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Articles de revues sur le sujet « Noice spectroscopy »

Auteur : Grafiati

Publié le 10 mars 2023

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1

Chao Shen, Chao Shen, Yujun Zhang Yujun Zhang et Jiazheng Ni Jiazheng Ni. « Real-time adaptive noise cancelling for signal-to-noise enhancement in direct absorption spectroscopy ». Chinese Optics Letters 11, n^o 7 (2013) : 073001–73004. http://dx.doi.org/10.3788/col201311.073001.

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Velichko, E. N., O. I. Kotov, E. K. Nepomnyashchaya, A. N. Petrov et A. V. Sokolov. « On Basic Requirements to Main Elements of Laser Correlation Spectrometer ». Journal of the Russian Universities. Radioelectronics 23, n^o 1 (28 février 2020) : 83–95. http://dx.doi.org/10.32603/1993-8985-2020-23-1-83-95.

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Introduction. Laser correlation spectroscopy is a promising method that allows one to analyze sizes of nanoparticles and to evaluate their shape and dynamics of aggregation in liquids. A limited usage of laser correlation spectroscopy is currently caused by insufficient accuracy of existing instruments and data processing algorithms. The paper described the development of laser correlation spectroscopic hardware complex designed for nanoparticles size determination in liquids. The basic requirements for the elements of the device and the approaches used to calculate the signal-to-noise ratio were discussed. The achieved parameters of the laser correlation spectrometer were presented.Aim. To develop the hardware for nanoparticles size determination in liquids and to optimize the parameters of hardware elements to increase signal-to-noise ratio.Materials and methods. Theory of dynamic light scattering to describe scattering of laser radiation in liquids was applied. Fundamental requirements for the elements of the laser correlation spectrometer were described.Results. An original scheme of the laser correlation spectrometer was developed, the basic requirements for the general scheme elements were described. Equations for calculating signal-to-noise ratio were given.Conclusion. The analysis of the main parameters of the elements of the laser correlation spectroscopic scheme were carried out. It helps one to evaluate the expected signal-to-noise ratio in laser correlation spectrometers.

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Hu, Mengyuan, Andrea Ventura, Juliano Grigoleto Hayashi, Francesco Poletti et Wei Ren. « Mid-Infrared Frequency Modulation Spectroscopy of NO Detection in a Hollow-Core Antiresonant Fiber ». Photonics 9, n^o 12 (3 décembre 2022) : 935. http://dx.doi.org/10.3390/photonics9120935.

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Mid-infrared frequency modulation spectroscopy (FMS) in a tellurite hollow-core antiresonant fiber (HC-ARF) is investigated for gas detection. The spectroscopic system is demonstrated for nitric oxide (NO) detection by exploiting its strong absorption line at 1900.08 cm−1 with a quantum cascade laser (QCL). By modulating the injection current of the QCL at 250 MHz and measuring NO in a 35 cm long HC-ARF, we achieve a noise equivalent concentration of 67 ppb at an averaging time of 0.1 s. Compared to direct absorption spectroscopy with a low-pass filter for etalon noise reduction, the FMS technique shows an improvement factor of 22. The detection limit of FMS can be further improved to 6 ppb at a longer averaging time of 100 s, corresponding to a noise equivalent absorption coefficient of 1.0 × 10−7 cm−1.

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Weng, Kanxing, Bin Wu, Feichen Wang, Xiaohui Zhang, Yin Zhou, Bing Cheng et Qiang Lin. « The Influence of Temperature on Frequency Modulation Spectroscopy in Atom Gravimeter ». Sensors 22, n^o 24 (16 décembre 2022) : 9935. http://dx.doi.org/10.3390/s22249935.

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Atom gravimeters use locked lasers to manipulate atoms to achieve high-precision gravity measurements. Frequency modulation spectroscopy (FMS) is an accurate method of optical heterodyne spectroscopy, capable of the sensitive and rapid frequency locking of the laser. Because of the effective absorption coefficient, Doppler broadening and susceptibility depend on temperature, and the signal-to-noise ratio (SNR) of the spectroscopy could be affected by temperature. We present a detailed study of the influence of the temperature on FMS in atom gravimeters, and the experimental results show that the SNR of the spectroscopy is dependent on temperature. In this paper, the frequency of the reference laser is locked by tracking the set point of the fringe slope of FMS. The influence of the frequency-locking noise of the reference laser on the sensitivity of the atom gravimeter is investigated by changing the temperature of the Rb cell without extra operations. The method presented here could be useful for improving the sensitivity of quantum sensors that require laser spectroscopic techniques.

