The ultrashort chirped pulse amplification (CPA) laser technology opens the path to high intensities of 10^21 W/cm² and above in the laser focus. Such intensities allow laser-matter interaction in the relativistic intensity regime. Direct diode-pumped ultrashort solid-state lasers combine high-energy, high-power and efficient amplification together, which are the main advantages compared to flashlamp-pumped high-energy laser systems based on titanium-doped sapphire. Development within recent years in the field of laser diodes makes them more and more attractive in terms of total costs, compactness and lifetime. This work is dedicated to the Petawatt, ENergy-Efficient Laser for Optical Plasma Experiments (PENELOPE) project, a fully and directly diode-pumped laser system under development at the Helmholtz–Zentrum Dresden – Rossendorf (HZDR), aiming at 150 fs long pulses with energies of up to 150 J at repetition rates of up to 1 Hz. The focus of this thesis lies on the spectral and width manipulation of the front-end amplifiers, trivalent ytterbium-doped calcium fluoride (Yb3+:CaF2) as gain material as well as the pump source for the final two main amplifiers of the PENELOPE laser system. Here, all crucial design parameters were investigated and a further successful scaling of the laser system to its target values was shown. Gain narrowing is the dominant process for spectral bandwidth reduction during the amplification at the high-gain front-end amplifiers. Active or passive spectral gain control filter can be used to counteract this effect. A pulse duration of 121 fs was achieved by using a passive spectral attenuation inside a regenerative amplifier, which corresponds to an improvement by a factor of almost 2 compared to the start of this work. A proof-of-concept experiment showed the capability of the pre-shaping approach. A spectral bandwidth of 20nm was transferred through the first multipass amplifier at a total gain of 300. Finally, the predicted output spectrum calculated by a numerical model of the final amplifier stages was in a good agreement with the experimental results. The spectroscopic properties of Yb3+:CaF2 matches the constraints for ultrashort laser pulse amplification and direct diode pumping. Pumping close to the zero phonon line at 976nm is preferable compared to 940nm as the pump intensity saturation is significantly lower. A broad gain cross section of up to 50nm is achievable for typical inversion levels. Furthermore, moderate cryogenic temperatures (above 200K) can be used to improve the amplification performance of Yb3+:CaF2. The optical quality of the doped crystals currently available on the market is sufficient to build amplifiers in the hundred joule range. The designed pump source for the last two amplifiers is based on two side pumping in a double pass configuration. However, this concept requires the necessity of brightness conservation for the installed laser diodes. Therefore, a fully relay imaging setup (4f optical system) along the optical path from the stacks to the gain material including the global beam homogenization was developed in a novel approach. Beside these major parts the amplifier architecture and relay imaging telescopes as well as temporal intensity contrast (TIC) was investigated. An all reflective concept for the relay imaging amplifiers and telescopes was selected, which results in several advantages especially an achromatic behavior and low B-Integral. The TIC of the front-end was improved, as the pre- and postpulses due to the plane-parallel active-mirror was eliminated by wedging the gain medium.

The aim of this thesis is to investigate how digital activism is conducted on Twitter, particularly in relation to the dialogues and demands for Europe’s green economic recovery plan from COVID-19. It seeks to analyse the communication made using #GreenRecovery on Twitter by various actors over the period of May to June 2020, guided by the theory of public sphere and social movement and literature on digital activism, hashtag activism, Corporate Social Responsibility (CSR) and Corporate Political Activity (CPA) using a qualitative and quantitative content analysis.By analysing the frequency patterns of tweets and by uncovering the different types of communication, this paper sheds light on the users involved as well as the issue frames and mobilisation strategies that were visible in the #GreenRecovery discourse . Results of this study demonstrate that #GreenRecovery is used by varying actors on Twitter such as individuals, social movements, businesses and others. Furthermore, the hashtag has been used to raise awareness, communicate particular information, mobilize action and also employ assertion as dominant digital spectator activity. Tweets with #GreenRecovery was primarily framed towards the need for a redesign of the economy, indicating demands for changes in policies by targeting accounts of political actors from the EU Commission. It is further implied that during the discourse, #GreenRecovery acted as a structural signifier as a response to the leaked proposal of the Recovery Plan demonstrating that it has the potential to create hashtag communities.

