Design And Application Study Of Low Order And Large Stroke Aberration Compensator

In optic systems with laser light source,the wavefront aberration of laser beam restricts the performance and efficiency of optic systems.Adaptive Optics(AO)can actively correct the beam aberrations of optic systems.Nowadays,AO mostly apply in laser transmission,astronomical telescopes and human eye aberration simulation,while the report of study of low order large stroke aberration compensator specifically for fiber laser beam cleanup is not much.Besides,Bimorph DM can satisfy different aperture and aberration correcting requirements of different systems by changing the electrode configuration on the bottom of PZT layer depend on its structure of whole PZT layer adhered to base layer.This paper study the fiber laser beam cleanup,analyzes aberrations of fiber laser beam,designs and manufactures 3-element unimorph DM correcting defocus aberration,and study the performance and correcting ability of DM.Firstly,this paper builds experiment system testing the beam aberration of 0.4?m~1.7?m super-continuum fiber laser,find the beam aberration at different wavelengths of 610 nm,800nm,1070 nm and 1078 nm mainly contains defocus aberration.Secondly,this paper builds 3-element unimorph DM model correcting defocus and study the influence functions of the DM model.The result shows the DM model has a deformation of 0.94?m under 100 V drive voltage and has good linearity of influence functions.Thirdly,this paper manufactures 3-element unimorph DM and builds experiment system testing the performance of DM.The PV of initial surface is about 0.73?m,and the DM has a deformation of 0.55?m under 400 V drive voltage.The frequency respond range of DM is 12 kHz.Lastly,this paper study the Zernike aberration fitting ability of DM models and correcting ability of DM device The result shows the DM model with homogeneous electrode configuration has good fitting to defocus and spherical aberration with fitting error less than 0.1;the DM model with inhomogeneous electrode configuration has good fitting to defocus but the fitting error of spherical aberration is 0.54.The DM device has good correcting to defocus with correcting error less than 0.18,but not good at spherical aberration correcting,the DM can only compensate the center area of spherical aberration.When correcting the combined aberration,the correcting error gets lower with the defocus gets more proportion.