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报告内容
摘 要
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Ultrafast fibre lasers are regarded as the next
generation light sources. They have wide applications in the fields of
optical communication, metrology, sensing, imaging etc.. Intensive studies
have been done on the generation of short pulses (i.e., sub 100 fs, few
cycle), high power, high energy and different wavelength window. The recent
development of ultrafast fibre laser research activities at AIPT has been
reviewed.
Polarisation, as
an important property of light pulses, has rarely been exploited. This is due
to the polarisation dependency of the approaches that used to achieve
ultrashort pulses such as nonlinear polarisation rotation, and nonlinear
interferometry. Recently, the development of carbon nanotube (CNT) and
graphene as low cost, compact, and polarisation independent saturable
absorber has offered us a more convenient approach to achieve ultrafast fibre
lasers. Using the CNT mode locked fibre laser, by properly adjusting the
intracavity polarisation controller, we have observed various polarization patterns
in the format of Poincare sphere under a number of mode locking regimes such
as soliton, soliton molecues, stretch pulse and harmonic mode locking. A
unique spiral pattern has been observed for the first time and recognized as
a polarization attractor. Using a home developed fast polarimeter, we have
also resolved the pulse to pulse polarisation dynamics which highlighted by a
triangular or linear pattern.
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