Bakgrund och problemdiskussion: Att erhålla ett godkänt resultat på auktorisationsprovet och därmed bli auktoriserad revisor utgör ett långsiktigt mål och milstople för många revisionsmedarbetare. I Sverige motsvarar denna titel en kvalitetsstämpel på att revisorn har den kompetens som krävs för att enligt nationell lagstiftning utöva professionen. I dagens föränderliga samhälle möter revisionsyrket nya krav, dilemman och reformer för att säkerställa att branschen balanserar yrkets attraktion med kompetens. Studien ämnar således att utforska de komplexiteter och utmaningar som är förknippade med att uppnå denna eftertraktade titel med hänsyn till branschens föränderliga krav och den föränderliga utbildningsmiljön som råder för framtida revisorer. Speciellt med tanke på att det är cirka 40 procent som i dagsläget erhåller ett underkänt resultat. Syfte: Syftet med studien är att analysera eventuella mönster, trender och hinder som påverkar möjligheterna till auktorisation. Metod: Studien bygger på en deduktiv flermetodsstudie där befintlig teori har använts för att härleda hypoteser som sedan testas statistiskt utifrån data tilldelad av Revisorsinspektionen. För att skapa ytterligare förståelse för resultaten från den kvantitativa delstudien utförs även semistrukturerade intervjuer som syftar till att inkludera tentandernas egna uppfattningar och erfarenheter. På så sätt tillåts fördjupande inslag för att vidga insikterna och generera en helhetlig bild över tentandernas potential att erhålla ett godkänt resultat.  Slutsats: Utifrån teorier om profession, kompetensutveckling, genus och socialt kapital visar resultaten att byråtillhörighet, ålder och provtillfälle har en avgörande påverkan på om tentanden lyckas på auktorisationsprovet. Arbetslivserfarenhet från Big-4-byråer anses vara betydande för framgång på provet, vilket medför att provets bredd och relevans i förhållande till verkliga typsituationer kan ifrågasättas. Dessutom poängteras det även hur individuella faktorer har ett inflytande på utfallet. Vidare visar resultatet hur RIFS 2018:1's införande har haft en negativ påverkan på erhållna poäng och möjligheten till ett godkänt resultat. Trots detta anses yrkets roll som profession inte hotad i och med provets bibehållande svårighetsgrad såväl som att arbetslivserfarenhet uppfattas som det främsta medlet för kunskapsinsamling. / Background and Problem: The pursuit of achieving a passing result on the certification exam, and thereby becoming a certified public accountant, is a long-term goal and milestone for many audit employees. In Sweden, this title represents a benchmark of quality assurance that the auditor has the competence required to practice the profession according to national legislation. In today's changing society, the audit profession faces new demands, dilemmas, and reforms to ensure that the industry balances professional attractiveness with competence. The study thus aims to explore the complexities and challenges associated with achieving this coveted title, taking into account the changing demands of the industry and the changing educational environment prevailing for future accountants, especially considering that it is approximately 40 percent who currently receive a failing result.  Purpose: The purpose of the study is to analyze possible patterns, trends, and obstacles that affect the possibilities for authorization.  Method: The study is based on a mixed-methods research with a deductive approach, where existing theory has been used to derive hypotheses that are then tested statistcally based on data provided by Revisorsinspektionen. In order to gain further understanding of the results from the quantitative sub-study, semi-structured interviews are also conducted with the aim of incorporating the examinees' own perceptions and experiences. With this approach, deeper insights are allowed to broaden and generate a holistic picture of the examinees' potential to obtain a passing result.  Conclusion: Based on theories about profession, competence development, gender and social capital, the results show that agency affiliation, age, and the time of examination significantly influence whether the examinee suceeds in the CPA-exam or not. Work experience from Big-4 agencies is considered significant for success on the exam, which disputes the exam´s relevance to real-life situations. Additionally, results demonstrate how the introduction of RIFS 2018:1 has negatively impacted the points obtained and the possibility of achieving a passing result. Despite this, the auditing profession is not considered threatened due to the CPA-exam's maintained level of difficulty, as well as the perception that practical expertise is the primary means of acquiring knowledge.

