Optical path length and absorption cross section optimization for high sensitivity ozone concentration measurement

2015 ◽  
Vol 221 ◽  
pp. 570-575 ◽  
Author(s):  
Tay Ching En Marcus ◽  
Mohd Haniff Ibrahim ◽  
Nor Hafizah Ngajikin ◽  
Asrul Izam Azmi
Keyword(s):  
Cross Section ◽  
Ozone Concentration ◽  
Absorption Cross Section ◽  
Path Length ◽  
High Sensitivity ◽  
Optical Path Length ◽  
Optical Path ◽  
Concentration Measurement ◽  
Absorption Cross

Interchangeable Range of Ozone Concentration Simulation for Low Cost Reconfigurable Brass Gas Cell

2014 ◽  
Vol 69 (8) ◽  
Author(s):  
Tay Ching En Marcus ◽  
Michael David ◽  
Maslina Yaacob ◽  
Mohd Rashidi Salim ◽  
Mohd Haniff Ibrahim ◽  
...  
Keyword(s):  
Theoretical Calculation ◽  
Ozone Concentration ◽  
Path Length ◽  
Low Cost ◽  
Cell Structure ◽  
Optical Path Length ◽  
Optical Path ◽  
Concentration Measurement ◽  
Gas Cell ◽  
Wide Range

Ultraviolet absorption spectroscopy is reliable for ozone concentration measurement. Concentration range and optical path length are inversely related based on theoretical calculation and observation of previous work. However, gas cells for ozone application are typically not expandable. In addition, they incur cost for custom fabrication. Here we design a reconfigurable brass gas cell that may interchange optical path length between 5.6 cm and 10.8 cm. Components are available at low cost, easy to joint and ready to use. Theoretical background and gas cell structure are discussed. Practical transmittance values between e-0.65 and e-0.05 are proposed for theoretical calculation of concentration via Beer-Lambert law. The concentration values are used in SpectralCalc.com gas cell simulation to obtain transmittance. Both approaches yield comparable result. Simulation result shows concentration range of 5.6 cm optical path length gas cell (31.82 ppm to 413.67 ppm) is wider than concentration range of 10.8 cm optical path length gas cell (16.50 ppm to 214.49 ppm). Simulation condition is at transmittance from 0.5291 to 0.9522, sampling wavelength 253.65 nm, temperature 300 K and pressure 1 atm. Thus, we strongly recommend short optical path length gas cell (5.6 cm) for wide range of concentration measurement (31.82 ppm to 413.67 ppm).

Applications of Optical Path Length Compensation Technology for High Power CO2 Laser Cutting Process

2014 ◽  
Vol 939 ◽  
pp. 177-185
Author(s):  
Zhao Chi Chen ◽  
Liang Ju Pan
Keyword(s):  
Cross Section ◽  
Laser Cutting ◽  
Path Length ◽  
Cutting Speed ◽  
Optical Path Length ◽  
Spot Size ◽  
Optical Path ◽  
Cutting Process ◽  
Focus Position ◽  
The Cross

High powerCO2(Carbon Dioxide,CO2) laser cutting process not only attention to the type of material selected, the focus position of the laser beam and spot size (beam size) also plays an important role. In this paper, metal materials cutting through the wavelength of 10.6μm,CO2 laser with the optical path length compensation techniquewith output power 4000W. We compare different focus position and spot size for processing quality to discussing the use of a constant optical path length system to maintain the stability of the cross-section of the metal material after laser cutting.Optical path length compensation is used with ABCD Law in metal (steel) laser cutting processing an indispensable technology.Finally, we verify that the cross-section of the optical path length compensation under laser cutting in different processing location, thicknessof 16 mmsteel with laser power 4000W, and cutting speed 0.9 m/minconditions observed area 3*1.5 m2workingstagefor optical path length of 7, 8.5, 10 and 11.5 m,the steel ofcross-section appearance almost identical.

scholarly journals Varying Effects of Temperature and Path-length on Ozone Absorption Cross-Section

2018 ◽  
Vol 16 (2) ◽  
pp. 618
Author(s):  
Enenche Patrick ◽  
Michael David ◽  
A.O. Caroline ◽  
Mohd Haniff Ibrahim ◽  
Sevia Mahdaliza Idrus ◽  
...  
Keyword(s):  
Cross Section ◽  
Absorption Cross Section ◽  
Path Length ◽  
Absorption Cross ◽  
Ozone Absorption ◽  
Effects Of Temperature

Development of a MEMS Xylophone Bar Magnetometer Using Optical Interferometry for Detection

1999 ◽  
Vol 605 ◽  
Author(s):  
Joseph Miragliotta ◽  
R. Osiander ◽  
J. L. Champion ◽  
D. A. Oursler ◽  
T.J. Kistenmacher
Keyword(s):  
Magnetic Field ◽  
Path Length ◽  
Dynamic Range ◽  
Michelson Interferometer ◽  
High Sensitivity ◽  
Force Sensor ◽  
Optical Path Length ◽  
Optical Path ◽  
Active Stabilization ◽  
Path Length Difference

AbstractWe report the results of an optical interferometric study, which was designed to measure the magnetic-field induced displacement of a resonating xylophone bar MEMS magnetometer. The MEMS magnetometer is a Lorentz-force sensor, which transduces an alternating current and an orthogonal directed magnetic field into an alternating displacement of the xylophone bar. The Michelson interferometer system includes optics and electronics for active stabilization of the optical path length difference between the reference and sample beams. The active stabilization results in the ability to control or detect pathlength differences as small as ∼ 0.6 ×10−3 Å. With this level of operational sensitivity, the presence of a one nano Tesla magnetic field was found to produce a detectable bar displacement on the order of ∼10−3 Å. In addition to the high sensitivity, the interferometer photodetector displayed linear behavior over six decades of optical path length differences, which corresponded to a magnetic field dynamic range that spanned nano- to milli-Tesla amplitudes.

