Hartmann–Shack wavefront sensing without a lenslet array using a digital micromirror device

Abstract

The common Hartmann-Shack wavefront sensor makes use of a lenslet array to sample in-parallel optical wavefronts. Here, we introduce a Hartmann-Shack wavefront sensor that employs a digital micromirror device in combination with a single lens for serial sampling by scanning. Sensing is analyzed numerically and validated experimentally using a deformable mirror operated in closed-loop adaptive optics with a conventional Hartmann-Shack wavefront sensor, as well as with a set of ophthalmic trial lenses, to generate controllable amounts of monochromatic aberrations. The new sensor is free of crosstalk and can potentially operate at kilohertz speed. It offers a reconfigurable aperture that can exclude unwanted parts of the wavefront.

Differential detection of retinal directionality

“…This would retain the symmetry of the imaging system while still allow calculation of differentials. This could be realized with a spatial light modulator or a digital micromirror device that could sample the pupil at will [40]. This would have increased flexibility without additional image degradation beyond the reduction in sampled pupil size.…”

Measuring Ocular Aberrations Sequentially Using a Digital Micromirror Device

“…A wavefront sensor based on sequential scanning of a reflective cell with a DMD (V-7001 VIS, Vialux, Chemnitz, Germany) is used to measure ocular aberrations. The system, which is described in detail in [13], has been adapted for real-time aberration sensing of the human eye. A schematic of the setup can be seen in Figure 1.…”

“…These translations were used to calculate the Zernike coefficients from which the least-square wavefront reconstruction was performed. The procedure of this method is explained in detail in [13]. For 5 × 5 DMD sampling, the PSF corresponding to DMD cells illuminated across more than 50% of their area were analyzed and used for the reconstruction, while for 10 × 10 sampling, only those 100% illuminated were considered.…”

“…As the need to determine ocular aberrations has become increasingly important for personalized refractive corrections using custom LASIK [10], and for the understanding of a number of refractive problems ranging from keratoconus [11] to increased high myopia [12], establishing a wavefront sensing technique that provides a high dynamic range, resolution, and high speed suitable for the human eye is crucial. Digital micromirror devices (DMDs) can operate at speeds in the 10′s of kHz range, while sequential scanning provides a large dynamic range due to the lack of a lenslet array; therefore, avoiding the appearance of cross-talk, as recently proposed by the authors in a DMD-WFS [13]. Additionally, DMDs have recently been used for ophthalmic applications in retinal imaging [14] and psychophysical measurements [15].…”

A High-Speed, Wavelength Invariant, Single-Pixel Wavefront Sensor With a Digital Micromirror Device

“…Methods to do so include ray tracing schemes, intensity measurements at several positions along the beam path, pyramid sensors, interferometric approaches, computational approaches, the use of non-linear optics, computer generated holograms (CGHs), meta-materials and polarimetry [8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Perhaps the most well-known is the Shack-Hartmann wavefront sensor [22,23]. Its popularity stems from the simplicity of the configuration as well as the fact that the output can easily be used to drive an adaptive optical loop for wavefront correction.…”