The accounting profession continually has problems with hiring and keeping qualified staff; and many accounting scandals have shown a lack of ethical behavior on the part of Certified Public Accountants (CPA). This suggest a misfit between those in the profession and the ethics that the profession strives towards. Research has shown that the congruity of personal values with organizational values, person-organization fit (P-O fit), is an important factor in the hiring, socialization, and retention of employees. In addition, ethical behavior has been found related to P-O fit. Accounting educators have been called upon to address these problems by inculcating accounting students with the values of the accounting profession. This research firstly reports on the results of a comparison of the personal values of upper level accounting students in Georgia with the personal values of CPA leaders in Georgia. Personal value priorities were measured with the Rokeach Value Survey (RVS). The findings indicated that these samples of Georgia CPA leaders (N = 193) and accounting students (N = 516) significantly differed in the priority given to 24 of the 36 (66.7%) RVS values. This result suggests a lack of P-O fit between accounting students and the accounting profession. Secondly, this research reports on the effectiveness of two education interventions designed to improve the P-O fit of accounting students: a Curriculum Modification Intervention and a Value Self-Confrontation (VSC) Intervention. These education interventions were delivered online as part of the content of two distance learning classes on accounting ethics. The curriculum of both classes were augmented with content aimed at increasing the priority given to the value of courageous. The two classes were designated as either Group 1 or Group 2. Group 1 received only the Curriculum Modification Intervention. Group 2 received both the Curriculum Modification Intervention and the VSC Intervention, which was targeted at increasing the priority given to the four values of capable, courageous. honest, and responsible—values related to the Code of Professional Conduct and Bylaws (2012) of the American Institute of Certified Public Accountants. The results indicated that Group 1, from the beginning to the end of class (short-term value change), did not increase the priority given to courageous. Thus, the stand-alone Curriculum Modification Intervention did not result in the desired effect. Group 2, on the other hand, did increase the short-term priority given to all four of the targeted values. Moreover, Group 2 increased the long-term priority given to two of the four targeted values: capable and courageous. The higher priority given to these values at the end of class persisted for 15-16 weeks. The effect sizes indicated practical significance. These results suggest that the VSC Intervention was effective at inducing both short-term and long-term value change in the priority given to values of importance to the ethics of the accounting profession. These findings have implications for CPA firms, specifically with regard to hiring ethically “fitting” staff and fostering an ethical culture in accounting firms. The results of this research also provide input that may be helpful in improving accounting pedagogy, especially the pedagogy of accounting ethics education and distance education. Key words: person-organization fit, P-O fit, CPA firm turnover, personal values, value change, value self-confrontation, VSC, Rokeach Value Survey, RVS, Certified Public Accountant, CPA, ethics education, accounting students, online education, distance learning. / Business Management / D.B.L.

The main aim of the thesis is to analyse the national reverse charge in the building industry with a focus on the effect on the selected provider. However, the aim of this study is not only to outline an influence and effect on the business sphere, but make such a methodical basis, which would improve awareness not only in the business sphere but also in the general public. In the theoretical part, important terms are defined and a fundamental theory with a focus on the national reverse charge in the building industry is introduced. In the practical part, the actual application of this system is described in the form of the common opinions and principles, analysis assessing the influence of this system on cash flow, requisitions, tax liability and other factors. The end of this study is created by gathered results and findings of the effect on the selected business partner.

