Zhang Yudong

33 W quasi-continuous-wave narrow-band sodium D-2a laser by sum-frequency generation in LBO

We demonstrate an all-solid quasi-continuous-wave (QCW) narrow-band source tunable to sodium D-2a line at 589.159 nm. The source is based on sum-frequency mixing between lasers at 1064 nm and 1319 nm in a LBO crystal. The 1064 nm and 1319 nm lasers are produced from two diode side-pumped Nd:YAG master oscillator power amplifier (MOPA) laser systems, respectively. A 33 W output of 589 nm laser is obtained with beam quality factor M-2 = 1.25, frequency stability better than +/- 0.2 GHz and linewidth less than 0.44 GHz. A prototype 589 nm laser system is assembled, and a sodium laser guided star has been successfully observed in the field test.

Effects of Different Zernike Terms on Optical Quality and Vision of Human Eyes

The visual quality of human eyes is much restricted by high-order aberrations as well as low-order aberrations (defocus and astigmatism), but each term of high-order aberrations contributes differently. The visual acuity and contrast of the image on the retina can be gained by inducing aberrations to each term of high orders. Based on an adaptive optics system, the visual acuity of four subjects is tested by inducing aberrations to each Zernike term after correcting all the aberrations of the subjects. Zernike terms near the center of the Zernike tree affect visual quality more than those near the edge both theoretically and experimentally, and 0.1-mu m aberration of these terms can clearly degrade the optical quality and vision. The results suggest that correcting the terms near the center of Zernike tree can improve the visual quality effectively in practice.

Ocular aberrations manipulation with adaptive optics and its application

自适应光学技术能够对波前像差进行实时测量及调控。1997年，该技术被首次成功地应用于活体人眼像差的调控，并获得了接近衍射极限的高分辨力视网膜视细胞图像和传统低阶像差矫正无法达到的“超视力”。随后自适应光学技术在眼科学研究中得到迅速发展。就研究内容来看，该领域主要包括视网膜高分辨力成像和人眼像差操控与视功能研究两大方向。美国Rochester大学Williams教授和加利福利亚大学Roorda教授于2011年分别对视网膜高分辨力成像和人眼像差操控与视功能研究方向的研究作了非常全面的综述。1997年，光电所在国内率先开展人眼自适应光学技术及其应用研究，本文在简单介绍人眼自适应光学系统原理的基础上，报道了光电所在该领域近五年的主要研究进展。