Femtosecond time-resolved photoelectron spectroscopy (fsTRPES) experiments have been used to study the photoelectron energy spectra of simple molecules since the 1980’s. Analysis of these spectra provides information about the ultrafast internal conversion dynamics of the parent ions. However, ultraviolet pulses must be used for these pump-probe experiments in order to ionize the molecules. Since current solid state lasers, such as the Ti:sapphire laser, typically produce pulses centered at 800nm, it is necessary to generate UV pulses with nonlinear frequency mixing techniques. I therefore constructed an optical setup to generate the 3rd and 4th harmonics, at 266.7nm and 200nm, respectively, of a Ti:sapphire (Ti:sa) chirped-pulse amplified (CPA) laser system that produces 35fs pulses centered at 800nm. Thin Beta-Barium Borate (β-BaB2O4 or BBO) crystals were chosen to achieve a compromise between short pulse durations and reasonable conversion efficiencies, since ultrashort pulses are quite susceptible to broadening from group velocity dispersion (GVD). Output energies of around 11μJ and 230nJ were measured for the 266.7nm and 200nm pulses, respectively. The transform limits of the 3rd and 4th harmonic pulse lengths were calculated from their measured spectral widths. We found that the 266.7nm bandwidth was large enough to support sub-30fs pulses, and due to cutting at the lower-wavelength end of the 200nm spectrum, we calculated an upper limit of 38fs. The pulses were compressed with pairs of CaF2 prisms to compensate for dispersion introduced by transmissive optics. Two-photon absorption (TPA) intensity autocorrelations revealed fully compressed pulse lengths of 36 ± 2 fs and 42 ± 4 fs for the 3rd and 4th harmonics, respectively.

Femtosecond time-resolved photoelectron spectroscopy (fsTRPES) experiments have been used to study the photoelectron energy spectra of simple molecules since the 1980’s. Analysis of these spectra provides information about the ultrafast internal conversion dynamics of the parent ions. However, ultraviolet pulses must be used for these pump-probe experiments in order to ionize the molecules. Since current solid state lasers, such as the Ti:sapphire laser, typically produce pulses centered at 800nm, it is necessary to generate UV pulses with nonlinear frequency mixing techniques. I therefore constructed an optical setup to generate the 3rd and 4th harmonics, at 266.7nm and 200nm, respectively, of a Ti:sapphire (Ti:sa) chirped-pulse amplified (CPA) laser system that produces 35fs pulses centered at 800nm. Thin Beta-Barium Borate (β-BaB2O4 or BBO) crystals were chosen to achieve a compromise between short pulse durations and reasonable conversion efficiencies, since ultrashort pulses are quite susceptible to broadening from group velocity dispersion (GVD). Output energies of around 11μJ and 230nJ were measured for the 266.7nm and 200nm pulses, respectively. The transform limits of the 3rd and 4th harmonic pulse lengths were calculated from their measured spectral widths. We found that the 266.7nm bandwidth was large enough to support sub-30fs pulses, and due to cutting at the lower-wavelength end of the 200nm spectrum, we calculated an upper limit of 38fs. The pulses were compressed with pairs of CaF2 prisms to compensate for dispersion introduced by transmissive optics. Two-photon absorption (TPA) intensity autocorrelations revealed fully compressed pulse lengths of 36 ± 2 fs and 42 ± 4 fs for the 3rd and 4th harmonics, respectively.

Ultra Wideband Radio (UWB) is an upcoming alternative for wireless communications. Since the Federal Communication Commission in the USA allowed UWB for unlicensed usage in April 2002, more and more companies have started developing UWB systems. The major difference with UWB compared to other RF systems is that UWB sends information with pulses instead of using a carrier wave. The technique is from the nineteenth century and was first developed by Heinrich Hertz (1857-1894), which led to transatlantic communications 1901. This Master thesis presents a proposal of a transmitter for Ultra Wideband Radio using multiple bands. The proposed transmitter is implemented on system level in Simulink, Matlab. The frequency generation in the transmitter is also implemented at component level in a 0.13 um IBM process. The thesis begins with an introduction of UWB theory and techniques.

No description available.

No description available.

