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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Construção e caracterização de um laser contínuo de titânio-safira / Construction and characterization of a CW Titanium-Saphire laser

Moraes, Flávio Campopiano Dias de 13 June 2013 (has links)
Durante este trabalho construímos e caracterizamos um laser de titânio-safira para ser utilizado em experimentos de ótica quântica e ótica não linear, no Laboratório de Manipulação Coerente de Átomos e Luz (LMCAL). Constatamos que, operando em 780nm, o laser construído têm eciência de 51%, atingindo uma potência de saída de 832mW para uma potência de bombeio de 5W, e sua largura de linha é da ordem de 0,6MHz. Analisamos também o espectro de ruído do laser e concluímos que, para frequências de análise a partir de 10MHz, a luz emitida corresponde a um estado coerente, com ruído quântico muito inferior ao dos lasers de diodo que vêm sendo utilizados no laboratório. / We built and characterized a titanium-sapphire laser to be used in quantum optics and non linear optics experiments in the Laboratory for Coherent Manipulation of Atoms and Light - LMCAL (Laboratório de Manipulação Coerente de Átomos e Luz). We veried that the laser has 51% efficiency when operating at 780nm, reaching 832mW output power for a pump power of 5W, and its linewidth is approximately 0.6MHz. We also analyzed the laser noise spectrum and found that, for analysis frequencies above 10MHz, the laser output is in a coherent state, with much lower quantum noise than the diode lasers that have been used in our laboratory.
2

Timing Issues In A Terawatt Laser System

Yilmaz, Remziye Pinar 01 September 2008 (has links) (PDF)
In the laser market, there have been various kinds of lasers designed and utilized for different purposes. As time goes on, their powers have been gradually increased from kilowatts (kW) to terawatts (TW). One of the most famous methods in laser science technology is Chirped Pulse Amplification (CPA) which enables table-top terawatt laser systems. This method provides high output power (tens of TW), very short pulse duration (few tens of femtoseconds) and large energy (mJ) for ultrafast lasers. One of the most well-known ultrafast lasers is Titanium:Sapphire laser. This thesis work concentrates on how delay a pulse generator should work so that Verdi and the oscillator pulse coincide. Moreover, by assembling a terawatt laser system, the most important issues are timing between seed pulse and pump pulse and time delays of all components of this system / autocorrelator, pump source, photodiode, Pockels cell, stretcher and dazzler were examined. This timing and the time delays were separately identified for terawatt laser systems. In this study, the aim is to attain the terawatt level output by arranging pump and seed pulses timing and the time delay on the components of the laser system setup.
3

Construção e caracterização de um laser contínuo de titânio-safira / Construction and characterization of a CW Titanium-Saphire laser

Flávio Campopiano Dias de Moraes 13 June 2013 (has links)
Durante este trabalho construímos e caracterizamos um laser de titânio-safira para ser utilizado em experimentos de ótica quântica e ótica não linear, no Laboratório de Manipulação Coerente de Átomos e Luz (LMCAL). Constatamos que, operando em 780nm, o laser construído têm eciência de 51%, atingindo uma potência de saída de 832mW para uma potência de bombeio de 5W, e sua largura de linha é da ordem de 0,6MHz. Analisamos também o espectro de ruído do laser e concluímos que, para frequências de análise a partir de 10MHz, a luz emitida corresponde a um estado coerente, com ruído quântico muito inferior ao dos lasers de diodo que vêm sendo utilizados no laboratório. / We built and characterized a titanium-sapphire laser to be used in quantum optics and non linear optics experiments in the Laboratory for Coherent Manipulation of Atoms and Light - LMCAL (Laboratório de Manipulação Coerente de Átomos e Luz). We veried that the laser has 51% efficiency when operating at 780nm, reaching 832mW output power for a pump power of 5W, and its linewidth is approximately 0.6MHz. We also analyzed the laser noise spectrum and found that, for analysis frequencies above 10MHz, the laser output is in a coherent state, with much lower quantum noise than the diode lasers that have been used in our laboratory.
4

Diagnostika impulzů Ti:Sa laseru pro generaci plazmatu / Diagnostics of Ti:Sa laser pulses for plasma generation

