Development of stable monolithic wide-field Michelson interferometers

Area of Science:

• Optics and Photonics
• Astronomy and Astrophysics
• Materials Science

Background:

• Wide-field Michelson interferometers are vital for high-precision remote sensing and astronomical applications.
• Stable monolithic Michelson interferometers are essential for accurate radial velocity (RV) measurements in exoplanet detection.
• Interferometer stability is critically dependent on minimizing thermal distortion.

Purpose of the Study:

• To present a novel design for a stable monolithic Michelson interferometer.
• To detail the design, fabrication, and testing processes for this interferometer.
• To demonstrate its suitability for high-precision radial velocity measurements.

Main Methods:

• Thermal stress analysis to identify critical design requirements.
• Material selection based on matching coefficients of thermal expansion (CTEs) using BK7 and LAK7.
• Fabrication and rigorous testing of the monolithic interferometer.

Main Results:

• A novel monolithic interferometer design free from thermal distortion was developed.
• The interferometer exhibits a field angle of 23.8° and thermal sensitivity of -2.6×10(-6)/°C near 550 nm.
• This sensitivity corresponds to approximately 800 m/s/°C in the RV scale.

Conclusions:

• Matching CTEs is critical for interferometer stability, enabling precise RV measurements.
• The developed low-cost interferometer demonstrates high stability for long-term operation in RV instruments.
• This technology supports ongoing exoplanet searching and characterization efforts.