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Romadanov I, Raitses Y, Smolyakov A. Wavelength modulation laser-induced fluorescence for plasma characterization. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:073516. [PMID: 39012181 DOI: 10.1063/5.0187687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 06/24/2024] [Indexed: 07/17/2024]
Abstract
Laser-Induced Fluorescence (LIF) spectroscopy is an essential tool for probing ion and atom velocity distribution functions (VDFs) in complex plasmas. VDFs carry information about the kinetic properties of species that is critical for plasma characterization. Accurate interpretation of these functions is challenging due to factors such as multicomponent distributions, broadening effects, and background emissions. Our research investigates the use of Wavelength Modulation (WM) LIF to enhance the sensitivity of VDF measurements. Unlike standard Amplitude Modulation (AM) methods, WM-LIF measures the derivative of the LIF signal. This approach makes variations in VDF shape more pronounced. VDF measurements with WM-LIF were investigated with both numerical modeling and experimental measurements. The developed model enables the generation of both WM and AM signals, facilitating comparative analysis of fitting outcomes. Experiments were conducted in a weakly collisional argon plasma with magnetized electrons and non-magnetized ions. Measurements of the argon ion VDFs employed a narrow-band tunable diode laser, which scanned the 4p4D7/2-3d4F9/2 transition centered at 664.553 nm in vacuum. A lock-in amplifier detected the second harmonic WM signal, which was generated by modulating the laser wavelength with an externally controlled piezo-driven mirror of the diode laser. Our findings indicate that the WM-LIF signal is more sensitive to fitting parameters, allowing for better identification of VDF parameters such as the number of distribution components, their temperatures, and velocities. In addition, WM-LIF can serve as an independent method to verify AM measurements and is particularly beneficial in environments with substantial light noise or background emissions, such as those involving thermionic cathodes and reflective surfaces.
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Affiliation(s)
- I Romadanov
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - Y Raitses
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - A Smolyakov
- Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
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2
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Liu X, Ma Y. Tunable Diode Laser Absorption Spectroscopy Based Temperature Measurement with a Single Diode Laser Near 1.4 μm. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22166095. [PMID: 36015855 PMCID: PMC9413076 DOI: 10.3390/s22166095] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/12/2022] [Accepted: 08/12/2022] [Indexed: 05/25/2023]
Abstract
The rapidly changing and wide dynamic range of combustion temperature in scramjet engines presents a major challenge to existing test techniques. Tunable diode laser absorption spectroscopy (TDLAS) based temperature measurement has the advantages of high sensitivity, fast response, and compact structure. In this invited paper, a temperature measurement method based on the TDLAS technique with a single diode laser was demonstrated. A continuous-wave (CW), distributed feedback (DFB) diode laser with an emission wavelength near 1.4 μm was used for temperature measurement, which could cover two water vapor (H2O) absorption lines located at 7153.749 cm-1 and 7154.354 cm-1 simultaneously. The output wavelength of the diode laser was calibrated according to the two absorption peaks in the time domain. Using this strategy, the TDLAS system has the advantageous of immunization to laser wavelength shift, simple system structure, reduced cost, and increased system robustness. The line intensity of the two target absorption lines under room temperature was about one-thousandth of that under high temperature, which avoided the measuring error caused by H2O in the environment. The system was tested on a McKenna flat flame burner and a scramjet model engine, respectively. It was found that, compared to the results measured by CARS technique and theoretical calculation, this TDLAS system had less than 4% temperature error when the McKenna flat flame burner was used. When a scramjet model engine was adopted, the measured results showed that such TDLAS system had an excellent dynamic range and fast response. The TDLAS system reported here could be used in real engine in the future.
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Affiliation(s)
| | - Yufei Ma
- Correspondence: ; Tel.: +86-451-8641-3161
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3
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Bojęś P, Pokryszka P, Jaworski P, Yu F, Wu D, Krzempek K. Quartz-Enhanced Photothermal Spectroscopy-Based Methane Detection in an Anti-Resonant Hollow-Core Fiber. SENSORS (BASEL, SWITZERLAND) 2022; 22:5504. [PMID: 35898009 PMCID: PMC9330783 DOI: 10.3390/s22155504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 07/12/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
In this paper, the combination of using an anti-resonant hollow-core fiber (ARHCF), working as a gas absorption cell, and an inexpensive, commercially available watch quartz tuning fork (QTF), acting as a detector in the quartz-enhanced photothermal spectroscopy (QEPTS) sensor configuration is demonstrated. The proof-of-concept experiment involved the detection of methane (CH4) at 1651 nm (6057 cm-1). The advantage of the high QTF Q-factor combined with a specially designed low-noise amplifier and additional wavelength modulation spectroscopy with the second harmonic (2f-WMS) method of signal analysis, resulted in achieving a normalized noise-equivalent absorption (NNEA) at the level of 1.34 × 10-10 and 2.04 × 10-11 W cm-1 Hz-1/2 for 1 and 100 s of integration time, respectively. Results obtained in that relatively non-complex sensor setup show great potential for further development of cost-optimized and miniaturized gas detectors, taking advantage of the combination of ARHCF-based absorption cells and QTF-aided spectroscopic signal retrieval methods.
