Evanescent Wave Trapping

2011 ◽  
pp. 51-70
Author(s):  
Jonathan M. Taylor
Keyword(s):  
Evanescent Wave ◽  
Wave Trapping

scholarly journals Evanescent-Wave Trapping and Evaporative Cooling of an Atomic Gas at the Crossover to Two Dimensions

2003 ◽  
Vol 90 (17) ◽  
Author(s):  
M. Hammes ◽  
D. Rychtarik ◽  
B. Engeser ◽  
H.-C. Nägerl ◽  
R. Grimm
Keyword(s):  
Evanescent Wave ◽  
Evaporative Cooling ◽  
Two Dimensions ◽  
Wave Trapping ◽  
Atomic Gas

Simulation for enhancement in sensitivity of chalcogenide glasses-based fibre optic evanescent absorption sensor for malignant tissue detection

2020 ◽  
Vol 12 ◽  
Author(s):  
Ritesh Kumar Singh ◽  
Adarsh Chandra Mishra ◽  
Pooja Lohia ◽  
D.K. Dwivedi
Keyword(s):  
Evanescent Wave ◽  
Chalcogenide Glasses ◽  
Biological Tissues ◽  
Biological Species ◽  
Primary Objective ◽  
Effect Of Temperature ◽  
Refractive Indices ◽  
Core Radius ◽  
Source Illumination ◽  
Study Results

Background: Refractive index determination of biological tissues is a challenging issue. Many biological species also show vibrational signature in infrared domain. The chalcogenide-based glasses can be used to make the fiber optic evanescent wave sensors for detection of analyte. Objectives: The primary objective is to study the effect of various parameters on the sensitivity of chalcogenide glass-based evanescent wave sensor for biological tissue detection. Methods: An evanescent wave sensor has been proposed with collimated source illumination and uniform tapering. The chalcogenide materials are chosen such that the weakly guiding approximation could be followed. Complex refractive indices of liver tissue samples have been taken for the analysis of sensitivity via method of evanescent absorption coefficient. Equations for sensitivity have been solved analytically using MATLAB software. Results: The simplification of the formula for sensitivity leads to the inference that the sensitivity is a function of core radius, refractive indices of sample tissues and wavelength used. Moreover, since the refractive indices of the materials are also a function of temperature, therefore a change in temperature results into change in the profile of guiding mode. Hence the effect of temperature must also be observed. The initial simulation parameters are taken; core radius 100 µm, sensing length 4 cm and wavelength 1.0 µm. In the NIR region we have a better sensitivity of detection for all the tissues samples and the risk of photodamage of the biosamples is reduced to a good extent. It has been found that sensitivity decreases with wavelength and core radius whereas increases with temperature. It has also been shown that sensitivity is found to be better with collimated in comparison with diffused source. Conclusion: The comparative study results that one should operate at shorter NIR region of wavelength for higher sensitivity. The collimated source illumination should be preferred over diffused one for launching the light within the fiber to have high sensitivity. Further, length of sensing region should be larger but the fiber core radius should be smaller. The proposed biosensor is robust and can also be used many times if the probe (sensing region) is cleaned properly. Moreover, a small amount of analyte is enough for the detection. Thus, the proposed sensor is very useful for bio-medical applications with its high performance, accuracy and robustness.

scholarly journals Wave trapping and E × B staircases

2021 ◽  
Vol 28 (4) ◽  
pp. 042302
Author(s):  
X. Garbet ◽  
O. Panico ◽  
R. Varennes ◽  
C. Gillot ◽  
G. Dif-Pradalier ◽  
...  
Keyword(s):  
Wave Trapping

scholarly journals Unusual Polarization Relation between Single-Mode Lasing Emission and Excitation Laser from an Evanescent-Wave Pumped Micro-Cavity Laser

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 66
Author(s):  
Yuchen Wang ◽  
Hongsheng Li ◽  
Shu Hu ◽  
Heng Li ◽  
Chuanxiang Sheng
Keyword(s):  
Evanescent Wave ◽  
Single Mode ◽  
Transverse Magnetic ◽  
Ethanol Solution ◽  
Pump Laser ◽  
Fiber Axis ◽  
Lasing Threshold ◽  
Polarization Direction ◽  
Excitation Laser ◽  
Output Laser

Using a fiber of that is 125 μm in diameter in rhodamine 6G ethanol solution, controllable multi- and single-whispering-gallery-mode (WGM) optofluidic lasers based on evanescent-wave-coupled gain are both available. With multi-mode WGM emission, lasing emission with almost pure TM (transverse magnetic) or almost TE (transverse electric) modes can be obtained when the pump laser has an electric field parallel (perpendicular) to the fiber axis, i.e., the polarization direction of output laser is the same as that of the pump laser. On the other hand, when the laser emission is single-mode, the TE output laser always emerges firstly above lasing threshold, then keeps TE mode while the pump laser’s intensity increases with polarization direction perpendicular to the fiber axis; on the contrary, TE emission will dwindle relatively, while the TM emission emerges and dominates the spectra, when the pump laser’s intensity increases with polarization parallel to the fiber axis. Our work proves that controlling the leakage of the evanescent wave from high-Q microcavities is crucial for both modes of lasing emission and its polarization.

Phase-locked pair of terahertz quantum cascade lasers through evanescent-wave coupling

2020 ◽  
Vol 109 ◽  
pp. 103427
Author(s):  
Chang Gaolei ◽  
Zhu Huan ◽  
Yu Chenren ◽  
Zhu Haiqing ◽  
Xu Gangyi ◽  
...  
Keyword(s):  
Evanescent Wave ◽  
Quantum Cascade Lasers ◽  
Wave Coupling ◽  
Quantum Cascade ◽  
Cascade Lasers

scholarly journals Evolution and Vertical Structure of an Undular Bore Observed on 20 June 2015 during PECAN

2017 ◽  
Vol 145 (9) ◽  
pp. 3775-3794 ◽  
Author(s):  
Dana Mueller ◽  
Bart Geerts ◽  
Zhien Wang ◽  
Min Deng ◽  
Coltin Grasmick
Keyword(s):  
Life Cycle ◽  
University Of Wyoming ◽  
Cold Pool ◽  
Undular Bore ◽  
Wave Trapping ◽  
Hydraulic Theory ◽  
The University ◽  
Second Wave ◽  
Scorer Parameter ◽  
Equal Amplitude

This study documents the evolution of an impressive, largely undular bore triggered by an MCS-generated density current on 20 June 2015, observed as part of the Plains Elevated Convection at Night (PECAN) experiment. The University of Wyoming King Air with profiling nadir- and zenith-viewing lidars sampled the south-bound bore from the time the first bore wave emerged from the nocturnal convective cold pool and where updrafts over 10 m s−1 and turbulence in the wave’s wake were encountered, through the early dissipative stage in which the leading wave began to lose amplitude and speed. Through most of the bore’s life cycle, its second wave had a higher or equal amplitude relative to the leading wave. Striking roll clouds formed in wave crests and wave energy was detected to about 5 km AGL. The upstream environment indicates a negative Scorer parameter region due to flow reversal at midlevels, providing a wave trapping mechanism. The observed bore strength of 2.4–2.9 and speed of 15–16 m s−1 agree well with values predicted from hydraulic theory. Surface and profiling measurements collected later in the bore’s life cycle, just after sunrise, indicate a transition to a soliton.

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