2015 CAP Congress / Congrès de l'ACP 2015

Ultrafast imaging of nonlinear terahertz pulse transmission in semiconductors

15 Jun 2015, 14:15

15m

CCIS L2-200 (University of Alberta)

Oral (Student, Not in Competition) / Orale (Étudiant(e), pas dans la compétition) Division of Atomic, Molecular and Optical Physics, Canada / Division de la physique atomique, moléculaire et photonique, Canada (DAMOPC-DPAMPC) M1-9 Ultrafast and Time-resolved Processes (DAMOPC) / (DPAMPC)

Speaker

Haille Sharum (University of Alberta)

Description

Terahertz pulse spectroscopy has been widely used for probing the optical properties and ultrafast carrier dynamics of materials in the far-infrared region of the spectrum. Recently, sources of intense terahertz (THz) pulses with peak fields higher than 100 kV/cm have allowed researchers to explore ultrafast nonlinear THz dynamics in materials, such as THz-pulse-induced intervalley scattering in semiconductors. Here, we use a gated intensified CCD camera and full-field electro-optic imaging with femtosecond laser pulses to directly observe dipole electric fields arising from shift currents induced by intense THz pulses in n-doped InGaAs. Voltage pulses generated by the THz-pulse-induced shift currents are also measured directly on a high speed oscilloscope. The polarization of the shift current with respect to that of the THz pump beam is determined. The simultaneous measurement of both the induced dipole and transmitted THz pulse allows for sub-picosecond resolution imaging of nonlinear THz dynamics in semiconductors.