Syllabus
1. Historical overview and motivation for spectroscopy in THz spectral range
2. THz time-domain spectroscopy; coherent methods of generation and detection of ultrashort THz pulses: photoconductive switches, optical rectification (chi2, chi3 processes), spintronic approach; remarkable properties: direct observation of light oscillations, phase-sensitivity of the detection, time resolution, high-field THz pulses (nonlinearities in THz spectroscopy)
3. Principles of steady-state and ultrafast THz spectroscopy. Bulk materials, thin films
4. Ultrashort THz pulses: description beyond quasi-monochromatic approximation (Gouy phase shift and its implications for THz spectroscopy)
5. Other sources THz radiation (Backward wave oscillators, Gunn and Schottky diodes, High-electron-mobility transistors, photomixing, Quantum cascade lasers, Large scale facilities: Free electron laser, THz in synchrotron). Thermal detectors of THz radiation.
6. THz spectroscopy in solids: - dielectric, ferroelectric, multi-ferroic materials (phonons, magnons, soft modes - application on structural phase transitions, electromagnons) - semiconductors (doped, photoexcited semiconductors - dynamics of charge carriers), semiconductor nanostructures, disordered systems - superconductors, graphene, other materials
7. Propagation and manipulation of THz radiation: tunable materials for THz applications, photonic structures and metamaterials, plasmonics, opto-THz modulators
8. THz imaging - applications; near-field THz microscopy (principles and applications)
9. Visit of the THz spectroscopy lab at FZÚ AVČR
Annotation
The course will provide the basis for the spectroscopy in the THz spectral range (~ 0.1-10 THz) and a survey of current THz technology and its applications. Intensive exploration of the THz region has become possible only about 20 years ago owing to the development of the so called time-domain THz spectroscopy - a special accent will be therefore put on this technique.
Due to fast development of THz technologies the content of the lectures will be continuously updated.