Femtosecond time-resolved photoelectron spectroscopy (fsTRPES) experiments have been used to study the photoelectron energy spectra of simple molecules since the 1980’s. Analysis of these spectra provides information about the ultrafast internal conversion dynamics of the parent ions. However, ultraviolet pulses must be used for these pump-probe experiments in order to ionize the molecules. Since current solid state lasers, such as the Ti:sapphire laser, typically produce pulses centered at 800nm, it is necessary to generate UV pulses with nonlinear frequency mixing techniques. I therefore constructed an optical setup to generate the 3rd and 4th harmonics, at 266.7nm and 200nm, respectively, of a Ti:sapphire (Ti:sa) chirped-pulse amplified (CPA) laser system that produces 35fs pulses centered at 800nm. Thin Beta-Barium Borate (β-BaB2O4 or BBO) crystals were chosen to achieve a compromise between short pulse durations and reasonable conversion efficiencies, since ultrashort pulses are quite susceptible to broadening from group velocity dispersion (GVD). Output energies of around 11μJ and 230nJ were measured for the 266.7nm and 200nm pulses, respectively. The transform limits of the 3rd and 4th harmonic pulse lengths were calculated from their measured spectral widths. We found that the 266.7nm bandwidth was large enough to support sub-30fs pulses, and due to cutting at the lower-wavelength end of the 200nm spectrum, we calculated an upper limit of 38fs. The pulses were compressed with pairs of CaF2 prisms to compensate for dispersion introduced by transmissive optics. Two-photon absorption (TPA) intensity autocorrelations revealed fully compressed pulse lengths of 36 ± 2 fs and 42 ± 4 fs for the 3rd and 4th harmonics, respectively.

Cette thèse se concentre sur la conception de circuits intégrés radio fréquence en technologie CMOS. En particulier, l’effort est axé sur les circuits pour la synthèse de fréquence (boucles à verrouillage de phase) pour les émetteurs/récepteurs. L’attention se concentre sur la conception des blocs critiques comme les oscillateurs contrôlé en tension(VCO) et les diviseurs de fréquence. La première partie de la thèse présente des directives pour la conception de VCO à résonateur LC à résistance négative et la conception d’un oscillateur en quadrature contrôlé en tension (QVCO) à 15GHz. Ce dernier représente la contribution à la réalisation d’un synthétiseur de fréquence à 15GHz en technologie CMOS 130 nm pour des applications satellites réalisé en collaboration avec Polytech’Nice (Sophia Antipolis, France). La deuxième partie de la thèse montre la contribution à la réalisation d’un synthétiseur de fréquence 60GHz en technologie CMOS 65 nm, en collaboration avec le laboratoire LAAS (Toulouse, France) pour les réseaux haut débit sans fil et à courte distance WPAN. Une attention particulière a été portée sur la conception des blocs fonctionnant des les bandes millimétriques tel que l’oscillateur et les deux premiers blocs de la chaine de division.En ce qui concerne les diviseurs de fréquence, deux topologies à injection ont été utilisées pour leur efficacité et leur basse consommation. Le prédiviseur a été conçu avec une topologie oscillateur à résonateur LC synchronisé suivi d’un oscillateur en anneau synchronisé. Le VCO a une topologie à résistance négative. Tous les circuits ci-dessus ont été réalisés et testée avec succès. / The research activities presented in this thesis are related to the design of analog CMOS Radio Frequency Integrated Circuits. In particular the effort was focused on frequency synthesizers (Phase-Locked Loop) for transceiver. This work especially deals with critical blocks such as Voltage Controlled Oscillator (VCO) and Frequency Dividers.The first part of the thesis reports the design guidelines of a negative resistance LC-tank VCO and the design of a 15GHz Quadrature Voltage Controlled Oscillator. This represents the contributions to the realizations of a Phase-Locked Loop (PLL) realization in CMOS 130 nm technology for satellite applications in collaborations with the Polytech’Nice Sophia laboratory in France. The second part of this work reports the design contribution of a 60GHz Phase-Locked Loop in 65 nm CMOS technology for Wireless Personal Area Network (WPAN) applications in collaboration with the LAAS laboratory (Toulouse, France). In particular the design efforts were devote to the blocks working at millimeter Wave (mmW) frequency such as VCO and Frequency Divider (FD). Concerning the Frequency Dividers the Injection-Locked topology was selected for the sake of its high frequency and low power characteristics. In particular the prescaler is an Injection-Locked LC-tank Frequency Divider (ILLCFD) followed by an Injection-Locked Ring Oscillator Frequency Divider (ILROFD). For the VCO the negative resistance design approach has been employed.All cited circuits have been implemented and succesfully tested.

