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Zeng Y, Hutzler NR. Nonresonant cavity for multipass laser intensity buildup. APPLIED OPTICS 2023; 62:3574-3580. [PMID: 37706972 DOI: 10.1364/ao.487531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 04/09/2023] [Indexed: 09/15/2023]
Abstract
A nonresonant cavity to build up laser intensity is modeled, developed, and tested. It can be used for overlapping multiple lasers of different wavelengths, increasing their intensities by more than an order of magnitude while maintaining good uniformity. It is simple to set up, has flexible optical characteristics, and is robust against perturbations. The intensity buildup requires no resonances, and the wavelength dependence of the performance is limited only by the mirror coatings. The cavity can be used, for example, in applications requiring a spatially constrained intensity buildup, such as in atomic and molecular traps.
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2
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Kong R, Ma N, Liu P, Zhou X. Dual trace gas detection using a compact two-channel multipass cell with dense and line spot patterns. Heliyon 2023; 9:e13677. [PMID: 36879754 PMCID: PMC9984412 DOI: 10.1016/j.heliyon.2023.e13677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/13/2023] Open
Abstract
A highly sensitive dual-gas sensor based on a two-channel multipass cell (MPC) was designed and developed for simultaneous detection of atmospheric methane (CH4) and carbon dioxide (CO2) by using two distributed feedback lasers emitting at 1653 nm and 2004 nm. The nondominated sorting genetic algorithm was applied to intelligently optimize the MPC configuration and accelerate the dual-gas sensor design process. A compact and novel two-channel MPC was used to achieve two optical path lengths of 27.6 m and 2.1 m in a small volume of 233 cm3. Simultaneous measurements of CH4 and CO2 in the atmosphere were performed to demonstrate the stability and robustness of the gas sensor. According to the Allan deviation analysis, the optimal detection precision for CH4 and CO2 was 4.4 ppb at an integration time of 76 s and 437.8 ppb at an integration time of 271 s, respectively. The newly developed dual-gas sensor exhibits superior characteristics of high sensitivity and stability, cost-effectiveness and simple structure, which make it well-suited for multiple trace gas sensing in various applications, including environmental monitoring, safety inspections and clinical diagnosis.
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Affiliation(s)
- Rong Kong
- Center for Advanced Quantum Studies, Applied Optics Beijing Area Major Laboratory, Department of Physics, Beijing Normal University, Beijing, 100875, China
| | - Ningyi Ma
- Center for Advanced Quantum Studies, Applied Optics Beijing Area Major Laboratory, Department of Physics, Beijing Normal University, Beijing, 100875, China
| | - Peng Liu
- Center for Advanced Quantum Studies, Applied Optics Beijing Area Major Laboratory, Department of Physics, Beijing Normal University, Beijing, 100875, China
| | - Xin Zhou
- Center for Advanced Quantum Studies, Applied Optics Beijing Area Major Laboratory, Department of Physics, Beijing Normal University, Beijing, 100875, China
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3
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Ou X, Liu P, Zhou X. Generalized design of simple, stable and compact nested multipass cells with a reentrant symmetric concentric circle pattern. OPTICS EXPRESS 2023; 31:4152-4163. [PMID: 36785390 DOI: 10.1364/oe.479762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
We present a particular solution of the Herriott design by replacing each spherical mirror with two coaxial nested spherical mirrors with different curvatures. The analytical solution of the nested MPC parameters is derived based on the principle of the Herriott cell and the symmetry of the pattern, which enables the rapid design of nested MPCs with different optical path lengths (OPLs). The nested MPC performance is explored by parameter analysis, the ray tracing method and the transfer matrix method. We further designed and manufactured a miniaturized and long-OPL MPC, which exhibits robustness, high mirror utilization and a good q-parameter of the output beam. The miniaturized nested MPC can achieve a 10 m effective OPL at a volume of 28.4 mL, and the long-OPL MPC can obtain a 100 m effective OPL at a volume of 1.3 L.
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Mikkonen T, Hieta T, Genty G, Toivonen J. Sensitive multi-species photoacoustic gas detection based on mid-infrared supercontinuum source and miniature multipass cell. Phys Chem Chem Phys 2022; 24:19481-19487. [DOI: 10.1039/d2cp01731h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report multipass broadband photoacoustic spectroscopy of trace gases in the mid-infrared. The measurement principle of the sensor relies on supercontinuum-based Fourier transform photoacoustic spectroscopy (FT-PAS), in which a scanning...
