Ultra-high-bandwidth polarization interferometry and optimal quadratic phase detection.

Area of Science:

• Physics
• Plasma Physics
• Optical Interferometry

Background:

• Homodyne interferometry is a powerful technique for measuring phase changes.
• Traditional homodyne interferometry suffers from sensitivity nulls, ambiguity, and intolerance to beam power variations.
• Measuring rapid, large phase changes in dynamic environments like plasma shocks is challenging.

Purpose of the Study:

• To develop a novel homodyne interferometer and analysis method to overcome limitations of existing techniques.
• To enable high-bandwidth, high-dynamic range measurements of interferometric phase.
• To accurately measure electron density in magnetized plasma shocks with high resolution.

Main Methods:

• Utilized orthogonal polarization components within a homodyne interferometer.
• Developed an analysis method to handle large, rapid phase changes and time-dependent attenuation.
• Implemented the technique to measure electron density in a magnetized plasma shock.

Main Results:

• Successfully measured large, rapid changes in interferometric phase, in quadrature.
• Overcame major error sources including sensitivity nulls and beam power variations.
• Achieved unprecedented bandwidth and resolution in measuring plasma shock electron density.
• Revealed short-timescale electron density features not previously observed.

Conclusions:

• The novel homodyne interferometer and analysis method effectively address key limitations of traditional homodyne interferometry.
• This technique enables high-bandwidth, high-dynamic range phase measurements limited primarily by detector technology.
• The method provides a powerful new tool for studying dynamic phenomena, such as magnetized plasma shocks, with exceptional detail.