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Affiliation(s)
- Piotr Bojęś
- Faculty of Electronics, Photonics and Microsystem, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland; (P.P.); (P.J.); (K.K.)
| | - Piotr Pokryszka
- Faculty of Electronics, Photonics and Microsystem, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland; (P.P.); (P.J.); (K.K.)
| | - Piotr Jaworski
- Faculty of Electronics, Photonics and Microsystem, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland; (P.P.); (P.J.); (K.K.)
| | - Fei Yu
- Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China; (F.Y.); (D.W.)
- Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Dakun Wu
- Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China; (F.Y.); (D.W.)
- Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Karol Krzempek
- Faculty of Electronics, Photonics and Microsystem, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland; (P.P.); (P.J.); (K.K.)
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4
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Gattinger P, Zorin I, Ebner A, Rankl C, Brandstetter M. Mid-infrared DMD-based spectral-coding spectroscopy with a supercontinuum laser source. OPTICS EXPRESS 2022; 30:6440-6449. [PMID: 35209582 DOI: 10.1364/oe.452221] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 02/03/2022] [Indexed: 06/14/2023]
Abstract
We present a mid-infrared spectroscopic system based on a spectral-coding approach enabled by a modified digital micromirror device (DMD). A supercontinuum source offering a confined mid-infrared laser beam is employed to perform gas measurements with this system. The performance, flexibility, and programmability enabled by the DMD is experimentally demonstrated by gas-cell measurements (CO2, CH4, N2O, NO2 and CO). Full spectra are acquired in 14 ms at 10 nm spectral resolution and in 3.5 ms at 40 nm spectral resolution. Further, we employ the system for stand-off open-path spatially resolved CO2 measurements that fully exploit the laser emission properties - the bright and highly-collimated supercontinuum beam is scanned by a galvo mirror over a retroreflector array at a scalable remote distance. The measurement concept models a passing gas emitter under lab conditions; time and spatially resolved CO2 absorbance gas-plume images in the mid-infrared range are obtained.
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Zorin I, Gattinger P, Ebner A, Brandstetter M. Advances in mid-infrared spectroscopy enabled by supercontinuum laser sources. OPTICS EXPRESS 2022; 30:5222-5254. [PMID: 35209491 DOI: 10.1364/oe.447269] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/15/2021] [Indexed: 06/14/2023]
Abstract
Supercontinuum sources are all-fiber pulsed laser-driven systems that provide high power spectral densities within ultra-broadband spectral ranges. The tailored process of generating broadband, bright, and spectrally flat supercontinua-through a complex interplay of linear and non-linear processes-has been recently pushed further towards longer wavelengths and has evolved enough to enter the field of mid-infrared (mid-IR) spectroscopy. In this work, we review the current state and perspectives of this technology that offers laser-like emission properties and instantaneous broadband spectral coverage comparable to thermal emitters. We aim to go beyond a literature review. Thus, we first discuss the basic principles of supercontinuum sources and then provide an experimental part focusing on the quantification and analysis of intrinsic emission properties such as typical power spectral densities, brightness levels, spectral stability, and beam quality (to the best of the authors' knowledge, the M2 factor for a mid-IR supercontinuum source is characterized for the first time). On this basis, we identify key competitive advantages of these alternative emitters for mid-IR spectroscopy over state-of-the-art technologies such as thermal sources or quantum cascade lasers. The specific features of supercontinuum radiation open up prospects of improving well-established techniques in mid-IR spectroscopy and trigger developments of novel analytical methods and instrumentation. The review concludes with a structured summary of recent advances and applications in various routine mid-IR spectroscopy scenarios that have benefited from the use of supercontinuum sources.
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6
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Bozovic O, Jankovic B, Hamm P. Using azobenzene photocontrol to set proteins in motion. Nat Rev Chem 2021; 6:112-124. [PMID: 37117294 DOI: 10.1038/s41570-021-00338-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2021] [Indexed: 02/06/2023]
Abstract
Controlling the activity of proteins with azobenzene photoswitches is a potent tool for manipulating their biological function. With the help of light, it is possible to change binding affinities, control allostery or manipulate complex biological processes, for example. Additionally, owing to their intrinsically fast photoisomerization, azobenzene photoswitches can serve as triggers that initiate out-of-equilibrium processes. Such switching of the activity initiates a cascade of conformational events that can be accessed with time-resolved methods. In this Review, we show how the potency of azobenzene photoswitching can be combined with transient spectroscopic techniques to disclose the order of events and experimentally observe biomolecular interactions in real time. This strategy will further our understanding of how a protein can accommodate, adapt and readjust its structure to answer an incoming signal, revealing more of the dynamical character of proteins.
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7
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Buhrke D, Ruf J, Heckmeier P, Hamm P. A stop-flow sample delivery system for transient spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:123001. [PMID: 34972444 DOI: 10.1063/5.0068227] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 11/06/2021] [Indexed: 06/14/2023]
Abstract
A stop-flow sample delivery system for transient spectroscopy is presented, which is, in particular, suited for laser-based instruments (quantum-cascade lasers or amplified femtosecond lasers) with excitation pulse repetition rates in the range 10-100 Hz. Two pulsing micro-valves are mounted onto a flow cuvette designed for transient IR spectroscopy, which is integrated into a flow cycle driven by a peristaltic pump. The performance of the system is demonstrated with transient IR experiments of the trans-to-cis photoisomerization of a water-soluble azobenzene derivative. The sample stands still when the micro-valves are closed and is pushed out from the probe beam focus on a 1 ms timescale when opening the micro-valves. The setup is extremely sample efficient. It needs only small sample volumes, and at the same time, it enables excitation of a large fraction of molecules in solution.
