Hi all,
This week's talk will be given by Vincenzo Bruno, one of the PhD students in our group.
Epsilon-near-zero material as a platform for strong light-matter interaction.
Epsilon-near-zero
(ENZ) materials, both artificial and engineered, have attracted an increasing
interest due to the peculiar way how light interacts with such materials. The
ENZ range, where the real part of the permittivity (ε) approaches or crosses
the zero, can be obtained in different systems, including metal dielectric
composite or highly doped semiconductor. A particular family of natural ENZ
materials is the Transparent conductive oxide (TCO), as Indium Tin Oxide (ITO)
and Aluminum doped Zinc Oxide (AZO). Due to the low optical losses in the ENZ
region, these materials present a near zero index of refraction in the same
spectral range. As the effective wavelength in such material tend to infinity
as n → 0 in the ENZ region, a thick film of TCO could
behave essentially as the deeply subwavelength thin film. Was recently proved
that, in an AZO film, this near-zero response leads to an enhancement of the
non-linear response in terms of optical Kerr effect with a relative change of Δn over 400%
in a ultrafast temporal window. These features, together, make the AZO a
suitable platform for the study of fundamental physical problems in time
dependent materials, overcoming the usually weak light-matter interaction.
Same time, different room (hopefully it will be a little less cramped): 3pm Thurs 12th July, Kelvin 257.
Cheers,
Ash
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