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Aleksandrov, E. B., et V. S. Zapasskii. « Spin Noise Spectroscopy ». Journal of Physics : Conference Series 324 (21 octobre 2011) : 012002. http://dx.doi.org/10.1088/1742-6596/324/1/012002.

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Paldus, Barbara A., et Alexander A. Kachanov. « An historical overview of cavity-enhanced methods ». Canadian Journal of Physics 83, n^o 10 (1 octobre 2005) : 975–99. http://dx.doi.org/10.1139/p05-054.

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An historical overview of laser-based, spectroscopic methods that employ high-finesse optical resonators is presented. The overview begins with the early work in atomic absorption (1962) and optical cavities (1974) that led to the first mirror reflectivity measurements in 1980. This paper concludes with very recent extensions of cavity-enhanced methods for the study of condensed-phase media and biological systems. Methods described here include cavity ring-down spectroscopy, integrated cavity output spectroscopy, and noise-immune cavity-enhanced optical heterodyne molecular spectroscopy. Given the explosive growth of the field over the past decade, this review does not attempt to present a comprehensive bibliography of all work published in cavity-enhanced spectroscopy, but rather strives to illustrate the rich history, creative diversity, and broad applications potential of these methods. PACS No.: 39.30.+w

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Ishibe, Kiyoshiro, Satoru Nakada, Yutaka Mera et Koji Maeda. « Nanoprobe Fourier-Transform Photoabsorption Spectroscopy Using a Supercontinuum Light Source ». Microscopy and Microanalysis 18, n^o 3 (3 mai 2012) : 591–95. http://dx.doi.org/10.1017/s1431927612000219.

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AbstractA scheme of photoabsorption spectroscopy based on scanning tunneling microscopy (STM) has been developed by using a supercontinuum light as the wideband light source of a Fourier transform interferometer for spectroscopic measurements. The performance was demonstrated for a sample of GaAs. The proof-of-concept test showed that the use of the supercontinuum light instead of halogen lamps greatly enhances the signal-to-noise ratio due to the high brilliance of the supercontinuum light emitted from a small core of the photonic crystal fiber that enables tight focusing of the spectroscopy light onto the sample beneath the STM tip.

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Peng, Zhimin, Yanjun Du et Yanjun Ding. « Highly Sensitive, Calibration-Free WM-DAS Method for Recovering Absorbance—Part I : Theoretical Analysis ». Sensors 20, n^o 3 (26 janvier 2020) : 681. http://dx.doi.org/10.3390/s20030681.

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The absorbance is of great importance in the tunable diode laser absorption spectroscopy (TDLAS) as it contains information of both gas properties and spectroscopic parameters. A novel, calibration-free wavelength modulation-direct absorption spectroscopy (WM-DAS) is proposed and experimentally verified in this two-part paper. This method combines the capability of absorbance measurement from DAS and the advantages of enhanced noise rejection and high sensitivity from WMS. In this Part I, we focus on the full theoretical basis and procedures of this method from the following three aspects: the high-accuracy characterizations of laser frequency and intensity, noise rejection ability by extracting the characteristic spectra through the fast Fourier transform (FFT) of the light intensity, and the simultaneous fitting strategy for both baseline and absorbance. The preliminary validation experiment of CO transition at 4300.6999 cm−1 in a static gas cell shows the high accuracy of the proposed method.

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Starosielec, Sebastian, et Daniel Hägele. « Ultrafast spin noise spectroscopy ». Applied Physics Letters 93, n^o 5 (4 août 2008) : 051116. http://dx.doi.org/10.1063/1.2969041.

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Ferrie, Chris, Chris Granade, Gerardo Paz-Silva et Howard M. Wiseman. « Bayesian quantum noise spectroscopy ». New Journal of Physics 20, n^o 12 (5 décembre 2018) : 123005. http://dx.doi.org/10.1088/1367-2630/aaf207.