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Affiliation(s)
- David Buhrke
- Department of Chemistry, University of Zurich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
| | - Jeannette Ruf
- Department of Chemistry, University of Zurich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
| | - Philipp Heckmeier
- Department of Chemistry, University of Zurich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
| | - Peter Hamm
- Department of Chemistry, University of Zurich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
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8
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Ettabib MA, Marti A, Liu Z, Bowden BM, Zervas MN, Bartlett PN, Wilkinson JS. Waveguide Enhanced Raman Spectroscopy for Biosensing: A Review. ACS Sens 2021; 6:2025-2045. [PMID: 34114813 DOI: 10.1021/acssensors.1c00366] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Waveguide enhanced Raman spectroscopy (WERS) utilizes simple, robust, high-index contrast dielectric waveguides to generate a strong evanescent field, through which laser light interacts with analytes residing on the surface of the waveguide. It offers a powerful tool for the direct identification and reproducible quantification of biochemical species and an alternative to surface enhanced Raman spectroscopy (SERS) without reliance on fragile noble metal nanostructures. The advent of low-cost laser diodes, compact spectrometers, and recent progress in material engineering, nanofabrication techniques, and software modeling tools have made realizing portable and cheap WERS Raman systems with high sensitivity a realistic possibility. This review highlights the latest progress in WERS technology and summarizes recent demonstrations and applications. Following an introduction to the fundamentals of WERS, the theoretical framework that underpins the WERS principles is presented. The main WERS design considerations are then discussed, and a review of the available approaches for the modification of waveguide surfaces for the attachment of different biorecognition elements is provided. The review concludes by discussing and contrasting the performance of recent WERS implementations, thereby providing a future roadmap of WERS technology where the key opportunities and challenges are highlighted.
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Affiliation(s)
- Mohamed A. Ettabib
- Zepler Institute for Photonics and Nanoelectronics, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Almudena Marti
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Zhen Liu
- Zepler Institute for Photonics and Nanoelectronics, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Bethany M. Bowden
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Michalis N. Zervas
- Zepler Institute for Photonics and Nanoelectronics, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Philip N. Bartlett
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - James S. Wilkinson
- Zepler Institute for Photonics and Nanoelectronics, University of Southampton, Southampton SO17 1BJ, United Kingdom
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9
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Affiliation(s)
- Peter Hamm
- Department of Chemistry, University of Zurich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
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10
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Winkowski M, Stacewicz T. Optical detection of formaldehyde in air in the 3.6 µm range. BIOMEDICAL OPTICS EXPRESS 2020; 11:7019-7031. [PMID: 33408977 PMCID: PMC7747927 DOI: 10.1364/boe.405384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/29/2020] [Accepted: 10/09/2020] [Indexed: 06/12/2023]
Abstract
The optical detector of formaldehyde designed for sensing cancer biomarkers in air exhaled from human lungs with possible application in free atmosphere is described. The measurements were performed at wavelengths ranging from 3595.77-3596.20 nm. It was stated that at the pressure of 0.01 atm this absorption band exhibits the best immunity to typical interferents that might occur at high concentration in human breath. Multipass absorption spectroscopy was also applied. The method of optical fringes quenching by wavelength modulation and signal averaging over the interferences period was presented. The application of such approaches enabled the detection limit of about single ppb to be achieved.
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11
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Liu N, Xu L, Zhou S, Zhang L, Li J. Simultaneous Detection of Multiple Atmospheric Components Using an NIR and MIR Laser Hybrid Gas Sensing System. ACS Sens 2020; 5:3607-3616. [PMID: 33137254 DOI: 10.1021/acssensors.0c01910] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A compact multi-gas sensor has been developed for simultaneous detection of atmospheric carbon monoxide (CO), nitrous oxide (N2O), and methane (CH4). Instead of the traditional time-division multiplexing detection technique, two lasers having center emission wavelengths of 1.653 μm (near-infrared (NIR) diode feedback (DFB) laser diode) and 4.56 μm (mid-infrared (MIR) quantum cascade laser) were simultaneously coupled to a multipass cell using a dichroic mirror, which significantly decreased the complexity of the measurement and increased the temporal resolution of the spectrometer. Wavelength modulation spectroscopy (WMS) with the second-harmonic detection technique (WMS-2f) was used to improve the detection sensitivity. A LabVIEW-based digital lock-in amplifier (DLIA) algorithm and system control unit was developed to make the system more compact and flexible. Allan deviation analysis indicates that detection limits of 6.36 ppb by volume for CO, 4.9 ppb by volume for N2O, and 23.6 ppb by volume for CH4 are obtained at 1 s averaging time, and the sensitivity can be improved to 0.44 ppb for CO, 0.41 ppb for N2O, and 2 ppb for CH4 at an optimal averaging time of 900 s. Two-day real-time measurement in ambient air was performed to demonstrate the long-term stability of the sensor system.
