TimeResolved Photoemission Spectroscopy Supansa Musikajaroen D 5710287 Outline

Time-Resolved Photoemission Spectroscopy Supansa Musikajaroen D 5710287

Outline • Introduction • Time-resolved photoemission measurement • Experimental set up - Light source - Ultrahigh Vacuum (UHV) Analysis Chamber - Time Of Flight (TOF) Spectrometer 2

Introduction Time-resolved photoemission measurement : can offer the real time study of the dynamics of the electronic state in condensed matter used in investigation of the binding energies, dispersion and lifetimes of the electronic state on clean metal surface 3

Time-resolved photoemission measurement 4

Time-resolved photoemission measurement 5

Time and Energy Resolution Heisenberg uncertainty principle 6

Time-resolved photoemission measurement Figure 2. 6: Schematic two dimensional energy diagram of 2 PPE with vertical axis rep resenting the binding energy (with respect to the Fermi level) and the horizontal a. xis representing the temporal delay between the pump and probe pulses. At negative delay times the UV is the pump and the VIS is the probe. At positive delay times the pulses are reversed 7

Time-resolved photoemission measurement Transient electronic band structure in Tb. Te 3 monitored by tr. ARPES. Panels (a) and (c) show the excitation of the amplitude mode in weakly perturbative excitation regime, while panels (b) and (d) evidence ultrafast 'melting' of the charge ordered state. https: //arpes. stanford. edu/research/tool development/time resolved arpes 8

Time-resolved photoemission measurement Studying the unoccupied electronic states of Bi 2 Se 3 by 2 PPE. (a) A schematic of the 2 PPE processes utilized. Red and blue arrows represent 1. 5 e. V and 6 e. V photons, respectively. (b) Unoccupied electronic structure of Bi 2 Se 3 from the Fermi level to the vacuum level, revealing a second Dirac surface state. (c) Resonant optical excitation of the second surface state using 9 https: //arpes. stanford. edu/research/tool development/time 1. 5 e. V photons. resolved arpes

Experimental setup Time-resolved Pump-Probe Photoelectron Spectroscopy Time-Resolved ARPES http: //research. physics. berkeley. edu/lanzara/trarpes. html http: //www. ipc. kit. edu/mik/english/15_538. php 10

Experimental setup dichroic mirror (β barium borate) http: //research. physics. berkeley. edu/lanzara/trarpes. html 11

Experimental setup Schematic illustration of the experimental setup for time resolved high harmonic generation based XUV ARPES http: //pubs. rsc. org/en/content/articlehtml/2014/fd/c 4 fd 00042 k 12

Light Source Verdi diode pump laser 13

Experimental set up ������� delay time dichroic mirror (β barium borate) 14

Ultrahigh Vacuum (UHV) Analysis Chamber UV grade fused silica window TOF Sample of Bi 2212 mounted on a 1 inch copper puck Sample holder 15

Ultrahigh Vacuum (UHV) Analysis Chamber Ordinary sticky tape is used to cleave the surface of the sample. 2 samples (black spots) Ultrahigh Vacuum (UHV) Analysis Chamber checks the sample position through the hemispherical analyser. transfers a sample from the load lock into the main chamber. adjusts the manipulator to position the sample for tr. ARPES. http: //mpsd cmd. cfel. de/research lab 16 rutherapple. html

Time Of Flight (TOF) Spectrometer Multichannelplate detector 17

Time Of Flight (TOF) Spectrometer 18

Time Of Flight (TOF) Spectrometer http: //www. specs. de/cms/fro nt_content. php? idcat=223 19

Time Of Flight (TOF) Spectrometer 20

Thank you 21