本研究的主要目的是探討會計師事務所審計人員對衍生性金融商品(DFI)的財務報導與查核能力，並分析可能影響此項能力的因素。另一目的則是希望探討審計人員對財務會計準則公報第二十七號的意見及看法，以及對這號公報的瞭解程度。本研究以問卷為蒐集資料的工具，在139份回收的問卷中，只有24位審計人員不知道什麼是DFI，約有九成的審計人員認為查核含有從事DFI交易公司之財務報表之審體審計風險較沒有從事此類交易的公司高。造成審計人員對DFI財務報導的認知程度差異的原因，經統計檢定後，有下列幾項： （1） 審計人員在事務所擔任的職位， （2） 審計人員認定衍生性金融商品的能力，以及 （3） 審計人員是否曾經查過衍生性金融商品。 造成審計人員對DFI財務報導查核能力差異的原因經統計檢定後，有下 列幾項： （1） 事務所的規模， （2） 審計人員之最高學歷， （3） 審計人員是否已取得會計師資格， （4） 審計人員在事務所擔任的職位， （5） 審計人員認定衍生性金融商品的能力， （6） 審計人員對衍生性金融商品的熟悉程度，以及 （7） 審計人員是否曾經查過衍生性金融商品。 審計人員是否曾查核過DFI並不會影響其對第二十七號公報的熟悉程度。此外，約三成的審計人員認為「各類商品之財務風險」與「商品之公平市價」是其依照此號公報查核DFI時最難決定之項目。至於審計人員如何驗證客戶在財務報表上所揭露關於DFI的公平價值，約各有三成的審計人員取得之方式為「採用公開市場之成交價」、「向銀行詢價」。 值得注意的是，在瞭解第二十七號公報的審計人員當中，只有約半數認為依照第二十七號公報揭露DFI，能幫助閱表者評估風險；同樣地，也只有半數的審計人員認為第二十七號公報能對他們在查核DFI時提供更明確的指引。審計人員是否曾經查核過DFI不會影響他們對這兩個問題的看法。 / In this study, the author investigated the degree of auditors' cognition and audit ability on derivative financial instruments (DFI) in Taiwan and he studied some factors that might affect these abilities. Besides, the author also investigated auditors' opinions of Statement of Financial Accounting Standard No. 27 in ROC. The author used questionnaire as a tool in gathering data. Factors that might affect auditors' cognition of DFI are as follows: (1) The current job position of auditors. (2) The auditors' abilities to recognize DFI. (3) The auditors' experiences of auditing DFI. Factors that might affect auditors' audit ability of DFI are as follows: (1) Firm size. (2) The highest education auditors received. (3) Whether they have got CPA license. (4) The current job position of auditors. (5) The auditors' abilities to recognize DFI. (6) The auditors' experiences of auditing DFI. (7) The extent of auditors' familiarity toward DFI. Auditors' opinions of Statement of Financial Accounting Standard No. 27 in ROC can be concluded as follows: (1) Only half of the auditors who understand this statement think it can help them to audit DFI related disclosures. (2) Whether auditors have audited DFI doesn't affect the extent of auditors' familiarity toward DFI. (3) "Financial risk" and " fair value of DFI" are two of the most difficult items to decide when auditors audit DFI.

從美國的安隆(Enron)、世界通訊(WorldCom)、全錄公司(Xerox)，義大利的帕瑪列(Parmalat)，相關專業機構包括安達信(Arthur Andersen)、美林證券(Merrill Lynch)、花旗銀行(Citibank)；到臺灣的太電、博達、訊碟….等，一連串上市公司及專業機構爆發財務弊案，投資大眾人心惶惶。會計師受託查核公司財務報表並對報表表示意見，在健全資本市場的任務中擔任極為重要的角色，社會大眾對會計師之職責賦予相當大的期待，但弊案連續爆發卻使會計師的專業遭受嚴重質疑。因此，一般而言，弊案爆發或會計師受主管機關懲處後，會計師姓名就會與「審計品質不佳」劃上等號，因此先前由被懲處之會計師所簽證之其他受查公司，不論有無類似弊病，都會被人以放大鏡來觀察。然而，究竟懲戒制度實施結果是否合乎立法初衷而提升會計師之審計品質？被懲戒之會計師是否真代表其審計品質較低？則無法得知，此即為本研究欲探討的議題。 本研究以裁決性應計數報導幅度大小將會計師之審計品質予以量化，並參考Nagy(2005)的研究模式，將樣本分為會計師更換前後期，並對獨立及配對樣本作分析，以探討因懲戒而更換會計師對審計品質之影響。研究結果發現，在更換會計師的前提下，即便懲戒更換會計師並未能顯著抑制公司對於正向裁決性應計數之報導幅度，卻能避免一般情況下更換會計師對審計品質所造成的負面情形。另外，研究結果顯示，會計師長任期(6年以上)審計品質較高；會計師短任期(2年以下)且更動過於頻繁的情況下審計品質較低。在懲戒程度與審計品質之關係方面，研究結果顯示，會計師懲戒輕重程度未與會計師審計品質高低一致；而受警告及申誡懲戒但未被客戶更換之會計師在懲戒後次期，傾向調低公司盈餘，查核工作態度變保守，但審計品質並未提升。再者，本研究發現，受懲戒而更換會計師之效果大致而言並不受客戶談判籌碼的影響。最後，就單一時點(PC=0)的會計師審計品質而言，會計師被懲戒與否其審計品質並未有顯著不同；然將樣本群組進行分析後，發現有三位至四位被懲戒會計師其審計品質顯著不佳，而被懲戒之會計師中，即使差異未達顯著，卻是幾乎每2人就有1人審計品質較一般會計師低，因此懲戒制度基本上具適當性。基於以上發現，本研究肯定會計師懲戒制度對審計品質提升之效用。 總而言之，懲戒制度在於避免專業人士怠忽其職、違規行事而侵害大眾利益，不僅處分已違法之會計師，對於其他會計師亦有警惕之意味，因此實有其存在之必要。