Yuhua Zhang
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Yuhua Zhang has a total of 4 co-authors. Here are the top co-authors by number of shared publications:
Austin Roorda
University of California
3 shared publications- Austin Roorda
Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley
1 shared publication Siddharth Poonja
University of California
1 shared publication- Siddharth Poonja
University of California at Berkeley, Berkeley, CA, USA
1 shared publication
Latest Publications
- 11 April 2007
- Published by Optica Publishing Group in Journal of the Optical Society of America A
- Vol. 24 (5) , 1276-1283
Photon signal detection and evaluation in the adaptive optics scanning laser ophthalmoscope
To select a suitable photodetector for an adaptive optics scanning laser ophthalmoscope (AOSLO) and evaluate its performance, we characterized the signal and noise properties in the AOSLO photon detection and derived the signal-to-noise ratio (SNR). Using the SNR as the main criterion, we chose the best detector from a selection of four photomultiplier tubes (PMTs) and three avalanche photodiodes (APDs). We conducted a comprehensive evaluation of the performance of the selected detector on our AOSLO. The study presents a practical strategy that can be used to test the photodetector for either initial evaluation or subsequent performance in in-line inspection.
- 11 April 2007
- Published by Optica Publishing Group in Journal of the Optical Society of America A
- Vol. 24 (5) , 1276-1283
Photon signal detection and evaluation in the adaptive optics scanning laser ophthalmoscope
To select a suitable photodetector for an adaptive optics scanning laser ophthalmoscope (AOSLO) and evaluate its performance, we characterized the signal and noise properties in the AOSLO photon detection and derived the signal-to-noise ratio (SNR). Using the SNR as the main criterion, we chose the best detector from a selection of four photomultiplier tubes (PMTs) and three avalanche photodiodes (APDs). We conducted a comprehensive evaluation of the performance of the selected detector on our AOSLO. The study presents a practical strategy that can be used to test the photodetector for either initial evaluation or subsequent performance in in-line inspection.
- 1 May 2006
- Published by Optica Publishing Group in Optics Letters
- Vol. 31 (9) , 1268-1270
MEMS-based adaptive optics scanning laser ophthalmoscopy
We have developed a compact, robust adaptive optics (AO) scanning laser ophthalmoscope using a microelectromechanical (MEMS) deformable mirror (DM). Facilitated with a Shack–Hartmann wavefront sensor, the MEMS-DM-based AO operates a closed-loop modal wave aberration correction for the human eye and reduces wave aberrations in most eyes to below rms. Lateral resolution is enhanced, and images reveal a clear cone mosaic near the foveal center. The significant increase in throughput allows for a confocal pinhole whose diameter is less than the Airy disc of the collection lens, thereby fully exploiting the axial resolution capabilities of the system.- 1 May 2006
- Published by Optica Publishing Group in Optics Letters
- Vol. 31 (9) , 1268-1270
MEMS-based adaptive optics scanning laser ophthalmoscopy
We have developed a compact, robust adaptive optics (AO) scanning laser ophthalmoscope using a microelectromechanical (MEMS) deformable mirror (DM). Facilitated with a Shack–Hartmann wavefront sensor, the MEMS-DM-based AO operates a closed-loop modal wave aberration correction for the human eye and reduces wave aberrations in most eyes to below rms. Lateral resolution is enhanced, and images reveal a clear cone mosaic near the foveal center. The significant increase in throughput allows for a confocal pinhole whose diameter is less than the Airy disc of the collection lens, thereby fully exploiting the axial resolution capabilities of the system.- 9 February 2006
- Published by SPIE-Intl Soc Optical Eng
- Vol. 6138
Adaptive optics scanning laser ophthalmoscope using a micro-electro-mechanical (MEMS) deformable mirror
A MEMS deformable mirror (DM)-based new generation adaptive optics scanning laser ophthalmoscope (AOSLO) has been developed for in-vivo microscopic imaging of the living human retina. With the miniaturized optical aperture of a μDMS-MultiTM MEMS DM made by Boston Micromachines Corporation (Watertown, MA), we were able to confine a compact and robust optical system to a mobile 30"×30" breadboard while keeping the system aberrations diffraction-limited over an imaging field of view up to 3×3 degrees. A customized Shack-Hartmann wavefront sensor was devised to facilitate the MEMS DM based adaptive optics (AO) system. The ocular aberration is compensated over a 6mm pupil based upon a modal wavefront correction strategy. The AO correction is done for both ingoing and outgoing paths of the scanning laser ophthalmoscope. After AO correction, the root mean square wave aberration is reduced to less than 0.1μm for most eyes. The lateral resolution is effectively enhanced and the images reveal clear cone mosaic near the foveal center. The significant increase of the throughput at the confocal pinhole allows for a confocal pinhole whose diameter is less than the Airy disc of the collection lens, thereby fully exploiting the axial resolution capabilities of the system. The MEMS DM as well as its successful application represents the most significant technological breakthrough of this new generation AOSLO.