Pressure Dependence of Ozone Absorption Cross Section

2015 ◽  
Vol 735 ◽  
pp. 260-264
Author(s):  
Tay Ching En Marcus ◽  
Michael David ◽  
Maslina Yaacob ◽  
Mohd Rashidi Salim ◽  
Nabihah Hussin ◽  
...  
Keyword(s):  
Cross Section ◽  
Ozone Concentration ◽  
Pressure Dependence ◽  
Absorption Cross Section ◽  
Maximum Absorption ◽  
Absorption Cross ◽  
Ozone Absorption ◽  
Pressure Changes ◽  
Maximum Absorption Wavelength ◽  
Absorption Wavelength

Accurate value of absorption cross section is required for correct measurement of ozone concentration. Measurement of ozone has been done at different altitude and pressure. However, previous work has failed to establish significant relation between pressure and ozone absorption cross section. Therefore, this work aims to establish relation between pressure and maximum ozone absorption cross section via spectralcalc.com gas cell simulator. Simulation results show maximum absorption cross section 1.148×10-21 m2 molecule-1 and maximum absorption wavelength 255.442 nm are independent of pressure changes from 0.1 atm to 3.0 atm. Thus, measurement of ozone concentration at maximum absorption wavelength is strongly recommended due to negligible pressure dependence.

Investigation of particulate systems using optical pathlength spectroscopy

2000 ◽  
Vol 627 ◽  
Author(s):  
Gabriel Popescu ◽  
Aristide Dogariu
Keyword(s):  
Path Length ◽  
Random Media ◽  
Michelson Interferometer ◽  
Industrial Process ◽  
Optical Path Length ◽  
Industrial Applications ◽  
Optical Path ◽  
Interference Signal ◽  
Optical Length ◽  
Reference Mirror

ABSTRACTIn many industrial applications involving granular media, knowledge about the structural transformations suffered during the industrial process is desirable. Optical techniques are noninvasive, fast, and versatile tools for monitoring such transformations. We have recently introduced optical path-length spectroscopy as a new technique for random media investigation. The principle of the method is to use a partially coherent source in a Michelson interferometer, where the fields from a reference mirror and the sample are combined to obtain an interference signal. When the system under investigation is a multiple-scattering medium, by tuning the optical length of the reference arm, the optical path-length probability density of light backscattered from the sample is obtained. This distribution carries information about the structural details of the medium. In the present paper, we apply the technique of optical path-length spectroscopy to investigate inhomogeneous distributions of particulate dielectrics such as ceramics and powders. The experiments are performed on suspensions of systems with different solid loads, as well as on powders and suspensions of particles with different sizes. We show that the methodology is highly sensitive to changes in volume concentration and particle size and, therefore, it can be successfully used for real-time monitoring. In addition, the technique is fiber optic-based and has all the advantages associated with the inherent versatility.

scholarly journals Photoelectric absorption cross section of silicon near the bandgap from room temperature to sub-Kelvin temperature

AIP Advances ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 025120
Author(s):  
C. Stanford ◽  
M. J. Wilson ◽  
B. Cabrera ◽  
M. Diamond ◽  
N. A. Kurinsky ◽  
...  
Keyword(s):  
Cross Section ◽  
Absorption Cross Section ◽  
Room Temperature ◽  
Absorption Cross ◽  
Photoelectric Absorption

scholarly journals Stray light characterization with ultrafast time-of-flight imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
L. Clermont ◽  
W. Uhring ◽  
M. Georges
Keyword(s):  
Path Length ◽  
Imaging System ◽  
Time Of Flight ◽  
Optical Path Length ◽  
Optical Path ◽  
Stray Light ◽  
Laser Source ◽  
Space Telescopes ◽  
Characterization Methods ◽  
Instance Space

AbstractUnderstanding stray light (SL) is a crucial aspect in the development of high-end optical instruments, for instance space telescopes. As it drives image quality, SL must be controlled by design and characterized experimentally. However, conventional SL characterization methods are limited as they do not provide information on its origins. The problem is complex due to the diversity of light interaction processes with surfaces, creating various SL contributors. Therefore, when SL level is higher than expected, it can be difficult to determine how to improve the system. We demonstrate a new approach, ultrafast time-of-flight SL characterization, where a pulsed laser source and a streak camera are used to record individually SL contributors which travel with a specific optical path length. Furthermore, the optical path length offers a means of identification to determine its origin. We demonstrate this method in an imaging system, measuring and identifying individual ghosts and scattering components. We then show how it can be used to reverse-engineer the instrument SL origins.

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