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Affiliation(s)
- Ningwu Liu
- Laser Spectroscopy and Sensing Laboratory, Anhui University, 230601 Hefei, China
| | - Linguang Xu
- Laser Spectroscopy and Sensing Laboratory, Anhui University, 230601 Hefei, China
| | - Sheng Zhou
- Laser Spectroscopy and Sensing Laboratory, Anhui University, 230601 Hefei, China
| | - Lei Zhang
- Laser Spectroscopy and Sensing Laboratory, Anhui University, 230601 Hefei, China
| | - Jingsong Li
- Laser Spectroscopy and Sensing Laboratory, Anhui University, 230601 Hefei, China
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12
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Potyrailo RA, Brewer J, Cheng B, Carpenter MA, Houlihan N, Kolmakov A. Bio-inspired gas sensing: boosting performance with sensor optimization guided by "machine learning". Faraday Discuss 2020; 223:161-182. [PMID: 32749434 PMCID: PMC7986473 DOI: 10.1039/d0fd00035c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The performance of existing gas sensors often degrades in field conditions because of the loss of measurement accuracy in the presence of interferences. Thus, new sensing approaches are required with improved sensor selectivity. We are developing a new generation of gas sensors, known as multivariable sensors, that have several independent responses for multi-gas detection with a single sensor. In this study, we analyze the capabilities of natural and fabricated photonic three-dimensional (3-D) nanostructures as sensors for the detection of different gaseous species, such as vapors and non-condensable gases. We employed bare Morpho butterfly wing scales to control their gas selectivity with different illumination angles. Next, we chemically functionalized Morpho butterfly wing scales with a fluorinated silane to boost the response of these nanostructures to the vapors of interest and to suppress the response to ambient humidity. Further, we followed our previously developed design rules for sensing nanostructures and fabricated bioinspired inorganic 3-D nanostructures to achieve functionality beyond natural Morpho scales. These fabricated nanostructures have embedded catalytically active gold nanoparticles to operate at high temperatures of ≈300 °C for the detection of gases for solid oxide fuel cell (SOFC) applications. Our performance advances in the detection of multiple gaseous species with specific nanostructure designs were achieved by coupling the spectral responses of these nanostructures with machine learning (a.k.a. multivariate analysis, chemometrics) tools. Our newly acquired knowledge from studies of these natural and fabricated inorganic nanostructures coupled with machine learning data analytics allowed us to advance our design rules for sensing nanostructures toward the required gas selectivity for numerous gas monitoring scenarios at room and high temperatures for industrial, environmental, and other applications.
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Affiliation(s)
| | - J Brewer
- GE Research, Niskayuna, NY, USA.
| | - B Cheng
- GE Research, Niskayuna, NY, USA.
| | | | - N Houlihan
- SUNY Polytechnic Institute, Albany, NY, USA
| | - A Kolmakov
- National Institute of Standards and Technology, Gaithersburg, MD, USA
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13
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Banik GD, Mizaikoff B. Exhaled breath analysis using cavity-enhanced optical techniques: a review. J Breath Res 2020; 14:043001. [PMID: 32969348 DOI: 10.1088/1752-7163/abaf07] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cavity-enhanced absorption spectroscopies (CEAS) have gained importance in a wide range of applications in molecular spectroscopy. The development of optical sensors based on the CEAS techniques coupled with the continuous wave or pulsed laser sources operating in the mid-infrared or near-infrared spectral regime uniquely offers molecularly selective and ultra-sensitive detection of trace species in complex matrices including exhaled human breath. In this review, we discussed recent applications of CEAS for analyzing trace constituents within the exhaled breath matrix facilitating the non-invasive assessment of human health status. Next to a brief discussion on the mechanisms of formation of trace components found in the exhaled breath matrix related to particular disease states, existing challenges in CEAS and future development towards non-invasive clinical diagnostics will be discussed.
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Affiliation(s)
- Gourab D Banik
- Institute of Analytical and Bioanalytical Chemistry, Ulm University Albert-Einstein-Allee 11, 89081 Ulm, Germany
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14
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Front-End Amplifiers for Tuning Forks in Quartz Enhanced PhotoAcoustic Spectroscopy. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10082947] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A study of the front-end electronics for quartz tuning forks (QTFs) employed as optoacoustic transducers in quartz-enhanced photoacoustic spectroscopy (QEPAS) sensing is reported. Voltage amplifier-based electronics is proposed as an alternative to the transimpedance amplifier commonly employed in QEPAS experiments. The possibility to use differential input/output configurations with respect to a single-ended configuration has also been investigated. Four different architectures have been realized and tested: a single-ended transimpedance amplifier, a differential output transimpedance amplifier, a differential input voltage amplifier and a fully differential voltage amplifier. All of these amplifiers were implemented in a QEPAS sensor operating in the mid-IR spectral range. Water vapor in ambient air has been selected as the target gas species for the amplifiers testing and validation. The signal-to-noise ratio (SNR) measured for the different configurations has been used to compare the performances of the proposed architectures. We demonstrated that the fully differential voltage amplifier allows for a nearly doubled SNR with respect to the typically used single-ended transimpedance amplifier.
