Material and structure engineering are increasingly employed in active optical media,in this context defined as media capable of providing laser or/and optical parametric gain. For laser materials, the main aim of the engineering is to tailor the absorption and emission cross sections in order to optimise the laser performance. At the same time, the engineering also results in a collateral modification of the material’s nonlinear response. In the first part of this work, the nonlinear index of refraction is characterised for two crystallographic forms of laser-ion doped and undoped double-tungstate crystals. These laser crystals have broad gain bandwidths, in particular when doped with Yb3+. As shown in this work, the crystals also have large Kerr nonlinearities, where the values vary significantly for different chemical compositions of the crystals. The combination of a broad gain bandwidthand a high Kerr nonlinearity makes the laser-ion doped double tungstates excellent candidates to employ for the generation of ultrashort laser pulses by Kerr-lens modelocking. The second part of the work relates to the applications of engineered second-order nonlinear media, which here in particular are periodically-poled KTiOPO4 crystals. Periodic structure engineering of second-order nonlinear crystals on a submicrometre scale opens up for the realisation of novel nonlinear devices. By the use of quasi-phase matching in these structures, it is possible to efficiently downconvert a pump wave into two counterpropagating parametric waves, which leads to a device called a mirrorless optical parametric oscillator. The nonlinear response in these engineered submicrometre structures is such that the parametric wave that propagates in the opposite direction of the pump automatically has a narrow bandwidth, whereas the parametric wave that propagates with the pump essentially is a frequency-shifted replica of the pump wave. The unusual spectral properties andthe tunabilities of mirrorless optical parametric oscillators are investigated. / QC 20120330

本研究旨在探討羅狄（Richard Rorty）新實用主義中的無鏡哲學、教化作用與社會希望三者之間的關係。羅狄從一種基進的後現代觀點，對於以柏拉圖、笛卡兒、康德建立起來的哲學傳統及其當代代表–分析哲學，其中所充滿的本質主義、基礎主義、再現論、二元論等大寫哲學的鏡式本質表示不滿。 為了揭示西方傳統哲學企圖藉由心及語言再現世界嘗試的不可能性，羅狄盡力於終結此一傳統。他認為，追求大寫真理是西方傳統哲學的核心議題；形上學作為西方哲學的主要成分，是禁錮人類思想，造成心靈空乏的源頭所在。對於這種大寫真理和大寫哲學的拒斥，是當前人們必須的堅持和體認。 教化作用是羅狄所推崇的未來哲學所應採取的一個主要的自我形象，以教化作用取代以知識論為中心的系統哲學，透過拒斥本質主義，放棄以知識論為中心的邏各斯中心主義，以及反對形上學等種種反哲學傳統的進程，在追隨歷史進展的步調中，從後哲學文化的領域出發，來確立一種人類自主性教育實踐行動的激化點。羅狄以建立教化作用的教育施為，一方面描述了哲學的未來自我形象，一方面又描述了知識分子的自我形象。 羅狄對於啟蒙政治哲學的實踐層面抱持著正面的看法。羅狄認為：「只有在自由社會□，反諷人才是典型的知識分子，也唯有在自由的社會□，才能給予反諷人一種離經叛道的自由」。對於許多人來說，反諷的力量就是解構的力量，而解構是道德責任性匱乏的一個極好的標誌；反諷是對重新描述力量的自覺，是一種社會希望的重新界定和詮釋。在實踐社會希望過程中，反諷人的批判的心是從社會的邊緣指向社會的中心，但其腳步卻是從中心步向邊緣。 關鍵詞：無鏡哲學 教化作用 社會希望 自由反諷人 / This study is to find out the functions and relations among mirrorless philosophy, edification, and social hope in Rorty’s Neo-Pragmatism. Rorty’s critique of both traditional philosophy and analytic philosophy, which are derived from Plato, Descartes, and Kant, is actually based on an oppositional position of essentialism, foundationalism, representationalism, and dualism. In order to state the impossibilities of Western traditional philosophy to represent the world by mind and language, Rorty makes efforts to end Western philosophical tradition. Rorty takes it as a core issue to pursue the Truth for Western traditional philosophy. Metaphysics which impedes mankind’s thought and spirit has become the major element of Western philosophy. Edificational philosophy proposed by Rorty will be a good self-image for future philosophy. It substitutes epistemology for edification. In the postmodern conditions, Rorty uses Post-Philosophical Culture to fulfill an educational agency and create a good self-image both in philosophy and of the intellectuals. Rorty holds a positive opinion on the political enlightenment. He considers that the ironist will be the typical intellectual. He is also of the opinion that only if in a free society, would the ironist get entire freedom. For some people, the ironist power is the decostructional one, too. The ironist power will be the redefinition for man’s social hope. In those societies, the critical thinking is directed to the center from the border, and vice versa, man’s steps from the border to the center. keywords: mirrorless philosophy, edification, social hope, the liberal ironist