然其制度設立之適當性，可由懲戒制度實施案例之相關研究略知一二，主管機關應參考學者研究，找出目前會計師懲戒制度效用不彰的癥結點，進行改善，以增進大眾利益，符合社會期待。 / rom USA to Taiwan, lots of frauds upset investors in recent years. Accountants are asked to express their opinions toward the financial reports, and have played an important role in the capital market. Investors rely on what accountants assure to make decisions. However, with so many frauds broke up, accountants’ professionalism and assurance quality are being questioned. Sanctions may be due to the profession’s self-regulation system or based on judgment of the regulators’ administrative power. Nevertheless, does the sanction system actually protect or enhance accountants’ audit quality as it is originally set up for？Do the punished accountants really provide lower quality on the audit they perform? The answers to these questions are unknown, and they are the subject of this study. The study quantifies accountants’ audit quality by the amount of discretionary accruals of the financial statements of their audit clients. Referring to the research model of Nagy(2005), we classify samples into two periods, i.e., before and after changing accountants. Moreover, the study matches each observation sample with a paired sample and analyzes whether the sanction has affected the audit quality. The study concludes that the sanction system is appropriate basically. The results approve that the accountant sanction system in Taiwan is somewhat effective on improving audit quality. In short, the purpose of CPA sanction is to enforce professional conduct on all members of the profession. It not only punishes the accountants that break laws, but also alerts others. Therefore, the sanction system is necessary. The regulators should refer to these findings and solve the problems that diminish the effect of the sanction system. After all, the sanction system may be able to offer investors a more matured investment environment and achieve their expectations.

本研究使用台灣的營利事業所得稅資料並且以托賓自我選擇模型來檢視租稅逃漏、稅務選查與會計師稅務簽證三者的關聯性。實證結果顯示台灣的稅務機關在查核預算的限制之下會進行有系統的稅務選查程序；進一步來說，使用會計師稅務簽證的企業組織較不易被稅務機關選查。此外，企業組織的重要特徵如規模、財務狀況、獲利能力以及會計師稅務簽證的使用與否將會影響企業組織的租稅逃漏額。最後，我們發現會計師稅務簽證的使用對於租稅逃漏的影響會隨著公司的規模大小而改變，營收大於一億的企業組織若使用會計師稅務簽證將會比未使用會計師稅務簽證的企業組織有更高的逃漏稅額。因此，我們認為與會計師稅務簽證相關的政策法規可能需要重新評估是否適切。 / This study uses the business income tax dada in Taiwan to empirically examine the relationships between audit selection, tax evasion, and the usage of CPA-attestation. Tobit model with self-selection is used in this study. Empirical results provide evidence that tax agencies in Taiwan employ a systematic audit selection process, subject to the constraints of audit budgets. Additionally, firms using CPA-attestation are less likely to be selected for audit. The results also provide evidence that some important characteristics of firms, such as size, financial position, profitability, and the usage of CPA-attestation, may influence the amount of tax evasion. Finally, we find that the effect of CPA-attestation on tax evasion may vary with different sizes of firms using CPA-attestation. Hence, the policy and tax regulations associated with the usage of CPA-attestation may need to be re-evaluated.

