Enhanced Bandwidth in Radiation Sensors Operating at the Fundamental Temperature Fluctuation Noise Limit

Area of Science:

• Physics
• Materials Science
• Nanotechnology

Background:

• Temperature-based radiation detectors are crucial for long-wavelength detection.
• These detectors typically face bandwidth limitations, with performance degrading at higher frequencies due to thermal response time cutoffs.

Purpose of the Study:

• To overcome the inherent bandwidth limitations of temperature-based radiation detectors.
• To demonstrate enhanced detection bandwidth by operating at the fundamental temperature fluctuation noise limit.

Main Methods:

• Utilized a nanomechanical sensor engineered for frequency stability limited by fundamental temperature fluctuations.
• Operated the sensor over an unprecedentedly large bandwidth of 54 Hz.

Main Results:

• Achieved bandwidth enhancement, breaking the typical frequency limitations.
• Sensor performance remained within a factor of 3 of peak detectivity (D*T = 7.4 × 10^9 cm Hz^1/2 W^-1) over the extended bandwidth.
• Demonstrated this enhancement despite a thermal cutoff frequency 30 times lower (1.8 Hz).

Conclusions:

• Nanomechanical sensors operating at their fundamental temperature fluctuation noise limit can overcome traditional bandwidth limitations.
• Derived theoretical expressions predicting bandwidth enhancement for resonator-based sensors using closed-loop frequency tracking.