Advanced MEMS Membrane
At the heart of Optoacoustics’ extraordinary fiber optic sensor is our ultra sensitive reflective membrane, a product of advanced micro-electro mechanical systems (MEMS) technology. The active area of this extremely thin membrane is composed of low stress silicon nitride, engineered with numerous circular corrugations to increase its sensitivity. At its center is a tiny gold dot, which serves as the surface that receives and reflects light.
During operation, this gold dot is the pinpoint for all measurements, making it possible to adjust both sensitivity and signal-to-noise response by dynamically changing the intensity of light transmitted by the source LED.
Here also, since no electronic components are used to produce a signal, electromagnetic interference (EMI) and radio frequency interference (RFI) are not a factor in sensor performance.
Membrane Linear Response
This proprietary membrane experiences a smooth linear response with a dynamic range of 100 dB. Optoacoustics has designed each of the following critical membrane parameters to optimize sensor performance:
- Membrane layer materials (Young modulus)
- Membrane layer residual stress
- Membrane layer thickness
- Membrane size
- Corrugation profile and depth
- Gold dot reflectivity to IR
- Gold dot residual stress