Demonstration of real-time depth-resolved Shack-Hartmann measurements.

Shack-Hartmann wavefront sensors (SH-WFS) have little sensitivity in depth and hence are unsuitable for microscopy and are limited for retinal imaging. We demonstrate the first direct Shack-Hartmann measurement of wavefront originating from a multiple-layer target, in the presence of significant stray reflections that render a standard SH-WFS inoperable. A coherence-gate SH-WFS is implemented by adding time-domain low-coherence reflectometry gating to an SH-WFS configuration. The depth resolution is determined by the operational depth selection of the coherence gate, much narrower than the depth range of the SH-WFS. Five distinctive wavefronts are measured from five layers of a multiple-layer target. This paves the way toward depth-resolved wavefront sensing, which can significantly improve adaptive optics closed loops applied to microscopy and imaging of the retina.

[1]  Robert K. Tyson,et al.  Adaptive Optics Engineering Handbook , 1999 .

[2]  J. Girkin,et al.  Practical implementation of adaptive optics in multiphoton microscopy. , 2003, Optics express.

[3]  Claude Boccara,et al.  Thermal-light full-field optical coherence tomography in the 1.2 μm wavelength region , 2006 .

[4]  Aiko Ruprecht,et al.  Wavefront-flatness evaluation by wavefront-correlation-information-entropy method and its application for adaptive confocal microscope , 2004 .

[5]  M. Nieto-Vesperinas,et al.  Performance of a simulated-annealing algorithm for phase retrieval , 1988 .

[6]  W. Denk,et al.  Adaptive wavefront correction in two-photon microscopy using coherence-gated wavefront sensing , 2006, Proceedings of the National Academy of Sciences.

[7]  J J Miller,et al.  Aberration correction by maximizing generalized sharpness metrics. , 2003, Journal of the Optical Society of America. A, Optics, image science, and vision.

[8]  Simon Tuohy,et al.  Depth-resolved wavefront aberrations using a coherence-gated Shack-Hartmann wavefront sensor. , 2010, Optics express.

[9]  T. Wilson,et al.  Adaptive aberration correction in a confocal microscope , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[10]  A. Boccara,et al.  Thermal-light full-field optical coherence tomography. , 2002, Optics letters.

[11]  Winfried Denk,et al.  Coherence-gated wave-front sensing in strongly scattering samples. , 2004, Optics letters.

[12]  Martin J. Booth,et al.  Adaptive optics in microscopy , 2003, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[13]  Nicolas A. Roddier Atmospheric wavefront simulation using Zernike polynomials , 1990 .

[14]  T. Hebert,et al.  Adaptive optics scanning laser ophthalmoscopy. , 2002, Optics express.