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15
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Lin H, Huang Z, Kan R, Zheng H, Liu Y, Liu B, Dong L, Zhu W, Tang J, Yu J, Chen Z, Tittel FK. Application of Micro Quartz Tuning Fork in Trace Gas Sensing by Use of Quartz-Enhanced Photoacoustic Spectroscopy. SENSORS (BASEL, SWITZERLAND) 2019; 19:E5240. [PMID: 31795247 PMCID: PMC6928970 DOI: 10.3390/s19235240] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 11/26/2019] [Accepted: 11/26/2019] [Indexed: 12/05/2022]
Abstract
A novel quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor based on a micro quartz tuning fork (QTF) is reported. As a photoacoustic transducer, a novel micro QTF was 3.7 times smaller than the usually used standard QTF, resulting in a gas sampling volume of ~0.1 mm3. As a proof of concept, water vapor in the air was detected by using 1.39 μm distributed feedback (DFB) laser. A detailed analysis of the performance of a QEPAS sensor based on the micro QTF was performed by detecting atmosphere H2O. The laser focus position and the laser modulation depth were optimized to improve the QEPAS excitation efficiency. A pair of acoustic micro resonators (AmRs) was assembled with the micro QTF in an on-beam configuration to enhance the photoacoustic signal. The AmRs geometry was optimized to amplify the acoustic resonance. With a 1 s integration time, a normalized noise equivalent absorption coefficient (NNEA) of 1.97 × 10-8 W·cm-1·Hz-1/2 was achieved when detecting H2O at less than 1 atm.
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Affiliation(s)
- Haoyang Lin
- Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes, Department of Optoelectronic Engineering, Jinan University, Guangzhou 510632, China; (H.L.); (Z.H.); (Y.L.); (L.D.); (W.Z.); (J.T.); (J.Y.); (Z.C.)
| | - Zhao Huang
- Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes, Department of Optoelectronic Engineering, Jinan University, Guangzhou 510632, China; (H.L.); (Z.H.); (Y.L.); (L.D.); (W.Z.); (J.T.); (J.Y.); (Z.C.)
| | - Ruifeng Kan
- State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China;
| | - Huadan Zheng
- Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes, Department of Optoelectronic Engineering, Jinan University, Guangzhou 510632, China; (H.L.); (Z.H.); (Y.L.); (L.D.); (W.Z.); (J.T.); (J.Y.); (Z.C.)
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Jinan University, Guangzhou 510632, China
| | - Yihua Liu
- Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes, Department of Optoelectronic Engineering, Jinan University, Guangzhou 510632, China; (H.L.); (Z.H.); (Y.L.); (L.D.); (W.Z.); (J.T.); (J.Y.); (Z.C.)
| | - Bin Liu
- School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China;
| | - Linpeng Dong
- Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes, Department of Optoelectronic Engineering, Jinan University, Guangzhou 510632, China; (H.L.); (Z.H.); (Y.L.); (L.D.); (W.Z.); (J.T.); (J.Y.); (Z.C.)
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Jinan University, Guangzhou 510632, China
| | - Wenguo Zhu
- Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes, Department of Optoelectronic Engineering, Jinan University, Guangzhou 510632, China; (H.L.); (Z.H.); (Y.L.); (L.D.); (W.Z.); (J.T.); (J.Y.); (Z.C.)
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Jinan University, Guangzhou 510632, China
| | - Jieyuan Tang
- Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes, Department of Optoelectronic Engineering, Jinan University, Guangzhou 510632, China; (H.L.); (Z.H.); (Y.L.); (L.D.); (W.Z.); (J.T.); (J.Y.); (Z.C.)
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Jinan University, Guangzhou 510632, China
| | - Jianhui Yu
- Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes, Department of Optoelectronic Engineering, Jinan University, Guangzhou 510632, China; (H.L.); (Z.H.); (Y.L.); (L.D.); (W.Z.); (J.T.); (J.Y.); (Z.C.)
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Jinan University, Guangzhou 510632, China
| | - Zhe Chen
- Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes, Department of Optoelectronic Engineering, Jinan University, Guangzhou 510632, China; (H.L.); (Z.H.); (Y.L.); (L.D.); (W.Z.); (J.T.); (J.Y.); (Z.C.)
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Jinan University, Guangzhou 510632, China
| | - Frank K. Tittel
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA;
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16
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Lin C, Liao Y, Fang F. Trace Gas Detection System Based on All-Optical Quartz-Enhanced Photoacoustic Spectroscopy. APPLIED SPECTROSCOPY 2019; 73:1327-1333. [PMID: 31373509 DOI: 10.1177/0003702819866468] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
An all-optical quartz-enhanced photoacoustic spectroscopy system (QEPAS) with quadrature point stabilization for trace gas detection was reported. The extrinsic interferometry-based optical fiber Fabry-Perot sensor with quadrature point self-stabilization for detection of quartz prong vibration was used to replace the conventional one. The optimal coefficient of the modulation depth was ∼2.2 theoretically and experimentally, corresponding to the modulation depth of ∼0.1795 cm-1 at an acetylene (C2H2) absorption line of 6534.36 cm-1. Furthermore, the enhancement of QEPAS signal was obtained by using different microresonators. The minimum detectable limit of ∼580 parts per billion by volume (ppbv) was obtained. A normalized noise equivalent absorption coefficient for C2H2 of 2.95 × 10-7 cm-1·W·Hz-1/2 was obtained. The detection sensitivity was enhanced by a factor of ∼2.1 in comparison to the conventional QEPAS system. The linear correlation coefficient of the QEPAS signal response to the C2H2 concentration was 0.998 within the range from 10 parts per million by volume (ppmv) to 500 ppmv. Finally, the long-term stability of the QEPAS system was evaluated using Allan deviation analysis, and the ultimate detection limit of ∼130 ppbv was reached for an optimum averaging time of ∼108 s at atmospheric pressure and ambient temperature.
