Configuration of ring-down spectrometers for maximum sensitivity

2004 ◽  
Vol 82 (6) ◽  
pp. 873-879 ◽  
Author(s):  
Michael Jakubinek ◽  
Zhaoguo Tong ◽  
Sergei Manzhos ◽  
Hans-Peter Loock
Keyword(s):  
Detection Limit ◽  
Gas Phase ◽  
Cavity Length ◽  
High Sensitivity ◽  
Relative Sensitivity ◽  
Time Measurement ◽  
Design Requirements ◽  
Loop Ring ◽  
Cavity Ring Down ◽  
Fiber Loop

Cavity ring-down (CRD) spectrometers used for analytical applications frequently have design requirements different from spectrometers used for gas-phase spectroscopic applications. A formalism that allows for maximization of the relative sensitivity by adapting the cavity length and absorption path through the sample is presented. These experimental configurations may not reduce the detection limit but do allow for a high sensitivity of the ring-down time measurement in the concentration range of interest. The formalism is applied to two common CRDS experimental configurations and to a fiber-loop ring-down experiment.Key words: cavity ring-down (CRD), absorption, detector, fiber-loop, sensitivity, detection limit.

A Torsion Relative Angle Measurement Method Based on Fiber-Loop Ring-Down with Intra-Cavity Amplification

2021 ◽  
Vol 13 ◽  
Author(s):  
Tao Ma ◽  
Yongsheng Tian ◽  
Shaohui Liu ◽  
Jiahe Ma ◽  
Heng Liu ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Measurement Method ◽  
Polarization State ◽  
High Sensitivity ◽  
Angle Measurement ◽  
Relative Angle ◽  
Low Sensitivity ◽  
Loop Ring ◽  
Light Fluctuation ◽  
Fiber Loop

Background: The fiber-loop ring-down spectroscopy technique has the benefits of optical fiber sensors and also has many unique advantages. Combined with various sensor structures, the FLRD system can achieve different physical, chemical, and biological sensors. Objective: To find a way to solve the problems of light fluctuation and low sensitivity, a high sensitivity and reliability torsion relative angle measurement system is necessary. Methods: The torsion relative angle measurement is achieved by using the fiber loop ring-down intra-cavity amplification. The sensitivity, correlation coefficient, and repeatability are analyzed with the experiment. Results: The sensitivity and correlation coefficient of the proposed system are 4.05 μs/° and 0.9996, respectively. The repeated experiments show that the standard deviation is 9.592×10-4. Conclusion: The proposed measurement method provides a way to solve the problems of light fluctuation and low sensitivity and has promising applications in the optically active solutions, fiber radial stress birefringence, and polarization state measurement of fiber lasers.

High sensitivity pressure sensor based on a simple SPS fiber loop mirror

2021 ◽  
Vol 53 (8) ◽  
Author(s):  
Hanglin Lu ◽  
Yalan Niu ◽  
Jian Tang ◽  
Li Yang ◽  
Laipeng Shao ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
High Sensitivity ◽  
Fiber Loop Mirror ◽  
Loop Mirror ◽  
Fiber Loop

scholarly journals Novel gas sensor combined active fiber loop ring-down and dual wavelengths differential absorption method

2014 ◽  
Vol 22 (9) ◽  
pp. 11244 ◽  
Author(s):  
Yanjie Zhao ◽  
Jun Chang ◽  
Jiasheng Ni ◽  
Qingpu Wang ◽  
Tongyu Liu ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Absorption Method ◽  
Differential Absorption ◽  
Active Fiber ◽  
Loop Ring ◽  
Differential Absorption Method ◽  
Fiber Loop

High sensitivity CW-Cavity Ring Down Spectroscopy of N2O near 1.5μm (II)

2007 ◽  
Vol 244 (1) ◽  
pp. 48-62 ◽  
Author(s):  
A.W. Liu ◽  
S. Kassi ◽  
V.I. Perevalov ◽  
S.A. Tashkun ◽  
A. Campargue
Keyword(s):  
High Sensitivity ◽  
Cavity Ring Down Spectroscopy ◽  
Cavity Ring Down

scholarly journals Plasmonic Sensing Studies of a Gas-Phase Cystic Fibrosis Marker in Moisture Laden Air

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3776
Author(s):  
Libin Sun ◽  
Douglas Conrad ◽  
Drew A. Hall ◽  
Kurt D. Benkstein ◽  
Steve Semancik ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Detection Limit ◽  
Gas Phase ◽  
Localized Surface Plasmon ◽  
Exhaled Breath ◽  
Nanohole Array ◽  
Dry Air ◽  
Plasmonic Sensing ◽  
Sensing Platform ◽  
The Status

A plasmonic sensing platform was developed as a noninvasive method to monitor gas-phase biomarkers related to cystic fibrosis (CF). The nanohole array (NHA) sensing platform is based on localized surface plasmon resonance (LSPR) and offers a rapid data acquisition capability. Among the numerous gas-phase biomarkers that can be used to assess the lung health of CF patients, acetaldehyde was selected for this investigation. Previous research with diverse types of sensing platforms, with materials ranging from metal oxides to 2-D materials, detected gas-phase acetaldehyde with the lowest detection limit at the µmol/mol (parts-per-million (ppm)) level. In contrast, this work presents a plasmonic sensing platform that can approach the nmol/mol (parts-per-billion (ppb)) level, which covers the required concentration range needed to monitor the status of lung infection and find pulmonary exacerbations. During the experimental measurements made by a spectrometer and by a smartphone, the sensing examination was initially performed in a dry air background and then with high relative humidity (RH) as an interferent, which is relevant to exhaled breath. At a room temperature of 23.1 °C, the lowest detection limit for the investigated plasmonic sensing platform under dry air and 72% RH conditions are 250 nmol/mol (ppb) and 1000 nmol/mol (ppb), respectively.

Porous ZnO/rGO Nanosheet‐Based NO 2 Gas Sensor with High Sensitivity and ppb‐Level Detection Limit at Room Temperature

2021 ◽  
pp. 2101511
Author(s):  
Ziwei Chen ◽  
Haojie Guo ◽  
Fusheng Zhang ◽  
Xiaowen Li ◽  
Jiabing Yu ◽  
...  
Keyword(s):  
Detection Limit ◽  
Gas Sensor ◽  
Room Temperature ◽  
High Sensitivity

scholarly journals A Highly Sensitive, Polarization Maintaining Photonic Crystal Fiber Sensor Operating in the THz Regime

Photonics ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 40 ◽  
Author(s):  
Sohel Rana ◽  
Nirmala Kandadai ◽  
Harish Subbaraman
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystal Fiber ◽  
High Sensitivity ◽  
Relative Sensitivity ◽  
Computational Technique ◽  
The Finite Element Method ◽  
High Birefringence ◽  
Crystal Fiber ◽  
Highly Sensitive ◽  
Imaging And Spectroscopy

In this paper, a high sensitivity, polarization preserving photonic crystal fiber (PCF), based on circular air holes for sensing in the terahertz (THz) band, is presented. The finite element method, a practical and precise computational technique for describing the interactions between light and matter, is used to compute the modal properties of the designed fiber. For the designed PCF, comprising of circular air holes in both the cladding and in the porous core, a relative sensitivity of 73.5% and a high birefringence of 0.013 are achieved at 1.6 THz. The all circular air-hole structure, owing to its simplicity and compatibility with the current fiber draw technique for PCF fabrication, can be realized practically. It is anticipated that the designed fiber can be employed in applications such as detection of biological samples and toxic chemicals, imaging, and spectroscopy.

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