Micro-cantilevers are one of the most popular Micro-Electronics-Mechanical-Sensor (MEMS).They've demonstrated in
a number of application areas such as chemical and bio-sensing. However, these devices usually need the alignment of
the cantilever with the read-out system, which can be challenging. Furthermore, it involves a bulky free-space optical
detection system. In this paper, we propose techniques to design and fabricate micro-cantilevers onto the end of standard single mode fibres using a picoseconds (ps) laser machining technique. In this way the cantilever can be aligned with the core of the fibre therefore offering stable and accurate means of optically addressing the cantilever. Low-cost optical sources and fibre coupled spectrometers are employed to interrogate the final cavity with a resolution around 15nm. Experiment show this optical fibre cantilever can be used as a displacement sensor with a dynamic range up to 7μm. Proof-of-concept experiments demonstrate that the cantilever could also be used as a temperature sensor in the range of 24-320°C with a temperature sensitivity of 0.5°C.
Micro-fabricated cantilevers have been reported recently as miniaturized, rapid response, ultrasensitive sensors elements
suitable for various chemical and bio-sensing applications. However, the alignment of the cantilever with the optical
read-out system can be challenging and typically involves a bulky free-space optical detection system. We propose using
cantilevers aligned to the core of an optical fibre during the fabrication process to address this issue.
Focussed Ion Beam (FIB) machining has been demonstrated as capable of fabricating fibre-top cantilevers. Here we
demonstrate techniques to design and fabricate micro-cantilevers using a combination of laser machining and FIB
processing to fabricate sensing cantilevers onto the end of standard and multi-core fibres (MCF). In this way the
cantilever can be aligned with the core of the fibre therefore offering stable and accurate means of optically addressing
the cantilever. Use of MCF offers the potential for a single probe capable of making multiple measurements in a
confined measurement volume, to determine multiple species of interest, or to provide background reference
measurements for example.
The optical cavity formed between the fibre and the cantilever is monitored using low-cost optical sources and fibre
coupled spectrometers to demonstrate a practical measurement system. This can readily achieve <50nm resolution using
analysis based upon recovering the free spectral range using the Fast Fourier Transform to calculate the final cavity
length.
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