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Jones, B. K. « Low-frequency noise spectroscopy ». IEEE Transactions on Electron Devices 41, n^o 11 (1994) : 2188–97. http://dx.doi.org/10.1109/16.333840.

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Bojęś, Piotr, Piotr Pokryszka, Piotr Jaworski, Fei Yu, Dakun Wu et Karol Krzempek. « Quartz-Enhanced Photothermal Spectroscopy-Based Methane Detection in an Anti-Resonant Hollow-Core Fiber ». Sensors 22, n^o 15 (23 juillet 2022) : 5504. http://dx.doi.org/10.3390/s22155504.

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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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Sato, Hidetoshi, Satoshi Wada et Hideo Tashiro. « Fluorescence Backgroundless Ti : Sapphire Laser Using Acousto-Optical Tunable Filter for Raman Spectroscopic Measurements ». Applied Spectroscopy 56, n^o 10 (octobre 2002) : 1303–7. http://dx.doi.org/10.1366/000370202760355019.

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The background noise inherent to tunable lasers, which emit broad band spontaneous fluorescence from the laser-active medium, is detrimental for sensitive Raman measurement. Using the diffraction effect in an acousto-optic device, we have developed a fluorescence backgroundless Ti: sapphire laser suited for near-infrared Raman spectroscopy. A Raman excitation profile consisting of series of Raman spectra of deoxygenated hemoglobin aqueous solutions was measured by changing excitation wavelengths, revealing the high potential of this laser as a spectroscopic light source.

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Yano, Kaori, et Toshiaki Hattori. « Improving a Terahertz Time-Domain Spectroscopy Apparatus Using Neodymium Magnets ». International Letters of Chemistry, Physics and Astronomy 62 (novembre 2015) : 10–14. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.62.10.

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The signal-to-noise ratio obtained from terahertz time-domain spectroscopy is significantly affected by the low available power of terahertz waves. We constructed a terahertz-wave source with emission power enhanced by a magnetic field. The emitter is composed of an InAs wafer and two neodymium magnets. The emitter was irradiated by femtosecond laser pulses. The data quality of terahertz spectroscopic measurements was evaluated, and reduction of error in the data obtained due to the terahertz power enhancement was observed.

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Yano, Kaori, et Toshiaki Hattori. « Improving a Terahertz Time-Domain Spectroscopy Apparatus Using Neodymium Magnets ». International Letters of Chemistry, Physics and Astronomy 62 (27 novembre 2015) : 10–14. http://dx.doi.org/10.56431/p-cw453x.

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The signal-to-noise ratio obtained from terahertz time-domain spectroscopy is significantly affected by the low available power of terahertz waves. We constructed a terahertz-wave source with emission power enhanced by a magnetic field. The emitter is composed of an InAs wafer and two neodymium magnets. The emitter was irradiated by femtosecond laser pulses. The data quality of terahertz spectroscopic measurements was evaluated, and reduction of error in the data obtained due to the terahertz power enhancement was observed.

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16

Mark, Howard L., et Peter R. Griffiths. « Analysis of Noise in Fourier Transform Infrared Spectra ». Applied Spectroscopy 56, n^o 5 (mai 2002) : 633–39. http://dx.doi.org/10.1366/0003702021955196.

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The currently accepted theory of spectroscopic noise causes most spectroscopists to accept the statement that when the limiting noise source is constant detector noise (e.g., as in mid- and near-IR spectroscopy) the noise of a transmittance spectrum is also constant, and independent of the sample transmittance. A careful examination of the effect of noise on spectra, however, reveals that most of the previous derivations have neglected the effect of noise in the reference reading on the noise content of the spectra. The consequences range from the fact that even with constant detector noise, the error of a transmittance spectrum is NOT constant, to the fact that the optimum value of sample transmittance, to obtain best relative precision, is not 36.8%, as usually stated, but 33%. We also present the results of experiments performed to distinguish between the results predicted by the two theories and to verify that taking the reference noise into account does, in fact, make a difference. “The trouble with the world is not that people know too little, it's that they know so many things that ain't so.” (Mark Twain)

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Yuzawa, Tetsuro, Chihiro Kato, Michael W. George et Hiro-O. Hamaguchi. « Nanosecond Time-Resolved Infrared Spectroscopy with a Dispersive Scanning Spectrometer ». Applied Spectroscopy 48, n^o 6 (juin 1994) : 684–90. http://dx.doi.org/10.1366/000370294774368947.

