Quasi-monolithic heterodyne laser interferometer for inertial sensing

Area of Science:

• Optics and Photonics
• Metrology
• Instrumentation Engineering

Background:

• High-sensitivity displacement sensing is crucial for various scientific and industrial applications.
• Existing interferometers often lack compactness and are susceptible to environmental noise.

Purpose of the Study:

• To develop a compact heterodyne laser interferometer for high-sensitivity displacement sensing.
• To miniaturize the system while maintaining high performance and noise rejection.

Main Methods:

• Customized prisms and wave plates were assembled into a quasi-monolithic unit.
• A common-mode rejection scheme was implemented to mitigate environmental noise.
• Experimental tests were conducted in a vacuum environment.

Main Results:

• Achieved a displacement sensitivity of 11 picometers/root Hertz (pm/√Hz) at 100 milliHertz (mHz).
• Demonstrated a sensitivity as low as 0.6 pm/√Hz above 1 kHz.
• The prototype measures 20mm x 20mm x 10mm and weighs 4.5g.

Conclusions:

• The developed compact heterodyne laser interferometer offers exceptional displacement sensitivity.
• Its miniaturized design and noise rejection capabilities make it suitable for integration into various compact systems.
• This technology advances precision measurement capabilities in confined spaces.