Weiss, Jiří January 2015 (has links)
This diploma thesis is focused on investigation of temporal characteristics of laser pulses generated by oscillator with Ti:Sapphire active laser medium. In terms of properties of laserinduced plasmas the beam quality is crucial, in particular laser pulse contrast ratio. A new prototype of third order autocorrelator was designed. Pulse contrast ratio measurement is based on sum frequency generation between pulse of fundamental wavelength and its frequency doubled replica. Dynamic range of presented autocorrelator is estimated to be up to 8×10^12 which is more than currently available commercial devices can offer.
5

Optical parametric oscillators for precision IR spectroscopy and metrology

Kovalchuk, Evgeny 21 May 2008 (has links)
In der vorliegenden Doktorarbeit wird ein Dauerstrich Optisch Parametrischer Oszillator (cw OPO) vorgestellt, der speziell für die hochauflösende Dopplerfreie Molekülspektroskopie und Metrologie entwickelt wurde. Der kontrollierte Zugang zu jeder beliebigen Wellenlänge im breiten Emissionsspektrum von OPOs wie auch das präzise Abstimmen seiner Ausgangsfrequenz über zu untersuchende molekulare und atomare Übergänge stellten lange Zeit Probleme dar, deren Lösung die Grundzielsetzung dieser Arbeit war. Das im Laufe dieser Arbeit entwickelte System hat diese Ziele vollständig erreicht, was durch verschiedene Messungen und Anwendungen demonstriert wurde. Zu diesem Zweck wurde ein neues OPO-Design mit einem Intracavity-Etalon entwickelt und aufgebaut, wobei der OPO auf dem Konzept eines einfach-resonanten cw OPOs mit resonanter Pumpwelle basiert. Die OPO-Ausgangsstrahlung zeigt sehr gute Langzeitstabilität und Spektraleigenschaften, welche durch direkte Frequenzvergleichsmessungen mit einem optischen Methan-Frequenzstandard im Infraroten bestimmt wurden. Eine Idler-Linienbreite von 12 kHz und ein Modensprung-freier Betrieb des OPOs über einen Zeitraum von einigen Tagen wurde beobachtet. Außerdem wurde gezeigt, dass ein OPO zu einer hochstabilen optischen Referenz phasengelockt und somit seine Frequenz sehr genau kontrolliert und durchgestimmt werden kann. Als erste erfolgreiche Anwendung eines OPOs in der Dopplerfreien Spektroskopie wurde ein Aufbau zur Frequenz-Modulationsspektroskopie in Methan realisiert. Weiterhin, wurde der entwickelte cw OPO mit einem femtosekunden optischen Frequenzkamm kombiniert, um eine neue Idee für eine kohärente Verbindung zwischen dem sichtbaren und dem infraroten Spektralbereich zu realisieren. Als erste Demonstration dieser Technologie wurde ein direkter absoluter Frequenzvergleich zwischen einem Jod-stabilisierten Laser bei 532 nm und einem Methan-stabilisierten Laser bei 3390 nm durchgeführt. / This thesis presents a continuous-wave optical parametric oscillator (cw OPO), specially developed for high-resolution Doppler-free molecular spectroscopy and metrology. The basic objective was to solve the long-standing problem of controlled access to any desired wavelength in the wide emission range of OPOs, including the ability to precisely tune the output frequency over the molecular and atomic transitions of interest. The system implemented during this work fully achieves these goals and its performance was demonstrated in various measurements and applications. For this aim, a new design for the OPO cavity with an intracavity etalon was implemented, extending the concept of a cw singly resonant OPO with resonated pump wave. The newly developed device demonstrates very good long-term stability and spectral properties, which were determined in direct beat frequency measurements with a methane infrared optical frequency standard. Thus, an idler radiation linewidth of 12 kHz and mode-hop-free operation of the OPO over several days were observed. Furthermore, it was shown that an OPO can be phase locked to a highly stable optical reference and thus much more precisely controlled and tuned. As the first successful application of OPOs in Doppler-free spectroscopy, a frequency modulation spectroscopy setup for detection of sub-Doppler resonances in methane was implemented. Furthermore, the developed cw OPO was integrated with a femtosecond optical frequency comb to realize a new concept for a coherent link between the visible and infrared spectral ranges. As a first demonstration of this technique, a direct absolute frequency comparison between an iodine stabilized laser at 532 nm and a methane stabilized laser at 3390 nm was performed.

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