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A nanosecond time-resolved infrared spectroscopic system based on a dispersive scanning spectrometer has been constructed. This is an advanced version of a similar system reported in a previous paper; the time resolution has been improved from 1 μs to 50 ns and the sensitivity from 10−4 in intensity changes to 10−6. These have been achieved by the use of a high-temperature ceramic infrared light source, a photovoltaic MCT detector, and a low-noise, wide-band preamplifier developed specifically for the present purpose. Time-resolved infrared spectra of a few samples of photochemical and photobiological interests are presented to show the capability of the system. The origin of the thermal artifacts, which have been found to hamper the time-resolved infrared measurements seriously, is shown to be due to the transient reflectance change induced by a small temperature jump. The future prospect of time-resolved infrared spectroscopy is discussed with reference to other methods including infrared laser spectroscopy and Fourier transform infrared spectroscopy.

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Drexler, Petr, Pavel Fiala, Radim Kadlec et Radek Kubasek. « The Instruments for Noise Spectroscopy ». PIERS Online 6, n^o 7 (2010) : 609–12. http://dx.doi.org/10.2529/piers091218085414.

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Harsh, Rishav, et K. S. Narayan. « Noise spectroscopy of polymer transistors ». Journal of Applied Physics 118, n^o 20 (28 novembre 2015) : 205502. http://dx.doi.org/10.1063/1.4936197.

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Römer, M., J. Hübner et M. Oestreich. « Spin noise spectroscopy in semiconductors ». Review of Scientific Instruments 78, n^o 10 (octobre 2007) : 103903. http://dx.doi.org/10.1063/1.2794059.

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21

Rosenbluh, M., A. Rosenhouse-Dantsker, A. D. Wilson-Gordon, M. D. Levenson et R. Walser. « Spectroscopy with diode-laser noise ». Optics Communications 146, n^o 1-6 (janvier 1998) : 158–62. http://dx.doi.org/10.1016/s0030-4018(97)00485-9.

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Aroutiounian, Vladimir M., Zara H. Mkhitaryan, Arkady A. Shatveryan, Ferdinand V. Gasparyan, Mher Zh Ghulinyan, Lorenzo Pavesi, Laszlo B. Kish et Claes-GÖran Granqvist. « Noise Spectroscopy of Gas Sensors ». IEEE Sensors Journal 8, n^o 6 (juin 2008) : 786–90. http://dx.doi.org/10.1109/jsen.2008.923184.

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Pershin, Yuriy V., Valeriy A. Slipko, Dibyendu Roy et Nikolai A. Sinitsyn. « Two-beam spin noise spectroscopy ». Applied Physics Letters 102, n^o 20 (20 mai 2013) : 202405. http://dx.doi.org/10.1063/1.4807011.

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Yang, D. K., et D. B. Zax. « Bandwidth Extension in Noise Spectroscopy ». Journal of Magnetic Resonance 135, n^o 1 (novembre 1998) : 267–70. http://dx.doi.org/10.1006/jmre.1998.1577.

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Starchev, Konstantin, Jaro Ricka et Jacques Buffle. « Noise on Fluorescence Correlation Spectroscopy ». Journal of Colloid and Interface Science 233, n^o 1 (janvier 2001) : 50–55. http://dx.doi.org/10.1006/jcis.2000.7229.

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Shih, Wei-Chuan. « Constrained regularization for noninvasive glucose sensing using Raman spectroscopy ». Journal of Innovative Optical Health Sciences 08, n^o 04 (juillet 2015) : 1550022. http://dx.doi.org/10.1142/s1793545815500224.

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Multivariate calibration is an important tool for spectroscopic measurement of analyte concentrations. We present a detailed study of a hybrid multivariate calibration technique, constrained regularization (CR), and demonstrate its utility in noninvasive glucose sensing using Raman spectroscopy. Similar to partial least squares (PLS) and principal component regression (PCR), CR builds an implicit model and requires knowledge only of the concentrations of the analyte of interest. Calibration is treated as an inverse problem in which an optimal balance between model complexity and noise rejection is achieved. Prior information is included in the form of a spectroscopic constraint that can be obtained conveniently. When used with an appropriate constraint, CR provides a better calibration model compared to PLS in both numerical and experimental studies.