The Terahertz (1012 Hz) region of the electromagnetic spectrum covers the frequency range from roughly 300 GHz to 10 THz, which is in between the microwave and infrared regimes. The increasing interest in the development of ultra-compact, tunable room temperature Terahertz (THz) emitters with wide-range tunability has stimulated in-depth studies of different mechanisms of THz generation in the past decade due to its various potential applications such as biomedical diagnosis, security screening, chemical identification, life sciences and very high speed wireless communication. Despite the tremendous research and development efforts, all the available state-of-the-art THz emitters suffer from either being large, complex and costly, or operating at low temperatures, lacking tunability, having a very short spectral range and a low output power. Hence, the major objective of this research was to develop simple, inexpensive, compact, room temperature THz sources with wide-range tunability. We investigated THz radiation in a hybrid optical and THz micro-ring resonators system. For the first time, we were able to satisfy the DFG phase matching condition for the above-mentioned THz range in one single device geometry by employing a modal phase matching technique and using two separately designed resonators capable of oscillating at input optical waves and generated THz waves. In chapter 6, we proposed a novel plasmonic antenna geometry – the dimer rod-tapered antenna (DRTA), where we created a hot-spot in the nanogap between the dimer arms with a very large intensity enhancement of 4.1×105 at optical resonant wavelength. Then, we investigated DFG operation in the antenna geometry by incorporating a nonlinear nanodot in the hot-spot of the antenna and achieved continuously tunable enhanced THz radiation across 0.5-10 THz range. In chapter 8, we designed a multi-metallic resonators providing an ultrasharp toroidal response at THz frequency, then fabricated and experimentally demonstrated an efficient polarization dependent plasmonic toroid switch operating at THz frequency. In summary, we have successfully designed, analytically and numerically investigated novel THz emitters with the advantages of wide range tunability, compactness, room temperature operation, fast modulation and the possibility for monolithic integration, which are the most sought after properties in the new generation THz sources.

Femtosecond time-resolved photoelectron spectroscopy (fsTRPES) experiments have been used to study the photoelectron energy spectra of simple molecules since the 1980’s. Analysis of these spectra provides information about the ultrafast internal conversion dynamics of the parent ions. However, ultraviolet pulses must be used for these pump-probe experiments in order to ionize the molecules. Since current solid state lasers, such as the Ti:sapphire laser, typically produce pulses centered at 800nm, it is necessary to generate UV pulses with nonlinear frequency mixing techniques. I therefore constructed an optical setup to generate the 3rd and 4th harmonics, at 266.7nm and 200nm, respectively, of a Ti:sapphire (Ti:sa) chirped-pulse amplified (CPA) laser system that produces 35fs pulses centered at 800nm. Thin Beta-Barium Borate (β-BaB2O4 or BBO) crystals were chosen to achieve a compromise between short pulse durations and reasonable conversion efficiencies, since ultrashort pulses are quite susceptible to broadening from group velocity dispersion (GVD). Output energies of around 11μJ and 230nJ were measured for the 266.7nm and 200nm pulses, respectively. The transform limits of the 3rd and 4th harmonic pulse lengths were calculated from their measured spectral widths. We found that the 266.7nm bandwidth was large enough to support sub-30fs pulses, and due to cutting at the lower-wavelength end of the 200nm spectrum, we calculated an upper limit of 38fs. The pulses were compressed with pairs of CaF2 prisms to compensate for dispersion introduced by transmissive optics. Two-photon absorption (TPA) intensity autocorrelations revealed fully compressed pulse lengths of 36 ± 2 fs and 42 ± 4 fs for the 3rd and 4th harmonics, respectively.

No description available.