Fig. 1. O-XYZ global coordinate system and o₁-xyz local coordinate system of off-axis aspherical mirror

Fig. 2. TDDSA surface detection system

Fig. 3. Significance and relation of different defocus coefficients

Fig. 4. Prestressed loading mechanism

Fig. 5. Zernike polynomial coefficient distribution curves of difference between mirror deformation and theoretical surface shape after multiple loading correction

Fig. 6. Process scene of stressing lapping

Fig. 7. Convergence curves of stressing processing. (a) Stressing lapping experiment; (b) Ref. [8]

Fig. 8. Mirror surface roughness measurement site

Fig. 9. Relative deformation between meniscus and reference spherical mirror with 9 points Whiffletree support

Fig. 10. Measuring of surface shape after stressing lapping using CMM

Fig. 11. Final detection results of CMM and contact TDDSA. (a) Average surface shape obtained by multiple measurements using CMM; (b) average surface profile obtained by multiple measurements of contact TDDSA; (c) residual distribution between average surface profile and theoretical off-axis aspheric surface profile obtained by multiple measurements using CMM; (d) residual distribution between average surface profile and theoretical off-axis aspheric surface profile obtained by multiple measurements of contact TDDSA

Table 1. Geometrical and material parameters of prestressed grinding experiments

Table 2. Detection results of CMM and contact type TDDSA