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Janot-Pacheco, Eduardo, et Nelson Vani Leister. « Seismology of southern Be stars ». Symposium - International Astronomical Union 162 (1994) : 104–5. http://dx.doi.org/10.1017/s0074180900214630.

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We have started in 1990 a search for moving bumps in the HeI λ 667.8 nm of mainly southern, bright Be stars. The objects of our sample have been selected on the basis of photometric variability (Cuypers et al., 1989). High resolution (R≥ 30,000), high signal-to-noise ratio (S/R≥ 300) spectroscopic observations have been performed at the brazilian Laboratório Nacional de Astrofísica with a CCD camera attached to the coudé spectrograph of the 1.60 m telescope (e.g. Table I). Several hundred spectra have been taken during the last three years. Photometric observations simultaneous with spectroscopy were made on the same site in July 1992 with a two-channel photometer (Stromgren b filter) and a CCD camera (Johnson B filter) installed at two 0.60 m telescopes. The idea is try to disentangle the controversy between NRP and RM models with the help of simultaneous spectroscopy and photometry.

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Stadler, Adam, et Andrzej Dziedzic. « Virtual instruments in low-frequency noise spectroscopy experiments ». Facta universitatis - series : Electronics and Energetics 28, n^o 1 (2015) : 17–28. http://dx.doi.org/10.2298/fuee1501017s.

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Low-frequency noise spectroscopy (LFNS) is an experimental technique to study noise spectra, typically below 10 kHz, as a function of temperature. Results of LFNS may be presented as the ?so-called? noise maps, giving a detailed insight into fluctuating phenomena in electronic devices and materials. The authors show the usefulness of virtual instrument concept in developing and controlling the measurement setup for LFNS experiments. An example of a noise map obtained for polymer thick-film resistors (PTFRs), made of commercial compositions, for temperature range 77 K - 300 K has been shown. The experiments proved that 1/f noise caused by resistance fluctuations is the dominant noise component in the studied samples. However, the obtained noise map revealed also thermally activated noise sources. Furthermore, parameters describing noise properties of resistive materials and components have been introduced and calculated using data from LFNS. The results of the work may be useful for comparison of noise properties of different resistive materials, giving also directions for improvement of thick-film technology in order to manufacture reliable, low-noise and stable PTFRs.

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Wang, Xing-Ping, Gang Zhao, Kang Jiao, Bing Chen, Rui-Feng Kan, Jian-Guo Liu et Wei-Guang Ma. « Uncertainty of optical feedback linear cavity ringdown spectroscopy ». Acta Physica Sinica 71, n^o 12 (2022) : 124201. http://dx.doi.org/10.7498/aps.70.20220186.

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Cavity ring-down spectroscopy (CRDS) is a highly sensitive molecular absorption spectroscopic technology, which has been widely used in mirror reflectance measurement, atmospheric trace gas detection, molecular precision spectroscopy and other fields. It deduces the intracavity absorption by measuring the rapid variation of the ringdown signal. As a result, detector with high linearity, broad bandwidth and low electrical noise is indispensable. Additionally, owing to the large noise in laser frequency, low laser-to-cavity coupling efficiency is obtained. Consequently, the cavity transmission is faint, which deteriorates the detection sensitivity. Optical feedback can address this problem by locking the laser to the cavity longitudinal mode. Then, the laser frequency noise is suppressed and hence better detection sensitivity is expected. Optical feedback CRDS with V-shape cavity has been widely studied. Compared with Fabry-Perot cavity, this cavity geometry is very sensitive to mechanical vibration and possesses low degree of fineness due to an additional mirror. In this paper, optical feedback linear cavity ring-down spectroscopy based on a Fabry-Perot cavity with a degree of fineness of 7800 is presented. The principle of the combination of optical feedback and linear cavity is explained from the perspective of the light phase, which shows that the reflection will not generate efficient optical feedback if the feedback phase is appropriately controlled and laser to cavity locking can be therefore realized. And then, the factors influencing the stability of ring-down signal are analyzed, including the feedback ratio, the trigger voltage for the ringdown event, and the distance between the light spot and the detector center. The experimental results show that a superior fractional uncertainty of the empty ringdown time of 0.026% can be obtained with a low feedback rate (3% FSR), a high ringdown signal trigger threshold (90% cavity mode amplitude) and superposition of the light spot with the detector center. With Allan variance analysis, the white noise response of 1.56 × 10<sup>–9</sup> cm<sup>–1</sup>/ Hz<sup>–1/2</sup> and the detection sensitivity of 1.29 × 10<sup>–10</sup> cm<sup>–1</sup> for trace gas detection can be achieved in an integration time of 180 s, corresponding to the lowest CH<sub>4</sub> concentration detection of 0.35 ppb at 6046.9 cm<sup>–1</sup>. This robust spectroscopic technique paves the way for constructing high-sensitive and stable-cavity based instrument for trace gas detection.

