Adaptive optics imaging system based on a high-resolution liquid crystal on silicon device

Quanquan Mu,Dayu Li,Zhaoliang Cao,Lifa Hu,Li Xuan

doi:10.1364/oe.14.008013

Abstract

An adaptive optics imaging system is introduced in this paper. A high resolution liquid crystal on silicon (LCOS) device was used as a phase only wave front corrector instead of a conversional deformable mirror. The wave front aberration was detected by a Shack-Hartmann (SH) wave front sensor, which has lambda/100 rms wave front measurement accuracy. Under this construction 0.09lambda (lambda=0.6328microm) Peak to Valley correction precision was reached. Further more, some low frequency hot convection turbulence induced by an electric iron was compensated in real time at the same precision. The Modulation Transfer Function (MTF) of this system was also measured before and after wave front correction. Under the active correction of LCOS, the system reached the diffraction limited resolution approximately 65l p/mm on the horizontal direction. All of this showed the ability of using this device in high resolution, low temporal turbulence imaging system, such as retinal imaging, to improve the resolution performance.

Highlights

Most available adaptive optics systems consist of a deformable mirror, which is very expensive and difficult to fabricate
An adaptive optics imaging system is introduced in this paper
The wavefront aberration was detected by a Shack-Hartmann (SH) wavefront sensor, which has a wavefront measurement accuracy of λ/100 rms (λ = 0.6328 μm)

Summary

Introduction

Most available adaptive optics systems consist of a deformable mirror, which is very expensive and difficult to fabricate. Some LC SLM-based adaptive optics systems have had very effective performance in astronomy [10], and they exhibit the enormous potential for using liquid crystal devices in wavefront correction. Because the liquid crystal on silicon (LCOS) device has a small pixel pitch and high pixel density, it can get a modulation depth of more than 2 π in a wide wavelength range (from 400 nm to 700 nm). Such a system is beneficial to imaging operations with a small area, high precision, large modulation depth, and high resolution, such as retinal imaging. We intend to investigate its possible use in improving the imaging definition

Experimental setup

Wavefront correction under low disturbance

Wavefront correction under dynamic turbulence

Conclusion