Novel methods of intracavity beam shaping

Methods of shaping laser beams within the laser resonator are studied. The simplest form of shaping is the spatial mode generation inherent in the laser cavity due to the geometry of the resonator in conjunction with gain to compensate for roundtrip losses, such as diffraction and output coupling. Typically the fundamental mode or multimode behavior is exhibited from such configurations. Passive mode shaping can be accomplished by introducing static amplitude or phase masks. An example of an amplitude mask is provided in order to generate a higher-order spatial mode. Active mode shaping can be accomplished by altering the optical pump distribution. This case is studied experimentally with a diode-end-pumped Nd:YVO₄ laser and compared to modeling of expected Hermite-Gaussian mode generation. Active mode shaping allows the preferred mode distribution to be altered in real time. Additional shaping can be done following the resonator to modify a Hermite-Gaussian mode into a psuedo-Laguerre-Gaussian mode. This work also shows that using the coherent propagation method of Gaussian beam decomposition is capable of modeling and describing intracavity beam shaping.