Made available in DSpace on 2016-06-02T19:39:42Z (GMT). No. of bitstreams: 1 5853.pdf: 4186685 bytes, checksum: fb2ecf17572a25d7181b7a21be25147a (MD5) Previous issue date: 2014-02-24 / Financiadora de Estudos e Projetos / This dissertation aims to investigate the performance of the Self Evaluation Commission (CPA) in conjunction with the processes of institutional self-evaluation, for both make use of a case study in UFSCar that the division of institutional assessment were investigated with four undergraduate courses face of the institution, all of the São Carlos campus. To this end, this study was guided from the qualitative, so research made use of desk research, semistructured interviews, the literature review and the online questionnaire closed. Documentary research was analyzed in the legislation of public policies for higher education evaluation, the period from 1996 to 2008, and the internal regulations of the institution. For bibliographic bibliometrics, which allowed analyzing 54 studies among theses, dissertations and articles in national and international researchers who investigate thematic educational assessment. Participated in semi-structured interviews of the following actors: coordinator or deputy coordinator of each course, a former member of CPA/UFSCar, and a former member of the Organizing Committee of the Project Evaluation of Undergraduate Teaching UFSCar. Finally, the closed online questionnaire was administered to students regularly enrolled in the penultimate and last year, the teacher who teaches discipline penultimate and last, and the administrative technician investigated each course. The results achieved through the collection of data showed that there was a poor articulation of the outcomes of institutional self-evaluation that occurs in courses with the actions taken by the CPA and the Management UFSCar. To sensitize the academic community to participate in the processes of institutional assessment would need to enhance information management within the IES, so that the CPA can be known to then be recognized. The little time to build the self-assessment report on the institution does not provide time for reflection and discussion with the community. There were times that the regulatory review predominated in the institution, but there were those that prevailed in the critical evaluation in daily practice, it became evident in two courses investigated. It was found that the construction of an evaluation design is a contentious field, as there are, within the institution, social actors who want to review the ranking and classification, as there are those who want the formative and emancipatory. / Esta Dissertação de Mestrado tem o objetivo de investigar a atuação da Comissão Própria de Avaliação (CPA) em articulação com os processos de autoavaliação institucional. Para tanto fez uso de um estudo de caso na UFSCar em que foi investigada a articulação da avaliação institucional em quatro cursos presenciais de graduação da instituição, todos do campus de São Carlos. Para tal, o presente estudo orientou-se a partir da pesquisa qualitativa, assim, fezse uso da pesquisa documental, da entrevista semiestruturada, do levantamento bibliográfico e do questionário fechado online. Na pesquisa documental foi analisada a legislação das políticas públicas para avaliação da educação superior, do período de 1996 a 2008, e as regulamentações internas da instituição. Para o levantamento bibliográfico foi utilizada a bibliometria, o que possibilitou analisar 54 trabalhos entre teses, dissertações e artigos de pesquisadores nacionais e internacionais que investigam a temática avaliação educacional. Das entrevistas semiestruturadas participaram os seguintes atores: coordenador ou vicecoordenador de cada curso; um ex-membro da CPA/UFSCar; e um ex-membro da Comissão Organizadora do Projeto de Avaliação do Ensino de Graduação UFSCar. Por fim, o questionário fechado online foi aplicado aos discentes regularmente matrículados no penúltimo e no último ano; aos docentes que lecionam disciplina no penúltino e no último ano; e ao técnico administrativo de cada curso investigado. Os resultados alcançados por meio da coleta de dados demostraram que houve uma fraca articulação dos resultados da autoavaliação institucional que ocorre nos cursos com as ações desenvolvidas pela CPA e pela Gestão da UFSCar. Para sensibilizar a comunidade acadêmica a participar dos processos de avaliação institucional, seria necessário intensificar a gestão da informação dentro da IES, para que a CPA possa ser conhecida para, então, ser reconhecida. O pouco tempo para construção do relatório de autoavaliação institucional não propicia momentos de reflexão e de discussão com a comunidade. Houve momentos em que a avaliação regulatória predominou na instituição, contudo houve aqueles em que prevaleceu a avaliação emancipatória nas práticas cotidianas, evidenciando isso em dois cursos investigados. Constatou-se que a construção de uma concepção de avaliação é um campo conflituoso, pois há, dentro da instituição, atores sociais que querem a avaliação para o ranqueamento e para a classificação, como há aqueles que querem a avaliação formativa e emancipatória.

