Photonic microharp chemical sensors

Area of Science:

• Micro-opto-mechanical systems
• Chemical sensing technology
• Photonics and interferometry

Background:

• Development of sensitive and selective chemical sensors is crucial for environmental monitoring and safety.
• Existing sensor technologies face limitations in real-time detection and analyte discrimination.
• Micro-scale devices offer advantages in sensitivity, portability, and reduced sample consumption.

Purpose of the Study:

• To introduce a new class of micro-opto-mechanical chemical sensors.
• To demonstrate the capability of a photonic microharp sensor for real-time vapor-phase analyte detection.
• To evaluate the sensor's sensitivity and discrimination abilities for various analytes.

Main Methods:

• Fabrication of a photonic microharp sensor consisting of an array of microbridges with varying lengths, each coated with a distinct sorbent polymer.
• Optical interrogation of the microharp using microcavity interferometry and photothermal actuation.
• Coupling the sensor directly to an optical fiber for signal transmission.
• Simultaneous measurement of the fundamental flexural resonant frequency of each microbridge.

Main Results:

• The photonic microharp sensor successfully detected and discriminated between various vapor-phase analytes in real-time.
• High sensitivity was achieved, with detection of Dimethyl methylphosphonate (DMMP) at concentrations as low as 17 parts per billion (ppb).
• The sensor demonstrated robust performance through simultaneous frequency measurements of the microbridge array.

Conclusions:

• The described photonic microharp represents a promising new class of micro-opto-mechanical chemical sensors.
• The sensor architecture enables sensitive, real-time detection and discrimination of chemical vapors.
• This technology holds potential for applications requiring rapid and accurate chemical analysis.