Fig. 1. Structure of Herriott gas cell

Fig. 2. Light spot distribution in gas cell

Fig. 3. Change of spot diameter of incident light on mirror

Fig. 4. Increase of mirror distance causes spot rotation

Fig. 5. Change of mirror distance results in misalignment between exit spot and hole

Fig. 6. Mirror M₂ is tilted

Fig. 7. Mirror tilt causes light spot to emerge from mirror edge

Fig. 8. Mirror tilt causes light spot to emerge from incident hole

Fig. 9. Eccentricity and tilt of mirror M₂

Fig. 10. Relationship between mirror distance and power utilization

Fig. 11. Relationship between mirror relative distance and power utilization

Fig. 12. Simulation results of mirror distance error

Fig. 13. Relationship between mirror tilt around x axis and power utilization

Fig. 14. Relationship between mirror tilt around y axis and power utilization

Fig. 15. Simulation results of mirror tilt error around x axis

Fig. 16. Simulation results of mirror tilt error around y axis

Fig. 17. Relationship between mirror x-axis eccentricity and power utilization

Fig. 18. Relationship between mirror y-axis eccentricity and power utilization

Fig. 19. Simulation results of x-axis eccentricity error of mirror

Fig. 20. Simulation results of y-axis eccentricity error of mirror