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VERSION:2.0
PRODID:icalendar-ruby
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VEVENT
DTSTAMP:20260512T162120Z
UID:https://www.mpsd.mpg.de/events/7760/42300
DTSTART:20161124T090000Z
DTEND:20161124T100000Z
CLASS:PUBLIC
CREATED:20161124T124145Z
DESCRIPTION: The possibility to manipulate the electrical properties of mat
 ter with very short opticalpulses is a fascinating field of research with 
 possible far reaching applications inmany relevant technological fields. T
 he first step towards the realization of this goal is to understand the ul
 trafast dynamics at the basis of light-matter interaction. Short and inten
 se pulses allowed us to investigate a very interesting regime where the ph
 oton energy becomes comparable to the cycle-averaged kinetic energy of the
  electrons in the field. As the optical response of the material transitio
 ns from a classical to quantum-mechanical description many intriguing effe
 cts co-exist in this regime and the importance of inter- versus intra-band
  transitions is still debated. We used attosecond transient absorption spe
 ctroscopy (ATAS) to study the optical response of polycrystalline diamond 
 driven by few-femtosecond\, intense (IIR ~1012 W/cm<sup>2</sup>) infrared 
 (IR) pulses. We monitored the system response by looking at the induced ch
 ange in the absorbance with a 250-as pulse centred around 40 eV. We observ
 ed the appearance of oscillating features which modulate at twice the IR f
 requency\, ωIR\, and fully recover after the interaction. Simultaneous ph
 otoelectron acquisition from a gas nozzle placed in front of the diamond t
 arget allowed us to study the phase relation of the oscillating features a
 nd the pumping IR field. We found that the timing of the diamond response 
 changes significantly with the probing energy and does not always follow t
 he IR field adiabatically. Ab initio calculations performed by coupling ti
 me-dependent density functional theory (TDDFT) in real time with Maxwell
 ’s equations reproduced the experimental observations. Further compariso
 n with a numerical two-band model allowed us to conclude that intra-band m
 otion dominates over inter-band transitions\, thus identifying the dynamic
 al Franz- Keldysh effect as the dominant mechanism in this regime. Our ana
 lysis constitutes an important step towards a full understanding of the op
 tical properties of dielectrics in the Petahertz regime.\nVortragende(r): 
 Matteo Lucchini
LAST-MODIFIED:20161124T124336Z
LOCATION:CFEL (Bldg. 99)\, Raum: Seminar Room V\, O1.109
ORGANIZER;CN=Angel Rubio:mailto:
SUMMARY:MPSD Seminar: Matteo Lucchini - Attosecond dynamics in polycrystall
 ine diamond
URL;VALUE=URI:https://www.mpsd.mpg.de/events/7760/42300
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