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Affiliation(s)
- Cheng Lin
- College of Physics and Electronic Information Engineering, Neijiang Normal University, Neijiang, China
| | - Yu Liao
- College of Physics and Electronic Information Engineering, Neijiang Normal University, Neijiang, China
| | - Fei Fang
- Research Center of Intelligent Manufacturing, Neijiang Normal University, Neijiang, China
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17
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Zhou S, Shen CY, Zhang L, Liu NW, He TB, Yu BL, Li JS. Dual-optimized adaptive Kalman filtering algorithm based on BP neural network and variance compensation for laser absorption spectroscopy. OPTICS EXPRESS 2019; 27:31874-31888. [PMID: 31684411 DOI: 10.1364/oe.27.031874] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 10/09/2019] [Indexed: 06/10/2023]
Abstract
A dual-optimized adaptive Kalman filtering (DO-AKF) algorithm based on back propagation (BP) neural network and variance compensation was developed for high-sensitivity trace gas detection in laser spectroscopy. The BP neural network was used to optimize the Kalman filter (KF) parameters. Variance compensation was introduced to track the state of the system and to eliminate the variations in the parameters of dynamic systems. The proposed DO-AKF algorithm showed the best performance compared with the traditional multi-signal average, extended KF, unscented KF, KF optimized by BP neural network (BP-KF) and KF optimized by variance compensation (VC-KF). The optimized DO-AKF algorithm was applied to a QCL-based gas sensor system for an exhaled CO analysis. The experimental results revealed a sensitivity enhancement factor of 23. The proposed algorithm can be widely used in the fields of environmental pollutant monitoring, industrial process control, and breath gas diagnosis.
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18
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Recent Developments in Modulation Spectroscopy for Methane Detection Based on Tunable Diode Laser. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9142816] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this review, methane absorption characteristics mainly in the near-infrared region and typical types of currently available semiconductor lasers are described. Wavelength modulation spectroscopy (WMS), frequency modulation spectroscopy (FMS), and two-tone frequency modulation spectroscopy (TTFMS), as major techniques in modulation spectroscopy, are presented in combination with the application of methane detection.
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19
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Kübel JM, Botha C, Bucka A, Höpfner J, Zimmermann H, Godejohann M, Wilhelm M. A New Quantum Cascade IR‐Laser Online Detector: Chemical‐Sensitive Size‐Exclusion Chromatography Measurement at Unprecedented Low Levels. Macromol Rapid Commun 2019; 40:e1900228. [DOI: 10.1002/marc.201900228] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/18/2019] [Indexed: 01/06/2023]
Affiliation(s)
- Jennifer M. Kübel
- Institute of Chemical Technology and Polymer ChemistryKarlsruhe Institute of Technology (KIT) Engesserstraße 18 76131 Karlsruhe Germany
| | - Carlo Botha
- Institute of Chemical Technology and Polymer ChemistryKarlsruhe Institute of Technology (KIT) Engesserstraße 18 76131 Karlsruhe Germany
| | - Aleksandra Bucka
- Institute of Chemical Technology and Polymer ChemistryKarlsruhe Institute of Technology (KIT) Engesserstraße 18 76131 Karlsruhe Germany
| | - Johannes Höpfner
- Institute of Chemical Technology and Polymer ChemistryKarlsruhe Institute of Technology (KIT) Engesserstraße 18 76131 Karlsruhe Germany
| | - Henrik Zimmermann
- neoplas control GmbH Walther‐Rathenau‐Straße 49a 17489 Greifswald Germany
| | | | - Manfred Wilhelm
- Institute of Chemical Technology and Polymer ChemistryKarlsruhe Institute of Technology (KIT) Engesserstraße 18 76131 Karlsruhe Germany
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20
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Winkowski M, Stacewicz T. Low noise, open-source QEPAS system with instrumentation amplifier. Sci Rep 2019; 9:1838. [PMID: 30755695 PMCID: PMC6372579 DOI: 10.1038/s41598-019-38509-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 12/28/2018] [Indexed: 11/19/2022] Open
Abstract
Quartz enhanced photoacoustic spectroscopy (QEPAS) is a rapidly developing, ultrasensitive method for trace gas sensing. Adequate electronic amplifier, well matched to the quartz characteristics is crucial for overall system performance. Here we present an open source circuit for QEPAS signal amplification. It consists of a buffer, instrumentation amplifier and digitally controlled gain stage. An experiment showed, that it offers signal to noise ratio of about 23 dB better than commonly used transimpedance amplifier. The use of this circuit provides opportunity to improve QEPAS sensitivity by about one order of magnitude.
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Affiliation(s)
- Mateusz Winkowski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland.
| | - Tadeusz Stacewicz
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland
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21
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Wallace MAG, Pleil JD. Evolution of clinical and environmental health applications of exhaled breath research: Review of methods and instrumentation for gas-phase, condensate, and aerosols. Anal Chim Acta 2018; 1024:18-38. [PMID: 29776545 PMCID: PMC6082128 DOI: 10.1016/j.aca.2018.01.069] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 01/29/2018] [Accepted: 01/31/2018] [Indexed: 12/20/2022]
Abstract
Human breath, along with urine and blood, has long been one of the three major biological media for assessing human health and environmental exposure. In fact, the detection of odor on human breath, as described by Hippocrates in 400 BC, is considered the first analytical health assessment tool. Although less common in comparison to contemporary bio-fluids analyses, breath has become an attractive diagnostic medium as sampling is non-invasive, unlimited in timing and volume, and does not require clinical personnel. Exhaled breath, exhaled breath condensate (EBC), and exhaled breath aerosol (EBA) are different types of breath matrices used to assess human health and disease state. Over the past 20 years, breath research has made many advances in assessing health state, overcoming many of its initial challenges related to sampling and analysis. The wide variety of sampling techniques and collection devices that have been developed for these media are discussed herein. The different types of sensors and mass spectrometry instruments currently available for breath analysis are evaluated as well as emerging breath research topics, such as cytokines, security and airport surveillance, cellular respiration, and canine olfaction.