The present thesis concerns aspects of the interaction ofmatter in gas, liquid and solid phases, with electromagneticradiation, ranging from the optical to the X-ray region. Overthe last decade the availability of ultrashort strong laserpulses as well as of high power synchrotron sources of tunableX-ray radiation has stimulated a rapid development of newexperimental techniques which makes it possible to analysedifferent physical, chemical and biological processes inunprecedented detail. All of this urges a concomitantdevelopment of adequate theoretical language and methodscombined with simulation techniques. The first part of the thesis addresses nonlinear propagationof strong optical pulses. This study is motivated by thebreakthrough in synthesis of novel organic materials possessingprespecified nonlinear optical properties and which has led toa multitude of potential applications such as, for example, 3Dimaging and data storage, optical limiting and photodynamiccancer therapy. In order to clarify the underlying physics, astrict solution has been derived of the density matrixequations of a material aiming at an explicit treatment of itsnonlinear polarization without addressing a conventional Taylorexpansion over field amplitudes. Such a formalism is developedfor many-level molecules, allowing to solve the coupledMaxwell's and density matrix equations for the propagation of afew interacting laser pulses through a nonlinear molecularmedium. The theory presented is capable to account formulti-photon processes of an arbitrary order and for differentsaturation effects. The theory is applied to simulations oftwo- and three-photon absorption as well as to upconvertedstimulated emission of organic molecules in solvents. The second part of the thesis is devoted to resonant X-rayRaman scattering from free molecules, solutions and polymerfilms. The temporal analysis of the spectral profiles isperformed using the technique of scattering duration whichallows to select physical processes with different time scales.The slowing-down/speeding-up of the scattering by frequencydetuning provides insight in the formation of the differentparts of the scattering profile like atomic and molecularbands, resonant and vertical scattering channels, anomalousenhancement of the Stokes doubling effect. The lifetimevibrational interference (LVI), playing a crucial role inresonant scattering, is found to strongly influence thedispersion of the Auger resonances of polymers in agreementwith experiment. An almost complete quenching of the scatteringcross section by LVI is observed for the N2molecule. It is found that the interferenceelimination of the scattering amplitude gives valuableinformation on molecular geometry. The electron Doppler effectis minutely studied making use of a wave packet technique. Thesimulations show an "interference burning" of a narrow hole onthe top of the Doppler broadened profile of the Auger spectraof molecular oxygen. For the SF6molecule the Auger Doppler effect is found to besensitive to the detuning due to the scattering anisotropy. Inall of these studies the temporal language was foundconstructive and enormously helpful for understanding theunderlying physical processes. Most theoretical predictionsmade have been verified by experiments.

<p>The present thesis concerns aspects of the interaction ofmatter in gas, liquid and solid phases, with electromagneticradiation, ranging from the optical to the X-ray region. Overthe last decade the availability of ultrashort strong laserpulses as well as of high power synchrotron sources of tunableX-ray radiation has stimulated a rapid development of newexperimental techniques which makes it possible to analysedifferent physical, chemical and biological processes inunprecedented detail. All of this urges a concomitantdevelopment of adequate theoretical language and methodscombined with simulation techniques.</p><p>The first part of the thesis addresses nonlinear propagationof strong optical pulses. This study is motivated by thebreakthrough in synthesis of novel organic materials possessingprespecified nonlinear optical properties and which has led toa multitude of potential applications such as, for example, 3Dimaging and data storage, optical limiting and photodynamiccancer therapy. In order to clarify the underlying physics, astrict solution has been derived of the density matrixequations of a material aiming at an explicit treatment of itsnonlinear polarization without addressing a conventional Taylorexpansion over field amplitudes. Such a formalism is developedfor many-level molecules, allowing to solve the coupledMaxwell's and density matrix equations for the propagation of afew interacting laser pulses through a nonlinear molecularmedium. The theory presented is capable to account formulti-photon processes of an arbitrary order and for differentsaturation effects. The theory is applied to simulations oftwo- and three-photon absorption as well as to upconvertedstimulated emission of organic molecules in solvents.</p><p>The second part of the thesis is devoted to resonant X-rayRaman scattering from free molecules, solutions and polymerfilms. The temporal analysis of the spectral profiles isperformed using the technique of scattering duration whichallows to select physical processes with different time scales.The slowing-down/speeding-up of the scattering by frequencydetuning provides insight in the formation of the differentparts of the scattering profile like atomic and molecularbands, resonant and vertical scattering channels, anomalousenhancement of the Stokes doubling effect. The lifetimevibrational interference (LVI), playing a crucial role inresonant scattering, is found to strongly influence thedispersion of the Auger resonances of polymers in agreementwith experiment. An almost complete quenching of the scatteringcross section by LVI is observed for the N₂molecule. It is found that the interferenceelimination of the scattering amplitude gives valuableinformation on molecular geometry. The electron Doppler effectis minutely studied making use of a wave packet technique. Thesimulations show an "interference burning" of a narrow hole onthe top of the Doppler broadened profile of the Auger spectraof molecular oxygen. For the SF₆molecule the Auger Doppler effect is found to besensitive to the detuning due to the scattering anisotropy. Inall of these studies the temporal language was foundconstructive and enormously helpful for understanding theunderlying physical processes. Most theoretical predictionsmade have been verified by experiments.</p>