Fig. 1. Schematic diagram of PSI measurement of window transmission wavefront. (a) Cavity; (b) window information

Fig. 2. Path of test light in ideal window

Fig. 3. Path of test light in non-ideal window

Fig. 4. Noised transmitted wavefront of an ideal flat window. (a) Transmitted wavefront; (b) transmitted wavefront after multiple reflections; (c) spatial frequency spectrum of Fig.4(b); (d) enlarged view of the central area of Fig.4(c)

Fig. 5. Noised transmitted wavefront of a non-ideal window. (a) Transmitted wavefront; (b) transmitted wavefront after multiple reflections; (c) spatial frequency spectrum of Fig. 5(b); (d) enlarged view of the central area of Fig.5(c)

Fig. 6. Wavefront distribution before and after noise reduction. (a) Ideal wavefront; (b) Fig.6(a) affected by fixed patterns; (c) Fig.6(b) after noise reduction; (d) actual wavefront; (e) Fig.6(d) affected by fixed patterns; (f) Fig.6(e) after noise reduction

Fig. 7. Comparison of the 300th row of φ_w, φ_s and φ_j. (a) Ideal window; (b) actual window

Fig. 8. Window transmitted wavefront obtained by different methods. (a) Wavefront measured by LCPSI; (b) middle frequency components of Fig.8(a); (c) wavefront measured by PSI; (d) middle frequency components of Fig.8(c); (e) Fig.8(c) after noise reduction; (f) middle frequency components of Fig.8(e)