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Affiliation(s)
- M Ariel Geer Wallace
- U.S. Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, 109 T.W. Alexander Drive, Research Triangle Park, NC, 27711, USA.
| | - Joachim D Pleil
- U.S. Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, 109 T.W. Alexander Drive, Research Triangle Park, NC, 27711, USA.
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22
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Zeng H, Li F, Yu X, Ou D, Chen L. Measurement of multispecies concentration and gas temperature in an ammonium-dinitramide-based thruster by tunable diode lasers. APPLIED OPTICS 2018; 57:1321-1330. [PMID: 29469829 DOI: 10.1364/ao.57.001321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 01/18/2018] [Indexed: 06/08/2023]
Abstract
In this paper, quantitative experiments were made to measure the concentration of key intermediate products (CO, N2O, and NO) and the gas temperature for combustion flow based on near-infrared and mid-infrared laser absorption spectroscopy. This paper used the developed diagnostic system to study two main ignition modes of a real 1-Newton thruster based on ammonium dinitramide (ADN): steady-state firing and pulse-mode firing over a feed pressure of 5-12 bar. The steady-state firing experiments distinguished the whole process into catalytic decomposition stage and combustion stage, experimentally demonstrating the combustion kinetics mechanism of an ADN monopropellant. Experiments for pulse-mode firing showed the measured multispecies concentration and temperature were consistent with pulse trains, verifying good performance for the thruster pulse-mode firing operation. The performance of the thruster was given based on the optical measurements, and characteristic velocity for the ADN-based thruster standard operation was higher than the corresponding 1-Newton hydrazine thruster.
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23
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A High Sensitivity Preamplifier for Quartz Tuning Forks in QEPAS (Quartz Enhanced PhotoAcoustic Spectroscopy) Applications. SENSORS 2017; 17:s17112528. [PMID: 29099765 PMCID: PMC5712872 DOI: 10.3390/s17112528] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 10/22/2017] [Accepted: 11/02/2017] [Indexed: 11/16/2022]
Abstract
All the preamplifiers dedicated for Quartz Enhanced PhotoAcoustic Spectroscopy (QEPAS) applications that have so far been reported in the literature have been based on operational amplifiers working in transimpedance configurations. Taking into consideration that QEPAS sensors are based on quartz tuning forks, and that quartz has a relatively high voltage constant and relatively low charge constant, it seems that a transimpedance amplifier is not an optimal solution. This paper describes the design of a quartz QEPAS sensor preamplifier, implemented with voltage amplifier configuration. Discussion of an electrical model of the circuit and preliminary measurements are presented. Both theoretical analysis and experiments show that use of the voltage configuration allows for a substantial increase of the output signal in comparison to the transimpedance circuit with the same tuning fork working in identical conditions. Assuming that the sensitivity of the QEPAS technique depends directly on the properties of the preamplifier, use of the voltage amplifier configuration should result in an increase of QEPAS sensitivity by one to two orders of magnitude.
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24
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Potyrailo RA. Toward high value sensing: monolayer-protected metal nanoparticles in multivariable gas and vapor sensors. Chem Soc Rev 2017; 46:5311-5346. [DOI: 10.1039/c7cs00007c] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This review provides analysis of advances in multivariable sensors based on monolayer-protected nanoparticles and several principles of signal transduction that result in building non-resonant and resonant electrical sensors as well as material- and structure-based photonic sensors.
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25
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Sun J, Deng H, Liu N, Wang H, Yu B, Li J. Mid-infrared gas absorption sensor based on a broadband external cavity quantum cascade laser. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:123101. [PMID: 28040920 DOI: 10.1063/1.4968041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We developed a laser absorption sensor based on a pulsed, broadband tunable external cavity quantum cascade laser (ECQCL) centered at 1285 cm-1. Unlike traditional infrared spectroscopy system, a quartz crystal tuning fork (QCTF) as a light detector was used for laser signal detection. Fast Fourier transform was applied to extract vibration intensity information of QCTF. The sensor system is successfully tested on nitrous oxide (N2O) spectroscopy measurements and compared with a standard infrared detector. The wide wavelength tunability of ECQCL will allow us to access the fundamental vibrational bands of many chemical agents, which are well-suited for trace explosive, chemical warfare agent, and toxic industrial chemical detection and spectroscopic analysis.