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Kim, Youngsang, et Hyunwook Song. « Noise spectroscopy of molecular electronic junctions ». Applied Physics Reviews 8, n^o 1 (mars 2021) : 011303. http://dx.doi.org/10.1063/5.0027602.

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Nadezhdinskii, A. I., Ya Ya Ponurovskii, D. B. Stavrovskii et Yu P. Shapovalov. « Flicker Noise in Diode Laser Spectroscopy ». Physics of Wave Phenomena 28, n^o 4 (octobre 2020) : 362–68. http://dx.doi.org/10.3103/s1541308x20040093.

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LI Chen, 李晨, 丁畅 DING Chang, 张桐耀 ZHANG Tong-yao, 曹丹华 CAO Dan-hua, 吴裕斌 WU Yu-bin et 陈院森 CHEN Yuan-sen. « Tunable High-speed Spin Noise Spectroscopy ». Acta Sinica Quantum Optica 23, n^o 3 (2017) : 228–31. http://dx.doi.org/10.3788/jqo20172303.0003.

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McIntyre, D. H., J. Cooper, R. Walser et C. E. Fairchild. « Diode-laser noise spectroscopy of rubidium ». Optics Letters 18, n^o 21 (1 novembre 1993) : 1816. http://dx.doi.org/10.1364/ol.18.001816.

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DiNitto, Julie M., et John M. Kenney. « Noise Characterization in Circular Dichroism Spectroscopy ». Applied Spectroscopy 66, n^o 2 (février 2012) : 180–87. http://dx.doi.org/10.1366/11-06417.

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Kim, Youngsang, et Hyunwook Song. « Noise spectroscopy of molecular electronic junctions ». Applied Physics Reviews 8, n^o 1 (mars 2021) : 011303. http://dx.doi.org/10.1063/5.0027602.

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Vemuri, Gautam. « Noise spectroscopy of randomly modulated atoms ». Journal of Chemical Physics 115, n^o 21 (décembre 2001) : 9912–22. http://dx.doi.org/10.1063/1.1416869.

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Misono, M., H. Fujimoto, T. Kohmoto, Y. Fukuda et M. Kunitomo. « Correlation spectroscopy with noise light excitation ». Physics Letters A 240, n^o 1-2 (mars 1998) : 29–36. http://dx.doi.org/10.1016/s0375-9601(98)00043-7.

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Madenach, Armin J., et Jürgen H. Werner. « Noise spectroscopy of silicon grain boundaries ». Physical Review B 38, n^o 18 (15 décembre 1988) : 13150–62. http://dx.doi.org/10.1103/physrevb.38.13150.

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Kohmoto, T., T. Murakami, Y. Fukuda et M. Kunitomo. « Noise excitation spectroscopy in Rb atoms ». Progress in Crystal Growth and Characterization of Materials 33, n^o 1-3 (janvier 1996) : 367–70. http://dx.doi.org/10.1016/0960-8974(96)83673-4.

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Grafov, B. M., Yu A. Dobrovolskii, A. L. Klyuev, A. E. Ukshe, A. D. Davydov et E. A. Astaf’ev. « Median Chebyshev spectroscopy of electrochemical noise ». Journal of Solid State Electrochemistry 21, n^o 3 (6 octobre 2016) : 915–18. http://dx.doi.org/10.1007/s10008-016-3395-0.