- 9 February 2006
- Published by SPIE-Intl Soc Optical Eng
- Vol. 6138
Adaptive optics scanning laser ophthalmoscope using a micro-electro-mechanical (MEMS) deformable mirror
A MEMS deformable mirror (DM)-based new generation adaptive optics scanning laser ophthalmoscope (AOSLO) has been developed for in-vivo microscopic imaging of the living human retina. With the miniaturized optical aperture of a μDMS-MultiTM MEMS DM made by Boston Micromachines Corporation (Watertown, MA), we were able to confine a compact and robust optical system to a mobile 30"×30" breadboard while keeping the system aberrations diffraction-limited over an imaging field of view up to 3×3 degrees. A customized Shack-Hartmann wavefront sensor was devised to facilitate the MEMS DM based adaptive optics (AO) system. The ocular aberration is compensated over a 6mm pupil based upon a modal wavefront correction strategy. The AO correction is done for both ingoing and outgoing paths of the scanning laser ophthalmoscope. After AO correction, the root mean square wave aberration is reduced to less than 0.1μm for most eyes. The lateral resolution is effectively enhanced and the images reveal clear cone mosaic near the foveal center. The significant increase of the throughput at the confocal pinhole allows for a confocal pinhole whose diameter is less than the Airy disc of the collection lens, thereby fully exploiting the axial resolution capabilities of the system. The MEMS DM as well as its successful application represents the most significant technological breakthrough of this new generation AOSLO.
- Open Access
- 1 January 2006
- Published by SPIE-Intl Soc Optical Eng in Journal of Biomedical Optics
- Vol. 11 (1) , 014002-014002-5
Evaluating the lateral resolution of the adaptive optics scanning laser ophthalmoscope
We present a statistical assessment of the lateral resolution of the adaptive optics scanning laser ophthalmoscope (AOSLO). We adopt a 2-D Gaussian function to approximate the AOSLO point spread function (PSF), which is dominated by the residual wavefront aberration and characterized by the Strehl ratio. Thus, we derive the lateral resolution in the presence of residual wave aberrations, which is inversely proportional to square root of the Strehl ratio. The modeling, while not sufficient in describing the fine structure of the real PSF, demonstrates good conformance to the lateral cross section of the real PSF. With this model, the lateral resolution of our current AOSLO was computed to be 1.65 to , which agreed well with the actual result. We also reveal the relationships among the lateral resolution and other three measures of the AOSLO imaging property including the Strehl ratio, the PSF, and the root mean square (rms) of wavefront aberration.- 1 January 2006
- Published by SPIE-Intl Soc Optical Eng in Journal of Biomedical Optics
- Vol. 11 (1) , 014002-014002-5
Open AccessEvaluating the lateral resolution of the adaptive optics scanning laser ophthalmoscope
We present a statistical assessment of the lateral resolution of the adaptive optics scanning laser ophthalmoscope (AOSLO). We adopt a 2-D Gaussian function to approximate the AOSLO point spread function (PSF), which is dominated by the residual wavefront aberration and characterized by the Strehl ratio. Thus, we derive the lateral resolution in the presence of residual wave aberrations, which is inversely proportional to square root of the Strehl ratio. The modeling, while not sufficient in describing the fine structure of the real PSF, demonstrates good conformance to the lateral cross section of the real PSF. With this model, the lateral resolution of our current AOSLO was computed to be 1.65 to , which agreed well with the actual result. We also reveal the relationships among the lateral resolution and other three measures of the AOSLO imaging property including the Strehl ratio, the PSF, and the root mean square (rms) of wavefront aberration.