Development of High Power Yb:YAG Laser for Amplifying Orbital Angular Momentum Modes and Pumping Optical Parametric Chirped Pulse Amplifiers

• Author / Creator

  Eltahlawy, Mohammed

• The applications of ultra-high power laser systems are generating growing interest in a wide variety of scientific fields. They can be used to simulate astrophysical processes and accelerate electrons and protons to MeV energies and generate KeV to MeV x-rays. Such sources can be used for taking high-resolution images of various systems from biological tissues to car engines in a relatively compact system and also can be used for cancer therapy.
  A Terawatt laser system is the basic building block for much larger facilities, so, studying a such laser system develops all the key technologies which can be then scaled to much larger systems. The key components required for a Chirped Pulse Amplification (CPA) TW laser system based on diode pumped Yb:YAG (Ytterbium doped in Yttrium Aluminum Garnet) ceramic disks will be described. A fiber based femtosecond oscillator based on the dissipative soliton technique is designed and characterized yielding pulses at 24 MHz repetition rate capable of being compressed to ~200 fs pulse duration at an average power of 200 milliwatts (mW). These pulses were stretched to 1 ns duration in a grating stretcher and amplified to the 2-3 mJ level in a regenerative amplifier. Appreciable gain narrowing occurs with an output spectrum which is ~2 nm wide centered at 1030 nm. Further amplification to the 100 mJ and 400 mJ levels is carried out utilizing slab amplifier disks, backside pumped by the diode array modules yielding 2.5 KW of pump power in 10 mm by 13 mm modules. Compression of the output pulse to 1 ps is achieved which is close to the bandwidth limit for the 1.8 nm output bandwidth measured. Modeling of the different stages of the laser system is also demonstrated in agreement with the measurements. Two different applications for the Terawatt laser system which are the generation and amplification of high power Orbital Angular Momentum (OAM) modes and the pumping of a noncollinear interaction Optical Parametric Chirped Pulse Amplifier (OPCPA) are presented. Finally, further system optimization and future directions are discussed.

• Subjects / Keywords

  • OPCPA
  • Ytterbium
  • Yb:YAG
  • OAM
  • femtosecond
  • Laser

• Graduation date

  Fall 2018

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3QV3CK7P

• License

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