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Kozlov, G. G. « Noise spectroscopy of an optical microresonator ». Journal of Experimental and Theoretical Physics 116, n^o 5 (mai 2013) : 749–54. http://dx.doi.org/10.1134/s1063776113040055.

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Greenhalgh, D. A., et S. T. Whittley. « Mode noise in broadband CARS spectroscopy ». Applied Optics 24, n^o 6 (15 mars 1985) : 907. http://dx.doi.org/10.1364/ao.24.000907.

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Fiala, Pavel, Petr Drexler, Dusan Nespor, Zoltan Szabo, Jan Mikulka et Jiri Polivka. « The Evaluation of Noise Spectroscopy Tests ». Entropy 18, n^o 12 (10 décembre 2016) : 443. http://dx.doi.org/10.3390/e18120443.

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Abdullaev, N. T., O. A. Dyshin et M. M. Gasankulieva. « Flicker Noise Spectroscopy of Electrocardiographic Signals ». Biomedical Engineering 49, n^o 5 (janvier 2016) : 268–73. http://dx.doi.org/10.1007/s10527-016-9546-x.

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BENZINE, Malika. « Infrared Spectroscopy Analysis of Kidney Stones : Methodology of Identification ». Clinical Trials and Bioavailability Research 2, n^o 1 (28 février 2023) : 01–03. http://dx.doi.org/10.58489/2836-5836/006.

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The urinary stone analysis is the first step in looking for the causes of urolithiasis, in order to avoid the problems of recurrence. This analysis sometimes makes it possible to propose a diagnosis, and most often helps to direct the exploration towards the most appropriate examinations. To be reliable, the identification of the components of urinary stones must be carried out by infrared spectroscopy. This study made it possible to make a profile approach on a case of a 67-year-old male adult patient, hospitalized in the urology department of the Bechar hospital (Algeria). Morpho-constitutional analysis of urinary stones showed that the main component was calcium oxalate monohydrate (whewellite) with a percentage of (70%), weddellite (20%), carbapatite (10%), and trace protein. According to the results obtained we notice that the periphery of the stone is Wheddellite, and the nucleus formed essentially of: Whewellite + CA + trace of Protein. According to the superficial and internal morphological type and the morphological association, we can distinguish the main causes that go into the formation of stones: intermittent hypercalciuria (nutritional or absorptive) + intermittent hyperoxaluria (normal or slightly increased oxaluria), these results allow more specific medical management of lithiasis and better prevention of recurrent problems.

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Ishiguro, Nozomu, et Yukio Takahashi. « Method for restoration of X-ray absorption fine structure in sparse spectroscopic ptychography ». Journal of Applied Crystallography 55, n^o 4 (1 août 2022) : 929–43. http://dx.doi.org/10.1107/s1600576722006380.

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The spectroscopic ptychography method, a technique combining X-ray ptychography imaging and X-ray absorption spectroscopy, is one of the most promising and powerful tools for studying the chemical states and morphological structures of bulk materials at high resolutions. However, this technique still requires long measurement periods because of insufficient coherent X-ray intensity. Although the improvements in hardware represent a critical solution, breakthroughs in software for experiments and analyses are also required. This paper proposes a novel method for restoring the spectrum structures from spectroscopic ptychography measurements with reduced energy points, by utilizing the Kramers–Kronig relationship. First, a numerical simulation is performed of the spectrum restoration for the extended X-ray absorption fine structure (EXAFS) oscillation from the thinned theoretical absorption and phase spectra. Then, this algorithm is extended by binning the noise removal to handle actual experimental spectral data. Spectrum restoration for the experimental EXAFS data obtained from spectroscopic ptychography measurements is also successfully demonstrated. The proposed restoration will help shorten the time required for spectroscopic ptychography single measurements and increase the throughput of the entire experiment under limited time resources.

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Faguy, Peter W., William N. Richmond, Richard S. Jackson, Stephen C. Weibel, Gail Ball et Joe H. Payer. « Real-Time Polarization Modulation in Situ Infrared Spectroscopy Applied to the Study of Atmospheric Corrosion ». Applied Spectroscopy 52, n^o 4 (avril 1998) : 557–64. http://dx.doi.org/10.1366/0003702981943879.

