Systems and methods for depth detection in laser-assisted ophthalmic procedures

An ophthalmic surgical laser system for a capsulorhexis operation is disclosed. The system comprises a laser delivery system for delivering a pulsed laser beam to a subject's eye to perform capsulorhexis, the pulsed laser beam having ultra-short pulses in femtoseconds and picoseconds range, the laser delivery system being configured to deliver the pulsed laser beam to the eye according to a vertical side cut pattern which is a cut pattern that forms a revolution located at a depth, and to move the vertical side cut pattern in the depth direction from an aqueous humor toward and into a lens capsule and a lens in the lens capsule; a mirror positioned to transmit at least a portion of collected plasma light from the eye, the plasma light being generated in the eye by the pulsed laser beam when it photoalters tissues of the eye by plasma mediated photoablation which generates a plasma; a lens positioned to focus the transmitted collected plasma light onto a detector to form spots on the detector; and a data processing system operatively coupled to the detector to determine a current location of photoablation in the subject's eye based on the spots formed by the collected plasma light focused on the detector, including determining whether the current location of photoablation is within the aqueous humor or has reached the lens capsule based on detecting an increase in intensity of the spots formed by the plasma light, the data processing system configured to determine whether, over each side cut revolution, the intensity of the spots formed by the plasma light is pulsating or constant to determine whether the current location of photoablation defined by the vertical side cut pattern is partially or entirely within the lens.