3,846 research outputs found
Cavity Optomechanical Magnetometer
A cavity optomechanical magnetometer is demonstrated where the magnetic field
induced expansion of a magnetostrictive material is transduced onto the
physical structure of a highly compliant optical microresonator. The resulting
motion is read out optically with ultra-high sensitivity. Detecting the
magnetostrictive deformation of Terfenol-D with a toroidal whispering gallery
mode (TWGM) resonator a peak sensitivity of 400 nT/Hz^.5 was achieved with
theoretical modelling predicting that sensitivities of up to 500 fT/Hz^.5 may
be possible. This chip-based magnetometer combines high-sensitivity and large
dynamic range with small size and room temperature operation
Photonic Sensors Based on Integrated Ring Resonators
This thesis investigates the application of integrated ring resonators to different sensing applications. The sensors proposed here rely on the principle of optical whispering gallery mode (WGM) resonance shifts of the resonators. Three distinct sensing applications are investigated to demonstrate the concept: a photonic seismometer, an evanescent field sensor, and a zero-drift Doppler velocimeter. These concepts can be helpful in developing lightweight, compact, and highly sensitive sensors. Successful implementation of these sensors could potentially address sensing requirements for both space and Earth-bound applications. The feasibility of this class of sensors is assessed for seismic, proximity, and vibrational measurements
Z-Axis Optomechanical Accelerometer
We demonstrate a z-axis accelerometer which uses waveguided light to sense
proof mass displacement. The accelerometer consists of two stacked rings (one
fixed and one suspended above it) forming an optical ring resonator. As the
upper ring moves due to z-axis acceleration, the effective refractive index
changes, changing the optical path length and therefore the resonant frequency
of the optical mode. The optical transmission changes with acceleration when
the laser is biased on the side of the optical resonance. This silicon nitride
"Cavity-enhanced OptoMechanical Accelerometer" (COMA) has a sensitivity of 22
percent-per-g optical modulation for our highest optical quality factor (Q_o)
devicesComment: Published in Proceedings of the 25th IEEE International Conference on
Micro Electro Mechanical Systems (MEMS 2012), Paris, France, January 29 - Feb
2, 2012, pp. 615-61
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