This MSc level lecture focuses on advanced
optical laser spectroscopy techniques and their application to probe the
fundamental physical, electronic, vibrational and optical properties of
semiconductors, novel heterointerfaces and quantum confined
nanostructures. The course complements perfectly Semiconductor
Synthesis and Nanoanalytics (PH2189) presented by Prof. Sharp. Modern
laser systems are capable of generating intense, highly coherent
electromagnetic fields that interact with the electrons in a solid. Such
light-matter interactions give rise to a fascinating range of
phenomena, ranging from incoherent responses such as stead-state and
ultra-fast luminescence to coherent dynamical responses like four-wave
mixing (FWM), optical pumping and multi-dimensional time-resolved
spectroscopy having sub-picosecond temporal resolution. Besides
facilitating the direct characterization of semiconductor materials,
novel-heterointerfaces and nanoscale devices, these methods provide
direct information on fundamental opto-electronic processes such as
electron transfer, energy relaxation and thermalization, tunneling and
transport dynamics and the interactions between electrons in the solid
and diverse (e.g. vibrational, spin and magnetic) degrees of freedom in
the nanoscale solids. We will discuss both far-field optical
spectroscopic methods, that operate over length scales beyond the
diffraction limit, as well as nano-optical approaches capable of probing
systems at the size of the electronic wavefunction. The aim of this
module is to introduce MSc students to the state-of-the-art in optical
spectroscopic methods as they are utilized in the condensed matter and
semiconductor physics research communities. We will introduce the
underlying physics of the various methods, describe how they are
implemented experimentally in the lab and examine specific case
studiesfrom the literature that have led to key breakthroughs in
condensed matter and semiconductor physics.
Specific topics will include:
Review of key-semiconductor materials and fundamental light-matter interactions (2 lectures) Incoherent Optical Spectroscopy Methods (5 lectures) -Tools
of the trade (CW and ultrafast-lasers, photo-detectors, monochromators
and interferometers, signal detection / processing, cryogenics) -Photoluminescence -Nanoscale optical microscopy -Spectroscopy of single semiconductor nanostructures
Coherent (Non-Linear) Optical Spectroscopy (4 lectures) -Luminescence vs Reflection / Transmission Spectroscopy -Semiconductor Bloch Equations and Coherence Effects -Strong Excitation Effects -AC Stark Effect and Transient Spectral Oscillations -Examples (FWM, Photon echo, Resonance Fluorescence) -Decoherence and Phase Relaxation in NWs (exciton-exciton, e-X and exciton-phonon interactions -Raman and Brillouin Scattering
Ultrafast Optical Methods (3 lectures) -Regimes towards equilibrium (relaxation, thermalization and recombination) -Pump-Probe Spectroscopy Methods -Probing Exciton and Phonon Dynamics in Bulk, QWs and QDs -Exciton Dynamics (Pico and Femtosecond Studies) -Light-emission and optical interactions in nanoscale environments
