Micromachined optical tunable filter for domestic gas sensors

Alause, H.; Grasdepot, F.; Malzac, J. P.; Knap, Wouter; Hermann, J.

doi:10.1016/s0925-4005(97)00139-1

Cited by 13 publications

(4 citation statements)

References 3 publications

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“…Usually, the gap width is tuned to achieve the desired wavelength and operate the device as a wavelength selector or monochromator. Tunable devices with a gap width that is variable by electrostatic actuation via electrodes on movable micromachined parts (Figure 2b) have been reported by several groups (46)(47)(48)(49)(50). Such devices operate preferably in the near-infrared region at wavelengths longer than 1 μm, where silicon substrates become transparent.…”

Section: R Ementioning

confidence: 83%

“…Such devices operate preferably in the near-infrared region at wavelengths longer than 1 μm, where silicon substrates become transparent. Typical applications include gas sensors and remote gas sensing in plumes (48)(49)(50)(51)(52)(53). Characteristic absorption wavelengths are 4.7 μm for CO, 4.2 μm for CO 2 , and 3.3 μm for methane or hydrocarbons (infrared region, molecular vibrations).…”

Section: R Ementioning

confidence: 99%

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Adaptive Microsensor Systems

Gutierrez‐Osuna

Hierlemann

2010

Annual Rev. Anal. Chem.

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We provide a broad review of approaches for developing chemosensor systems whose operating parameters can adapt in response to environmental changes or application needs. Adaptation may take place at the instrumentation level (e.g., tunable sensors) and at the data-analysis level (e.g., adaptive classifiers). We discuss several strategies that provide tunability at the device level: modulation of internal sensing parameters, such as frequencies and operation voltages; variation of external parameters, such as exposure times and catalysts; and development of compact microanalysis systems with multiple tuning options. At the data-analysis level, we consider adaptive filters for change, interference, and drift rejection; pattern classifiers that can adapt to changes in the statistical properties of training data; and active-sensing techniques that can tune sensing parameters in real time. We conclude with a discussion of future opportunities for adaptive sensing in wireless distributed sensor systems.

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Section: R Ementioning

confidence: 83%

Section: R Ementioning

confidence: 99%

Adaptive Microsensor Systems

Gutierrez‐Osuna

Hierlemann

2010

Annual Rev. Anal. Chem.

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“…O PTICAL microcavities, such as might be used as filters for pressure sensing [1]- [3], chemical detection [4] or optical communication [5]- [8] are sensitive to spectral degradation. This is particularly true for cavities in integrated arrays where process nonuniformities will cause the micromirrors that form different cavities to have slightly different alignments.…”

Section: Introductionmentioning

confidence: 99%

Spatial-Mode Analysis of Micromachined Optical Cavities Using Electrothermal Mirror Actuation

Liu

Talghader

2006

J. Microelectromech. Syst.

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The performance of optical microcavities is limited by spectral degradation resulting from thermal deformation and fabrication imperfections. In this paper, we study the spatial-mode properties of micromirror optical cavities with respect to commonly seen aberrations. Electrothermal actuation is used to slightly adjust the shape and position of micromirrors and study the effects this has on the spatial-mode structure of the cavity spectrum. The shapes of the micromirrors are changed using Joule heating with thermal expansion deformation. Significant differences in mirror tilt, curvature, and astigmatism are measured, but the tilt has by far the biggest impact on cavity finesse and resolution. We demonstrate that unwanted higher order spatial modes can be suppressed electrically and an amplitude reduction for the higher order modes of over 60% has been obtained with a tuning current of 5.5 mA. A fundamental mode finesse of approximately 60 is maintained throughout tuning. These tunable cavities have great potential in applications using cavity arrays or requiring dynamic mode control.[1559]

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“…2 Microoptical Fabry-Perot devices have been pursued for various applications, with the main emphasis on wavelength selector units for use in optical communications systems. In addition, Alause et al reported a micromachined optical tunable filter for use as a domestic gas sensor for the detection of gases having absorption bands between 2 and 8 m. 5 They varied the voltage applied to the filter from 0 to 19 V and observed gap varia-tions from 2 to 0.7 m. Similarly, Melendez et al have presented high-resolution gas sensors using Fabry-Perot resonators with working wavelength range of 4 to 5 m. 6 Harper et al have shown the application of a miniature micromachined Fabry-Perot interferometer to optical fiber WDM systems. In addition, Alause et al reported a micromachined optical tunable filter for use as a domestic gas sensor for the detection of gases having absorption bands between 2 and 8 m. 5 They varied the voltage applied to the filter from 0 to 19 V and observed gap varia-tions from 2 to 0.7 m. Similarly, Melendez et al have presented high-resolution gas sensors using Fabry-Perot resonators with working wavelength range of 4 to 5 m. 6 Harper et al have shown the application of a miniature micromachined Fabry-Perot interferometer to optical fiber WDM systems.…”

Section: Introductionmentioning

confidence: 99%

Bulk micromachining of a MEMS tunable Fabry-Perot interferometer: effect of residual silicon on device performance

Srivastava

Shenoy

Forrest

et al. 2004

J. Micro/Nanolith. MEMS MOEMS

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A broadband tunable filter for the infrared spectral region is desired for use as a wavelength selective element in a miniature absorption spectrometer. We present the design, fabrication, packaging, and characterization of a bulk micromachined Fabry-Perot interferometer (FPI) for meeting this need. A novel approach to fabricate a MEMSbased tunable resonant cavity using two separate wafers bonded using a ''lock-and-key'' spacer design is outlined, with the goal of realizing electrostatically actuated membranes from films predeposited on base substrates. This ability could enable the pursuit of MEMS devices without in-house chemical vapor deposition (CVD) capability, after overcoming the shortcomings of bulk micromachining. The FPI device was designed with a planar structure comprising two face-to-face bonded chips of overall lateral dimension 10ϫ10 mm with deflection regions of 2ϫ2 mm. The device employs electrostatic actuation to tune the output wavelength, for which finite element modeling predicted low (Ͻ1 V) actuation voltages for movement of the membrane. Experimental results from device testing (mechanical) were found to differ from the theoretical predictions, primarily due to fabrication issues. Specifically, the device performance was found to be greatly influenced by the amount of residual silicon on the wafer chip following inductively coupled plasma (ICP) backside etching, with high voltages (ϳ30 times higher than modeled) required for actuation of the device. Through a combination of modeling and experimental measurements, it is demonstrated that the ability to produce MEMS devices by releasing membranes from films predeposited on substrates is highly susceptible to error in etching and packaging.

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Micromachined optical tunable filter for domestic gas sensors

Cited by 13 publications

References 3 publications

Adaptive Microsensor Systems

Adaptive Microsensor Systems

Spatial-Mode Analysis of Micromachined Optical Cavities Using Electrothermal Mirror Actuation

Bulk micromachining of a MEMS tunable Fabry-Perot interferometer: effect of residual silicon on device performance

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