When an input Gaussian beam is improperly aligned and mode-matched to a stable optical resonator, the electric field in the resonator couples to off-axis spatial eigenmodes. We show that a translation of the input axis or a mismatch of the beam waist to the resonator waist size causes a coupling of off-axis modes which is inphase with the input field. On the other hand, a tilt of the input beam or a mismatch of the beam waist position to cavity waist position couples to these modes in quadrature phase. We also propose a method to measure these coupling coefficients and thereby provide a means to align and mode-match a resonant optical cavity in real time.
© 1984 Optical Society of America
Original Manuscript: April 12, 1984
Published: September 1, 1984
Dana Z. Anderson, "Alignment of resonant optical cavities," Appl. Opt. 23, 2944-2949 (1984)