Simulation and validation of a prototype swing arm profilometer for measuring extremely large telescope...

Area of Science:

• Optical engineering
• Astronomy instrumentation
• Metrology

Background:

• Extremely Large Telescope (ELT) designs rely on large, segmented primary mirrors.
• Metrology of aspherical, off-axis mirror segments presents significant challenges, including global form accuracy, mid-spatial frequency control, and precise matching of base-radius and conic constants.

Purpose of the Study:

• To propose and validate a swing arm profilometer (SAP) as an independent metrology technique for ELT mirror segments.
• To assess the feasibility of SAP for verifying critical optical parameters of segmented mirrors.

Main Methods:

• Development and simulation of a swing arm profilometer (SAP) specifically for aspherical, off-axis mirror segments.
• Experimental verification of simulation results using a prototype SAP instrument.

Main Results:

• Simulations demonstrated the potential of SAP for accurate metrology of mirror segment form and parameters.
• Prototype testing successfully validated the simulation results, confirming SAP's efficacy.

Conclusions:

• The swing arm profilometer (SAP) provides a viable, interferometry-independent method for ELT mirror segment metrology.
• SAP technology can ensure the high precision required for next-generation astronomical observatories.