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Affiliation(s)
- Juan Sun
- Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education, Anhui University, 23061 Hefei, China
| | - Hao Deng
- Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education, Anhui University, 23061 Hefei, China
| | - Ningwu Liu
- Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education, Anhui University, 23061 Hefei, China
| | - Hongliang Wang
- National Deep Sea Center, State Oceanic Administration, 266237 Qingdao, China
| | - Benli Yu
- Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education, Anhui University, 23061 Hefei, China
| | - Jingsong Li
- Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education, Anhui University, 23061 Hefei, China
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26
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Galán-Freyle NJ, Pacheco-Londoño LC, Román-Ospino AD, Hernandez-Rivera SP. Applications of Quantum Cascade Laser Spectroscopy in the Analysis of Pharmaceutical Formulations. APPLIED SPECTROSCOPY 2016; 70:1511-1519. [PMID: 27558366 DOI: 10.1177/0003702816662609] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 03/07/2016] [Indexed: 06/06/2023]
Abstract
Quantum cascade laser spectroscopy was used to quantify active pharmaceutical ingredient content in a model formulation. The analyses were conducted in non-contact mode by mid-infrared diffuse reflectance. Measurements were carried out at a distance of 15 cm, covering the spectral range 1000-1600 cm(-1) Calibrations were generated by applying multivariate analysis using partial least squares models. Among the figures of merit of the proposed methodology are the high analytical sensitivity equivalent to 0.05% active pharmaceutical ingredient in the formulation, high repeatability (2.7%), high reproducibility (5.4%), and low limit of detection (1%). The relatively high power of the quantum-cascade-laser-based spectroscopic system resulted in the design of detection and quantification methodologies for pharmaceutical applications with high accuracy and precision that are comparable to those of methodologies based on near-infrared spectroscopy, attenuated total reflection mid-infrared Fourier transform infrared spectroscopy, and Raman spectroscopy.
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Affiliation(s)
- Nataly J Galán-Freyle
- ALERT DHS Center of Excellence for Explosives Research, Department of Chemistry, University of Puerto Rico, USA School of Basic and Biomedical Sciences, Universidad Simón Bolívar, Barranquilla, Colombia
| | - Leonardo C Pacheco-Londoño
- ALERT DHS Center of Excellence for Explosives Research, Department of Chemistry, University of Puerto Rico, USA Environmental Engineering Program, Vice-Rectory for Research, ECCI University, Bogotá, D.C., Colombia
| | | | - Samuel P Hernandez-Rivera
- ALERT DHS Center of Excellence for Explosives Research, Department of Chemistry, University of Puerto Rico, USA
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27
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Cole WT, Hlavacek NC, Lee AW, Kao TY, Hu Q, Reno JL, Saykally RJ. A Terahertz VRT spectrometer employing quantum cascade lasers. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.08.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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28
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Ritter E, Puskar L, Bartl FJ, Aziz EF, Hegemann P, Schade U. Time-resolved infrared spectroscopic techniques as applied to channelrhodopsin. Front Mol Biosci 2015. [PMID: 26217670 PMCID: PMC4493399 DOI: 10.3389/fmolb.2015.00038] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Among optogenetic tools, channelrhodopsins, the light gated ion channels of the plasma membrane from green algae, play the most important role. Properties like channel selectivity, timing parameters or color can be influenced by the exchange of selected amino acids. Although widely used, in the field of neurosciences for example, there is still little known about their photocycles and the mechanism of ion channel gating and conductance. One of the preferred methods for these studies is infrared spectroscopy since it allows observation of proteins and their function at a molecular level and in near-native environment. The absorption of a photon in channelrhodopsin leads to retinal isomerization within femtoseconds, the conductive states are reached in the microsecond time scale and the return into the fully dark-adapted state may take more than minutes. To be able to cover all these time regimes, a range of different spectroscopical approaches are necessary. This mini-review focuses on time-resolved applications of the infrared technique to study channelrhodopsins and other light triggered proteins. We will discuss the approaches with respect to their suitability to the investigation of channelrhodopsin and related proteins.
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Affiliation(s)
- Eglof Ritter
- Experimentelle Biophysik, Institut für Biologie, Humboldt-Universität zu Berlin Berlin, Germany
| | - Ljiljana Puskar
- Methods for Material Development, Helmholtz-Zentrum für Materialien und Energie GmbH Berlin, Germany
| | - Franz J Bartl
- Institut für medizinische Physik und Biophysik, Charité - Universitätsmedizin Berlin Berlin, Germany
| | - Emad F Aziz
- Methods for Material Development, Helmholtz-Zentrum für Materialien und Energie GmbH Berlin, Germany ; Fachbereich Physik, Freie Universität Berlin Berlin, Germany
| | - Peter Hegemann
- Experimentelle Biophysik, Institut für Biologie, Humboldt-Universität zu Berlin Berlin, Germany
| | - Ulrich Schade
- Methods for Material Development, Helmholtz-Zentrum für Materialien und Energie GmbH Berlin, Germany
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29
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Li J, Yu B, Fischer H. Wavelet transform based on the optimal wavelet pairs for tunable diode laser absorption spectroscopy signal processing. APPLIED SPECTROSCOPY 2015; 69:496-506. [PMID: 25741689 DOI: 10.1366/14-07629] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This paper presents a novel methodology-based discrete wavelet transform (DWT) and the choice of the optimal wavelet pairs to adaptively process tunable diode laser absorption spectroscopy (TDLAS) spectra for quantitative analysis, such as molecular spectroscopy and trace gas detection. The proposed methodology aims to construct an optimal calibration model for a TDLAS spectrum, regardless of its background structural characteristics, thus facilitating the application of TDLAS as a powerful tool for analytical chemistry. The performance of the proposed method is verified using analysis of both synthetic and observed signals, characterized with different noise levels and baseline drift. In terms of fitting precision and signal-to-noise ratio, both have been improved significantly using the proposed method.
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Affiliation(s)
- Jingsong Li
- Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education, Anhui University, No. 111 Jiulong Road, Hefei 230039, China
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