The ultrashort chirped pulse amplification (CPA) laser technology opens the path to high intensities of 10^21 W/cm² and above in the laser focus. Such intensities allow laser-matter interaction in the relativistic intensity regime. Direct diode-pumped ultrashort solid-state lasers combine high-energy, high-power and efficient amplification together, which are the main advantages compared to flashlamp-pumped high-energy laser systems based on titanium-doped sapphire. Development within recent years in the field of laser diodes makes them more and more attractive in terms of total costs, compactness and lifetime. This work is dedicated to the Petawatt, ENergy-Efficient Laser for Optical Plasma Experiments (PENELOPE) project, a fully and directly diode-pumped laser system under development at the Helmholtz–Zentrum Dresden – Rossendorf (HZDR), aiming at 150 fs long pulses with energies of up to 150 J at repetition rates of up to 1 Hz. The focus of this thesis lies on the spectral and width manipulation of the front-end amplifiers, trivalent ytterbium-doped calcium fluoride (Yb3+:CaF2) as gain material as well as the pump source for the final two main amplifiers of the PENELOPE laser system. Here, all crucial design parameters were investigated and a further successful scaling of the laser system to its target values was shown. Gain narrowing is the dominant process for spectral bandwidth reduction during the amplification at the high-gain front-end amplifiers. Active or passive spectral gain control filter can be used to counteract this effect. A pulse duration of 121 fs was achieved by using a passive spectral attenuation inside a regenerative amplifier, which corresponds to an improvement by a factor of almost 2 compared to the start of this work. A proof-of-concept experiment showed the capability of the pre-shaping approach. A spectral bandwidth of 20nm was transferred through the first multipass amplifier at a total gain of 300. Finally, the predicted output spectrum calculated by a numerical model of the final amplifier stages was in a good agreement with the experimental results. The spectroscopic properties of Yb3+:CaF2 matches the constraints for ultrashort laser pulse amplification and direct diode pumping. Pumping close to the zero phonon line at 976nm is preferable compared to 940nm as the pump intensity saturation is significantly lower. A broad gain cross section of up to 50nm is achievable for typical inversion levels. Furthermore, moderate cryogenic temperatures (above 200K) can be used to improve the amplification performance of Yb3+:CaF2. The optical quality of the doped crystals currently available on the market is sufficient to build amplifiers in the hundred joule range. The designed pump source for the last two amplifiers is based on two side pumping in a double pass configuration. However, this concept requires the necessity of brightness conservation for the installed laser diodes. Therefore, a fully relay imaging setup (4f optical system) along the optical path from the stacks to the gain material including the global beam homogenization was developed in a novel approach. Beside these major parts the amplifier architecture and relay imaging telescopes as well as temporal intensity contrast (TIC) was investigated. An all reflective concept for the relay imaging amplifiers and telescopes was selected, which results in several advantages especially an achromatic behavior and low B-Integral. The TIC of the front-end was improved, as the pre- and postpulses due to the plane-parallel active-mirror was eliminated by wedging the gain medium.