Unstable resonator alignment study using off-axis injection.
A brief qualitative experiment and subsequent theoretical study provide new insight concerning off-axis injection of unstable resonators. Theoretical results for aligned resonators show that the regurgitated beam intensity distribution and direction of travel are sensitive to the size, tilt, and other parameters of the injected beam, to the coherence length and number of longitudinal modes of the injecting laser, to clipping and diffraction from apertures, and to resonator length tuning. It is concluded that visual observations of output asymmetries can be used to align the resonator to some degree, but precise alignment using measurement of output asymmetries by a detector array is questionable.
Ferguson
T R
TR
Ploor
M D
MD