
The experiment showed that the pulse envelope was recreated at the end of the cables at a speed of >3
''c''. This speed represents the
group velocity
The group velocity of a wave is the velocity with which the overall envelope shape of the wave's amplitudes—known as the ''modulation'' or ''envelope (waves), envelope'' of the wave—propagates through space.
For example, if a stone is thro ...
, but the amplitude of the signal also drops in such a way that the energy transmitted never exceeds, at any given time, the energy that would have been transmitted by same pulse travelling in a vacuum.
References
Further reading
*
External links
Alain Haché's webpage @ Université de Moncton
Alain Haché's scientific contributions@ Google Docs
Canadian physicists
1970 births
Living people
Canada Research Chairs
Academic staff of the Université de Moncton
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