A holographic wavefront sensor inclusive of a multiplexed hologram that can reconstruct one or more diffracted beams from a single object or input beam onto a distant image plane. The position of the reconstructed beams on the distant image plane indicates the relative amounts of different aberrations present in the input beam. Optical and computer realization of the employed hologram are accomplished along with sensor configurations in simple and more complex uses.

An improved ophthalmic instrument including a wavefront sensor that estimates aberrations in reflections of the light formed as a spot image on the retina of the human eye. The wavefront sensor includes a beam splitter operably disposed between a lenslet array and multiple imaging devices. The lenslet array forms a first array of spots, and the multiple imaging devices capture multiple images of the first array of spots for use in estimating the aberrations of the eye in a manner that minimizes the adverse effects of eye movement on the accuracy of such estimates. The beam splitter preferably comprises a prismatic beam splitter that splits light incident thereto into multiple arms. The multiple image devices may capture at least a first image of the first array of spots at best focus and a second image of the first array of spots near best focus for use in dynamically identifying sub-arrays (pixel areas) of the Hartmann spot imaging device (e.g., the imaging device that will be used for the determination of Hartmann spot positions) that avoid dot crossover for a particular wavefront measurement. An additional imaging device may be operably coupled to the beam splitter to capture at least one image of the pupil image plane of the lenslet array for use in identifying fiducial points therein (or for automatically identifying lenslet centers therein), thereby minimizing the adverse effects of eye movement on the accuracy of such measurements.

A wavefront measuring system and method for detecting phase aberrations in wavefronts that are reflected from, transmitted through or internally reflected within objects sought to be measured, e.g., optics systems, the human eye, etc. includes placing a reticle in the path of a return beam from the object, and placing a detector at a diffraction pattern self-imaging plane relative to the reticle. The diffraction pattern is analyzed and results in a model of the wavefront phase characteristics. A set of known polynomials is fitted to the wavefront phase gradient to obtain polynomial coefficients that describe aberrations in the object or within the wavefront source being measured.

A system and method for focusing electromagnetic energy on a moving target. Generally, the inventive system sends a pilot beam to a target and analyzes a return wavefront to ascertain data with respect to any distortions and other phase and/or amplitude information in the wavefront. This information is then used to pre-distort an output beam by so that it is focused on the target by the intervening distortions. In an illustrative embodiment, the pilot beam is provided by a beacon laser mounted off-axis with respect to the output beam. The reflected wavefront is received through a gimbaled telescope. Energy received by the telescope is detected and processed to ascertain wavefront aberrations therein. This data is used to predistort a deformable mirror to create an output beam which is the phase conjugate of the received wavefront. In a first alternative embodiment, a nonlinear optical phase-conjugate mirror is employed to generate the required wavefront-reversed replica of the received wavefront. The system further includes an arrangement for modulating the output beam to confuse the target. In a second alternative embodiment, the system is adapted to examine atmospheric distortions of starlight to predistort the output beam. The alternative embodiment offers a faster response time and a lower susceptibility to detection.

An apparatus for determining the objective refraction of a patient's eye includes a transparent window and a wavefront measurement device that determines aberrations in a return beam from the patient's eye after the beam passes through a corrective test lens in the apparatus. The wavefront measurement device outputs an instant display representative of the quality of vision afforded the patient through the test lens. The display can be a representation of a Snellen chart, convoluted with the optical characteristics of the patient's vision, an overall quality of vision scale or the optical contrast function, all based on the wavefront measurements of the patient's eye. The examiner may use the display information to conduct a refraction examination and other vision tests without the subjective response from the patient.