. . . . . "0"^^ . "GA202/98/P022" . . . . "Time-resolved terahertz spectroscopy of thin ferroelectric layers and GaAs/AlGaAs heterostructures"@en . . "Postup a metodika prac\u00ED je v souladu se stanoven\u00FDm z\u00E1m\u011Brem. V\u00FDstupem projektu je 6 publikac\u00ED, dal\u0161\u00ED 3 p\u0159ipravovan\u00E9, 10 refer\u00E1t\u016F na mezin\u00E1rodn\u00EDch konferenc\u00EDch, \u00FAdaje dolo\u017Eeny. Finan\u010Dn\u00ED p\u0159esuny zd\u016Fvodn\u011Bny. Postavena unik\u00E1tn\u00ED aparatura pro THz spektroskopii"@cs . . . . . "http://www.isvav.cz/projectDetail.do?rowId=GA202/98/P022"^^ . "\u010Casov\u011B rozli\u0161en\u00E1 terahertzov\u00E1 spektroskopie tenk\u00FDch feroelektrick\u00FDch vrstev a GaAs/AlGaAs heterostruktur" . . "The goal of this project is to introduce the time-resolved terahertz spectroscopy method in our laboratory and take its advantages to study polar excitations in the far infrared and millimeter spectral range. The method will be used for the investigationof thin ferroelectric films (study of soft polar transverse phonons near phase transitions) and on GaAs/AlGaAs heterostructures (study of quantum oscillations of carrier wave packets: Bloch oscillations, exciton beats). The technique uses a femtosecond Ti:Sapphire laser and it consists in generation and phase-sensitive detection of ultrashort (sub-ps) long-wavelength pulses (frequencies 10 GHz - 3 THz). The study of thin ferroelectric films is based on the measurements of the THz pulse waveform changesinduces by the complex transmission function of the film. The advantage of this method comparing to the conventional Fourier IR spectroscopy is the possibility of phase sensitive detection which allows to calculate both real and imaginary part of the com"@en . . "4"^^ . "0"^^ . "Podstatou projektu je zaveden\u00ED metody impulsn\u00ED terahertzov\u00E9 spektroskopie v na\u0161\u00ED laborato\u0159i a jej\u00ED vyu\u017Eit\u00ED ke studiu excitac\u00ED spadaj\u00EDc\u00EDch do frekven\u010Dn\u00EDho oboru dalek\u00E9 infra\u010Derven\u00E9 a milimetrov\u00E9 oblasti. Metoda bude konkr\u00E9tn\u011B aplikov\u00E1na na tenk\u00E9 feroelektrick\u00E9 vrstvy (studium m\u011Bkk\u00FDch transvers\u00E1ln\u00EDch pol\u00E1rn\u00EDch fonon\u016F v okol\u00ED f\u00E1zov\u00FDch p\u0159echod\u016F) a na heterostuktury GaAs/GaAs (studium kvantov\u00FDch oscilac\u00ED vlnov\u00FDch bal\u00EDk\u016F nositel\u016F n\u00E1boje, Blochovy oscilace, excitonov\u00E9 r\u00E1zy). V experimentech se vyu\u017EijeTi:saf\u00EDrov\u00E9ho laseru jako\u017Eto zdroje fs puls\u016F ve spektr\u00E1ln\u00ED oblasti okolo 800 nm. Metoda spo\u010D\u00EDv\u00E1 v generaci a f\u00E1zov\u011B citliv\u00E9 detekci velmi kr\u00E1tk\u00FDch (sub-ps) dlouhovlnn\u00FDch puls\u016F (o frekvenci 10 GHz - 3 THz). P\u0159i studiu tenk\u00FDch feroelektrick\u00FDch vrstev se bude m\u011B\u0159it zm\u011Bna \u010Dasov\u00E9ho profilu THz puls\u016F po pr\u016Fchodu tenkou vrstvou. V\u00FDhodou t\u00E9to metody oproti konven\u010Dn\u00ED fourrierovsk\u00E9 infra\u010Derven\u00E9 spektroskopii je pr\u00E1v\u011B mo\u017Enost f\u00E1zov\u011B citliv\u00E9 detekce, d\u00EDky kter\u00E9 lze vypo\u010D\u00EDtat re\u00E1lnou i imagin\u00E1rn\u00ED slo\u017Eku komplexn\u00ED" . . "4"^^ . "1"^^ .