Optical microphone hears ultrasound

Fischer, Balthasar

doi:10.1038/nphoton.2016.95

Cited by 128 publications

(49 citation statements)

References 8 publications

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“…5 were used to compute the sensitivity as a function of the surrounding refractive index change, knowing that the refractive index of air is linked to the atmospheric pressure and to the temperature as follows3435:…”

Section: Resultsmentioning

confidence: 99%

Ultrasensitive plasmonic sensing in air using optical fibre spectral combs

et al. 2016

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Surface plasmon polaritons (SPP) can be excited on metal-coated optical fibres, enabling the accurate monitoring of refractive index changes. Configurations reported so far mainly operate in liquids but not in air because of a mismatch between permittivities of guided light modes and the surrounding medium. Here we demonstrate a plasmonic optical fibre platform that overcomes this limitation. The underpinning of our work is a grating architecture—a gold-coated highly tilted Bragg grating—that excites a spectral comb of narrowband-cladding modes with effective indices near 1.0 and below. Using conventional spectral interrogation, we measure shifts of the SPP-matched resonances in response to static atmospheric pressure changes. A dynamic experiment conducted using a laser lined-up with an SPP-matched resonance demonstrates the ability to detect an acoustic wave with a resolution of 10−8 refractive index unit (RIU). We believe that this configuration opens research directions for highly sensitive plasmonic sensing in gas.

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Section: Resultsmentioning

confidence: 99%

Ultrasensitive plasmonic sensing in air using optical fibre spectral combs

et al. 2016

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“…Such a countermeasure may also minimize changes in the refractive index of the sample gas being directly caused by sound. The effect that pressure waves also cause a change in refractive index is exploited by optical microphones using an interferometer to detect sound [18,19]. Due to the lack of any resonance the modulation (detection) frequency can be freely selected.…”

Section: Discussionmentioning

confidence: 99%

2f-wavelength modulation Fabry-Perot photothermal interferometry

Waclawek¹,

Bauer²,

Moser³

et al. 2016

Opt. Express

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Trace gas detection was performed by the principle of photothermal interferometry using a Fabry-Perot interferometer combined with wavelength modulation and second harmonic detection. The sensor employed a compact, low-volume gas cell in an overall robust set-up without the use of any moveable part. A quantum cascade laser was used as powerful mid-infrared excitation source to induce refractive index changes in the sample, whereas a near-infrared laser diode served as probe source to monitor the photo-induced variations. The functional principle of the selective sensor was investigated by detection of sulfur dioxide. For the targeted absorption band centered at 1379.78 cm^-1 a 1 σ minimum detection limit of about 1 parts per million by volume was achieved. The work demonstrates high potential for further sensor miniaturization down to a sample volume of only a few mm³. Limitations and possible improvements of the sensor regarding sensitivity are discussed.

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“…The Fabry-Parot cavity formed between fiber tip and cantilever will change its length under acoustic waves and be measured by fast demodulated white-light interferometry, then it will be converted into electrical signals. In more advanced sensing mechanisms, direct coupling between acoustic waves and light are performed to achieve high sensitivity and low noise detection [74,75]. Table 1 has given a comparison among MEMS microphone types.…”

Section: Mems Acoustic Sensormentioning

confidence: 99%

Development Trends and Perspectives of Future Sensors and MEMS/NEMS

et al. 2019

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With the fast development of the fifth-generation cellular network technology (5G), the future sensors and microelectromechanical systems (MEMS)/nanoelectromechanical systems (NEMS) are presenting a more and more critical role to provide information in our daily life. This review paper introduces the development trends and perspectives of the future sensors and MEMS/NEMS. Starting from the issues of the MEMS fabrication, we introduced typical MEMS sensors for their applications in the Internet of Things (IoTs), such as MEMS physical sensor, MEMS acoustic sensor, and MEMS gas sensor. Toward the trends in intelligence and less power consumption, MEMS components including MEMS/NEMS switch, piezoelectric micromachined ultrasonic transducer (PMUT), and MEMS energy harvesting were investigated to assist the future sensors, such as event-based or almost zero-power. Furthermore, MEMS rigid substrate toward NEMS flexible-based for flexibility and interface was discussed as another important development trend for next-generation wearable or multi-functional sensors. Around the issues about the big data and human-machine realization for human beings’ manipulation, artificial intelligence (AI) and virtual reality (VR) technologies were finally realized using sensor nodes and its wave identification as future trends for various scenarios.

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Optical microphone hears ultrasound

Cited by 128 publications

References 8 publications

Ultrasensitive plasmonic sensing in air using optical fibre spectral combs

Ultrasensitive plasmonic sensing in air using optical fibre spectral combs

2f-wavelength modulation Fabry-Perot photothermal interferometry

Development Trends and Perspectives of Future Sensors and MEMS/NEMS

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