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Smith NMJ, Couper J, Richmond G, Sandhu D, Hancock G, Robbins PA, Ritchie GAD. Development of in-airway laser absorption spectroscopy for respiratory based measurements of cardiac output. Sci Rep 2021; 11:5252. [PMID: 33664377 PMCID: PMC7970843 DOI: 10.1038/s41598-021-84649-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 02/18/2021] [Indexed: 11/09/2022] Open
Abstract
Respiratory approaches to determining cardiac output in humans are securely rooted in mass balance and therefore potentially highly accurate. To address existing limitations in the gas analysis, we developed an in-airway analyser based on laser absorption spectroscopy to provide analyses every 10 ms. The technique for estimating cardiac output requires both a relatively soluble and insoluble tracer gas, and we employed acetylene and methane for these, respectively. A multipass cell was used to provide sufficient measurement sensitivity to enable analysis directly within the main gas stream, thus avoiding errors introduced by sidestream gas analysis. To assess performance, measurements of cardiac output were made during both rest and exercise on five successive days in each of six volunteers. The measurements were extremely repeatable (coefficient of variation ~ 7%). This new measurement technology provides a stable foundation against which the algorithm to calculate cardiac output can be further developed.
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Affiliation(s)
- Nicholas M J Smith
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK
| | - John Couper
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK
| | - Graham Richmond
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK
| | - Dominic Sandhu
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK
| | - Gus Hancock
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK
| | - Peter A Robbins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Grant A D Ritchie
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK.
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Webster CR, Flesch GJ, Briggs RM, Fradet M, Christensen LE. Herriott cell spot imaging increases the performance of tunable laser spectrometers. APPLIED OPTICS 2021; 60:1958-1965. [PMID: 33690287 DOI: 10.1364/ao.417074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/07/2021] [Indexed: 06/12/2023]
Abstract
With the availability of high-power (milliwatts) single-mode tunable laser sources that operate at room temperature across the infrared (IR) region, tunable laser spectrometers have seen an explosion of growth in applications that include commercial, Earth and planetary science, and medical and industrial sensing. While the laser sources themselves have shown steady improvement, the detection architecture of using a single-element detector at one end of a multipass cell has remained unchanged over the last few decades. We present here an innovative new approach using a detector array coupled to an IR-transmissive mirror to image all or part of the multipass spot pattern of the far mirror and record spectra for each pixel. This novel approach offers improved sensitivity, increased dynamic range, laser power normalization, contaminant subtraction, resilience to misalignment, and reduces the instrument power requirement by avoiding the need for "fringe-wash" heaters. With many tens of pixels representing each spot during the laser spectral scan, intensity and optical fringe amplitude and phase information are recorded. This allows selection and manipulation (e.g., co-addition, subtraction) of the pixel output spectra to minimize optical interference fringes thereby increasing sensitivity. We demonstrate a factor of ∼20 sensitivity improvement over traditional single-element detection. Dynamic range increase of a factor of ∼100 is also demonstrated through spot selection representing different pathlengths. Additionally, subtracting the spectrum of the first spot from that of the higher pass normalizes the laser power and removes the contribution of contaminant gas and fringes in the fore-optics region. These initial results show that this imaging method is particularly advantageous for multi-channel laser spectrometers, and, once the image field is analyzed, pixel selection can be used to minimize data rate and volume collection requirements. This technique could be beneficial to enhanced-cavity detection schemes.
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Takida Y, Nawata K, Minamide H. Security screening system based on terahertz-wave spectroscopic gas detection. OPTICS EXPRESS 2021; 29:2529-2537. [PMID: 33726446 DOI: 10.1364/oe.413201] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 12/27/2020] [Indexed: 06/12/2023]
Abstract
Tunable terahertz (THz)-wave absorption spectroscopy is a promising technique to detect trace gases suspended in ambient air owing to their strong absorption fingerprints in the THz-wave spectral region. Here, we present a THz-wave spectroscopic gas detection platform based on a frequency-tunable injection-seeded THz-wave parametric generator and compact multipass gas absorption cells. Using a 1.8-m-path-length multipass cell, we detected gas-phase methanol (CH3OH) down to a trace concentration of 0.2 ppm at the 1.48-THz transparent atmospheric window. We also developed a transportable walk-through screening prototype using a 6-m-path-length multipass cell to identify suspicious subjects. Our results demonstrate the potential of the proposed system for security screening applications.
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Nadeem F, Postma BR, Postma G, Cristescu SM, Mandon J, Harren FJM. Comprehensive three-dimensional ray tracing model for three-mirror cavity-enhanced spectroscopy. APPLIED OPTICS 2018; 57:154-163. [PMID: 29328166 DOI: 10.1364/ao.57.000154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 12/04/2017] [Indexed: 06/07/2023]
Abstract
A 3D ray tracing model is used to simulate optical reinjection in a nonresonant optical cavity, for off-axis integrated cavity output spectroscopy. The optical cavities are optimized for maximum intensity enhancement factors via a grid search and a genetic algorithm. Intensity enhancement factors up to 1400 are found for short cavities (3 cm) and up to 101 for long cavities (50 cm). The model predicts that short absorption cells can be used, having a long effective path length and a high throughput power. This opens new opportunities in the field of ultrasensitive absorption spectroscopy and allows the design of compact optical gas sensors.
