Note: innovative demodulation scheme for coherent detectors in cosmic microwave background experiments

Area of Science:

• Cosmology
• Astrophysics
• Detector Physics

Background:

• Cosmic Microwave Background (CMB) polarization experiments require precise detection of faint signals.
• Non-white noise, particularly narrow-band interference, poses a significant challenge in CMB data analysis.
• Current demodulation techniques offer limited suppression of such noise.

Purpose of the Study:

• To introduce an advanced demodulation scheme for coherent detectors in CMB experiments.
• To enhance the suppression of narrow-band noise.
• To improve the overall noise performance of CMB detectors.

Main Methods:

• Developed a novel demodulation technique based on three-point numerical differentiation.
• Compared the performance of the new scheme against traditional two-point differentiation methods.
• Validated the method using a real-world detector in an experimental setting.

Main Results:

• The proposed three-point differentiation demodulation acts as a second-order high-pass filter, offering superior noise suppression compared to the first-order filter of traditional methods.
• Demonstrated significant improvements in suppressing narrow-band noise using a real detector.
• Observed an enhancement in the detector's noise floor performance.

Conclusions:

• The innovative three-point differentiation demodulation scheme effectively reduces narrow-band noise in CMB detectors.
• This advancement is crucial for improving the sensitivity and accuracy of future cosmic microwave background polarization experiments.
• The improved noise suppression and floor performance pave the way for more precise cosmological measurements.