High-finesse measurements at low temperatures.

Area of Science:

• Physics
• Optical Engineering
• Materials Science

Background:

• Fabry-Perot cavities are crucial for high-resolution spectroscopy and laser applications.
• Achieving high optical finesse at cryogenic temperatures presents significant engineering challenges.
• Supermirror technology is essential for minimizing optical losses in resonant cavities.

Purpose of the Study:

• To construct and characterize a Fabry-Perot cavity using high-reflectivity supermirrors.
• To investigate the performance of the cavity at cryogenic temperatures.
• To determine the optical finesse achievable and its temperature dependence.

Main Methods:

• Fabrication of a Fabry-Perot cavity utilizing high-reflectivity supermirrors.
• Operation and testing of the cavity within a cryogenic environment.
• Measurement of cavity finesse at various temperatures, including below 80 K and down to 4.2 K.

Main Results:

• The Fabry-Perot cavity was successfully operated at cryogenic temperatures.
• A maximum finesse of 19,000 was achieved below 80 K.
• The finesse remained constant at 19,000 down to the lowest tested temperature of 4.2 K.

Conclusions:

• High-reflectivity supermirrors enable the creation of high-finesse Fabry-Perot cavities for cryogenic applications.
• The demonstrated finesse is stable across a wide cryogenic temperature range.
• This work provides a robust optical cavity suitable for sensitive experiments at low temperatures.