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A new methodology for the real-time in situ monitoring of atmospheric corrosion processes is presented. The mid-infrared spectra of surface films formed on polished copper substrates exposed to humid air containing sub-ppm levels of sulfur dioxide, nitric oxide, and hydrogen chloride were obtained by using a novel surface-sensitive infrared technique: real-time polarization modulation grazing angle reflection-absorption spectroscopy. The new methodology demonstrated improved signal-to-noise ratios, by a factor of 2.5, as compared to conventional Fourier transform infrared reflection absorption spectroscopy. Molecular spectroscopic data for water- and hydroxyl-containing species present at the metal surface were obtained with no interference from water vapor. Over the spectral region 4000–800 cm−1, bands were identified and assigned to nitro and nitrito adsorbates, to sulfite ions, and to bound water on the copper surface. Analysis of the time evolution and the profile composition of these bands is possible because of the sensitivity of this new optical sampling technique.

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Kasapi, Steven, Seema Lathi et Yoshihisa Yamamoto. « Sub-shot-noise FM noise spectroscopy of trapped rubidium atoms ». Journal of the Optical Society of America B 15, n^o 10 (1 octobre 1998) : 2626. http://dx.doi.org/10.1364/josab.15.002626.

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Kolar, Petar, Lovro Blažok et Dario Bojanjac. « How (and why) to determine NMR spectrometer’s noise figure ? » tm - Technisches Messen 87, n^o 10 (25 octobre 2020) : 614–21. http://dx.doi.org/10.1515/teme-2020-0043.

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AbstractIn the last decade or two, it seems that the trend of technological advance in NMR spectroscopy cannot follow the trend of desire to measure NMR samples with gradually lower response signals. Recently, an accurate noise model, based on the concept of noise figure, of the most sensitive part of the NMR spectroscopy system from the aspect of noise, which is its probe-to-spectrometer receiving chain, was introduced. The main purpose of this model is to optimize the used NMR spectroscopy system and, ultimately, enable measuring NMR samples with even lower response signals than the ones measured today. All the parameters of the NMR spectroscopy system, used in the introduced model, can be easily measured using vector network analyzers and noise figure meters, or can be found in the datasheets of the respective elements, except the spectrometer’s receiving chain noise figure. In this contribution, the process of spectrometer’s receiving chain noise figure measurement, performed using the Twice Power Method, is described. A block diagram representation of the spectrometer’s receiving chain is presented here, as well as its approximative model. The respective noise figure measurement results, which are also presented, explain the general tendency of using the mid-range of the spectrometer’s gain control level when performing the actual NMR measurements.

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Zubrzycka, W., et P. Grybos. « Optimization of low-noise read-out electronics for high energy resolution X-ray strip detectors ». Journal of Instrumentation 18, n^o 01 (1 janvier 2023) : C01033. http://dx.doi.org/10.1088/1748-0221/18/01/c01033.

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Abstract Semiconductor strip sensors applied as solid-state radiation or particle detectors can be used in radiation detection and measurement for various applications in particle physics experiments, X-ray imaging (e.g. medical), or material science. The X-ray imaging devices with spectroscopic and position resolution features are a very important research topic at many institutes and companies worldwide. Short strip silicon detectors are good candidates for X-ray spectroscopy, because of their relatively small capacitance and leakage current. If additionally, strip pitch is below 100 μm, then the high spatial resolution is also possible. In this paper, the analysis and noise optimization of the read-out electronics for short silicon strip detectors with Charge Sensitive Amplifier (CSA) and shaping amplifier (shaper) is presented. The CSA is optimized for the detector capacitance of around 1.5 pF, and the shaper nominal peaking time is about 1 μs (controlled by the sets of switches). We take into account the sources of noise in a radiation imaging system (current parallel noise, voltage series noise, and 1/f or flicker series noise) both internal (related to the front-end electronics itself) but also external, stemming from a sensor, interconnect, or printed circuit board parasitic components. We target the noise level below 40 el. rms, considering low power consumption (a few mW) and limited channel area.

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