Studies of laser resonators and beam propagation using fast transform methods
Laser resonator design and optical beam propagation are very interesting problems today. This dissertation presents a number of contributions to these topics. In order to develop an efficient method for the numerical computation of optical diffraction effects, the quasi Fast Hankel Transform (FHT) algorithm is improved and tested for beam propagation calculations in cylindrical coordinates. Accuracy criteria are established and relationships between optical Fresnel number and numerical sampling parameters are found. Extensive application of this propagation scheme to resonator eigenmode analysis is carried out. One example is the diffraction-biased unstable resonator, a new concept which has potential use in the laser angular rotation sensor. In a separate purely analytical study, the analytic solutions of the perturbed Gaussian modes of an unbalanced antiresonant ring laser cavity are also studied by perturbation theory. This resonator has the apparently unique property of exhibiting transverse mode selection even with infinite diameters for all mirrors and apertures. Finally, we have investigated second harmonic generation (SHG) in non-linear materials with beam diffraction, pump depletion, and arbitrary beam profiles all taken into consideration. Numerical calculations are done with the use of the FHT in cylindrical coordinates, and Fast Fourier Transforms in rectangular coordinates. Theory was confirmed with an experiment using an unstable-resonator Nd:YAG output beam pumping a KDP crystal.
- OSTI ID:
- 6946435
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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