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Dahlen D, Wilcox R, Leemans W. Modeling Herriott cells using the linear canonical transform. APPLIED OPTICS 2017; 56:267-272. [PMID: 28085861 DOI: 10.1364/ao.56.000267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We demonstrate a new way to analyze stable, multipass optical cavities (Herriott cells), using the linear canonical transform formalism, showing that re-entrant designs reproduce an arbitrary input field at the output, resulting in useful symmetries. We use this analysis to predict the stability of cavities used in interferometric delay lines for temporal pulse addition.
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Kühnreich B, Höh M, Wagner S, Ebert V. Direct single-mode fibre-coupled miniature White cell for laser absorption spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:023111. [PMID: 26931838 DOI: 10.1063/1.4941748] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present the design, setup, and characterization of a new lens-free fibre-coupled miniature White cell for extractive gas analysis using direct tunable diode laser absorption spectroscopy (dTDLAS). The construction of this cell is based on a modified White cell design and allows for an easy variation of the absorption length in the range from 29 cm to 146 cm. The design avoids parasitic absorption paths outside the cell by using direct, lensless fibre coupling and allows small physical cell dimensions and cell volumes. To characterize the cell performance, different H2O and CH4 concentration levels were measured using dTDLAS. Detection limits of 2.5 ppm ⋅ m for CH4 (at 1.65 μm) and 1.3 ppm ⋅ m for H2O (at 1.37 μm) were achieved. In addition, the gas exchange time and its flow-rate dependence were determined for both species and found to be less than 15 s for CH4 and up to a factor of thirteen longer for H2O.
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Affiliation(s)
- Benjamin Kühnreich
- High Temperature Process Diagnostics, Technische Universität Darmstadt, Darmstadt, Germany
| | - Matthias Höh
- Reactive Flows and Diagnostics, Technische Universität Darmstadt, Darmstadt, Germany
| | - Steven Wagner
- High Temperature Process Diagnostics, Technische Universität Darmstadt, Darmstadt, Germany
| | - Volker Ebert
- Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
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Boyson TK, Dagdigian PJ, Pavey KD, FitzGerald NJ, Spence TG, Moore DS, Harb CC. Real-time multiplexed digital cavity-enhanced spectroscopy. OPTICS LETTERS 2015; 40:4560-4562. [PMID: 26421581 DOI: 10.1364/ol.40.004560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Cavity-enhanced spectroscopy is a sensitive optical absorption technique but one where the practical applications have been limited to studying small wavelength ranges. This Letter shows that wideband operation can be achieved by combining techniques usually reserved for the communications community with that of cavity-enhanced spectroscopy, producing a multiplexed real-time cavity-enhanced spectrometer. We use multiple collinear laser sources operating asynchronously and simultaneously while being detected on a single photodetector. This is synonymous with radio frequency (RF) cellular systems in which signals are detected on a single antenna but decoded uniquely. Here, we demonstrate results with spectra of methyl salicylate and show parts-per-billion per root hertz sensitivity measured in real-time.
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Boyson TK, Rittman DR, Spence TG, Calzada ME, Kallapur AG, Petersen IR, Paul Kirkbride K, Moore DS, Harb CC. Pulsed quantum cascade laser based hypertemporal real-time headspace measurements. OPTICS EXPRESS 2014; 22:10519-10534. [PMID: 24921754 DOI: 10.1364/oe.22.010519] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Optical cavity enhancement is a highly desirable process to make sensitive direct-absorption spectroscopic measurements of unknown substances, such as explosives, illicit material, or other species of interest. This paper reports advancements in the development of real-time cavity ringdown spectroscopy over a wide-bandwidth, with the aim to make headspace measurements of molecules at trace levels. We report results of two pulsed quantum cascade systems operating between (1200 to 1320)cm(-1) and (1316 to 1613)cm(-1) that measure the headspace of nitromethane, acetonitrile, acetone, and nitroglycerin, where the spectra are obtained in less than four seconds and contain at least 150,000 spectral wavelength datapoints.
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Michel M, Rocha L, Hamel M, Normand S, Angélique JC. Distributed feedback lasing of commercial liquid scintillators. OPTICS LETTERS 2013; 38:5307-5310. [PMID: 24322244 DOI: 10.1364/ol.38.005307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
It is shown that lasing can be achieved in commercial organic liquid scintillators. Using a dynamic grating induced by an interference pattern in the scintillator volume, distributed feedback lasing is shown to occur in four out of five commercial liquid scintillators that have been investigated. Although these scintillators are not designed for lasing application, their purpose being to measure radioactivity, induction of a laser effect, furthermore with a tuning range of approximately 30 nm, has been attained.
