Synthetic dispersion interferometry for relative atmospheric pressure sensing

Area of Science:

• Optics and Photonics
• Metrology
• Atmospheric Science

Background:

• Interferometry is a key technique in precision measurement.
• Previous designs of heterodyne dispersion interferometers can be complex.
• Accurate atmospheric pressure sensing is crucial for various scientific and industrial applications.

Purpose of the Study:

• To present a modified, simplified two-arm, two-color, single second harmonic generation heterodyne dispersion interferometer.
• To analyze the intrinsic system noise and drift of the modified device.
• To investigate the application of this interferometer for relative atmospheric pressure measurements.

Main Methods:

• Modification of a previously introduced interferometer by reducing optical elements.
• Implementation of digital in-phase and quadrature demodulation for phase shift retrieval from a single photodetector signal.
• Analysis of system noise and drift using Allan deviation measurements.
• Performance validation through relative pressure measurements in a pressure chamber against a piezoresistive pressure transceiver.

Main Results:

• A simplified interferometer design with reduced optical components.
• Successful retrieval of phase shift using digital demodulation from a single photodetector.
• Characterization of system noise and drift via Allan deviation.
• Demonstration of relative atmospheric pressure measurement with a deviation of less than 150 Pascals.

Conclusions:

• The modified interferometer offers a simpler and potentially more robust design.
• Digital demodulation enhances phase shift retrieval efficiency.
• The device shows promise for accurate relative atmospheric pressure measurements.