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SUMMARY:Ultrafast chiroptical spectroscopy and microscopy
DTSTART:20260108T170000
DTEND:20260108T180000
DTSTAMP:20260525T204517Z
UID:c702a9be12947d0879b8dcfd9c311c0a5722035523d74b0024e09409
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Giulio Nicola Felice Cerullo\nAbstract: Chirality is u
 biquitous in nature\, and understanding of chiral properties is critical t
 o many applications in modern science and technology\, ranging from protei
 n function in biology and enantiomer differentiation in pharmaceutics\, to
  light control in plasmonics and metamaterials all the way to probing magn
 etic properties in spintronic and superconducting devices. The chiro-optic
 al response of a sample is manifested as a dependence of the complex refra
 ctive index on the handedness of circularly polarized light\, which can be
  probed by its imaginary part (circular dichroism\, CD) or its real part (
 optical rotatory dispersion\, ORD). The ultrafast chiro-optical response o
 f a sample is of broad interdisciplinary interest\, ranging from structura
 l dynamics of proteins to spin dynamics in semiconductors and magnetic mat
 erials to the nonlinear response of chiral plasmonic nanostructures. The m
 easurement of time-resolved CD or ORD is however experimentally challengin
 g\, because it requires the detection of the small photoinduced change of 
 an already small signal. Here we introduce two novel approaches to ultrafa
 st chiro-optical spectroscopy. We first present a broadband ultrafast chir
 optical spectroscopy setup which combines time-domain Fourier transform de
 tection and heterodyne amplification using a birefringent common-patt inte
 rferometer. Our method allows the detection of transient CD and ORD spectr
 a with sensitivity lower than 1 millidegree. We then discuss an ultrafast 
 widefield chiro-optical holographic transient absorption microscope which 
 uses a multiplexed off-axis holography scheme with two cross-polarized ref
 erence pulses. The holographic nature of the measurement enables retrieval
  of the electric field of the probe pulse and thus simultaneous detection 
 of the transient CD and ORD signals\, which can be reconstructed over a la
 rge field of view with high temporal (sub-100-fs) and spatial (sub-µm) re
 solution.\n \nAbout the speaker: Giulio Cerullo is a Full Professor in t
 he Physics Department at Politecnico di Milano\, where he leads the Ultraf
 ast Optical Spectroscopy laboratory. Prof. Cerullo’s research activity c
 overs a broad area known as “Ultrafast Optical Science”\, and concerns
  on the one hand pushing our capabilities to generate and manipulate ultra
 short light pulses\, and on the other hand using such pulses to capture th
 e dynamics of ultrafast events in molecules\, nanostructures and two-dimen
 sional materials (graphene\, transition metal dichalcogenides). He is a Fe
 llow of the Optical Society and of the European Physical Society (EPS) and
  Chair of the Quantum Electronics and Optics Division of the EPS. Prof. Ce
 rullo is recipient of an ERC Advanced Grant (2012-2017) and serves on the 
 Editorial Advisory Board of the journals Optica\, Laser&Photonics Reviews\
 , Scientific Reports\, Chemical Physics\, and Journal of Raman spectroscop
 y.\n\nThe seminar will be followed by an apero.\nPlease do not hesitate to
  get in touch\, if you would like to meet the speaker before his presentat
 ion!\n 
LOCATION:CH G1 495 https://plan.epfl.ch/?room==CH%20G1%20495 https://epfl.
 zoom.us/j/65019212614?pwd=hbVWPRVbAMTfkO08f7XHK3JuqDucsu.1
STATUS:CONFIRMED
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