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Briggs RM, Frez C, Bagheri M, Borgentun CE, Gupta JA, Witinski MF, Anderson JG, Forouhar S. Single-mode 2.65 µm InGaAsSb/AlInGaAsSb laterally coupled distributed-feedback diode lasers for atmospheric gas detection. OPTICS EXPRESS 2013; 21:1317-1323. [PMID: 23389025 DOI: 10.1364/oe.21.001317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We demonstrate index-coupled distributed-feedback diode lasers at 2.65 µm that are capable of tuning across strong absorption lines of HDO and other isotopologues of H2O. The lasers employ InGaAsSb/AlInGaAsSb multi-quantum-well structures grown by molecular beam epitaxy on GaSb, and single-mode emission is generated using laterally coupled second-order Bragg gratings etched alongside narrow ridge waveguides. We verify near-critical coupling of the gratings by analyzing the modal characteristics of lasers of different length. With an emission facet anti-reflection coating, 2-mm-long lasers exhibit a typical current threshold of 150 mA at 20 °C and are capable of emitting more than 25 mW in a single longitudinal mode, which is significantly higher than the output power reported for loss-coupled distributed-feedback lasers operating at similar wavelengths.
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Affiliation(s)
- Ryan M Briggs
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
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Uddi M, Das AK, Sung CJ. Temperature measurements in a rapid compression machine using mid-infrared H2O absorption spectroscopy near 7.6 μm. APPLIED OPTICS 2012; 51:5464-5476. [PMID: 22859037 DOI: 10.1364/ao.51.005464] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 06/22/2012] [Indexed: 06/01/2023]
Abstract
A method for measuring the temporal temperature and number density in a rapid compression machine (RCM) using quantum cascade laser absorption spectroscopy near 7.6 μm is developed and presented in this paper. The ratios of H(2)O absorption peaks at 1316.55 cm(-1) and 1316.97 cm(-1) are used for these measurements. In order to isolate the effects of chemical reactions, an inert mixture of argon with 2.87% water vapor is used for the present investigation. The end of compression pressures and temperatures in the RCM measurements are P(C)=10, 15, and 20 bar in the range of T(C)=1000 to 1200 K. The measured temperature history is compared with that calculated based on the adiabatic core assumption and is found to be within ±5 K. The measured temporal number density of H(2)O to an accuracy of 1%, using the absolute absorption of the two rovibrational lines, show that the mixture is highly uniform in temperature. A six-pass, 5.08 cm Herriott cell is used to calibrate the line strengths in air and broadening in an Ar bath gas.
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Affiliation(s)
- Mruthunjaya Uddi
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA.
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Wunderle K, Wagner S, Pasti I, Pieruschka R, Rascher U, Schurr U, Ebert V. Distributed feedback diode laser spectrometer at 2.7 microm for sensitive, spatially resolved H2O vapor detection. APPLIED OPTICS 2009; 48:B172-B182. [PMID: 19183576 DOI: 10.1364/ao.48.00b172] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A new, compact, spatially scanning, open-path 2.7 microm tunable diode laser absorption spectrometer with short absorption path lengths below 10 cm was developed to analyze the spatiotemporal dynamics of one-dimensional (1D) spatial water vapor gradients. This spectrometer, which is based on a room-temperature distributed feedback diode laser, is capable of measuring absolute, calibration-free, line-of-sight averaged, but laterally resolved 1D H(2)O concentration profiles with a minimum fractional optical resolution of 2.1x10(-3) optical density (OD) (2.5x10(-4) OD after a background subtraction procedure), which permits a signal-to-noise-ratio of 407 (3400) at 10,000 parts in 10(6) (ppm)H(2)O, or normalized sensitivities of 2.6 ppm x m (0.32 ppm m) at 0.5 Hz duty cycle. The spectrometer's lateral spatial resolution (governed by the 500 microm sampling beam diameter) was validated by analyzing a well-defined laminar jet of nitrogen gas in humidified air. This scanning setup was then used to (a) quantitatively investigate for what we believe to be the first time the H(2)O boundary layer from 0.7 to 11 mm beneath the stomatous side of a single, undetached plant leaf, and (b) to study the temporal boundary layer dynamics and its dependence on stepwise light stimulation of the photosynthetic system. In addition the 2.7 microm diode laser was carefully characterized in terms of spectral purity, beam profile, as well as quasi-static and dynamic wavelength tuning coefficients.
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Affiliation(s)
- Karl Wunderle
- Physical-Chemistry Institute PCI, INF 253, 69120 Heidelberg, Germany
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