scholarly journals Using modulation acousto-optic spectrometry to locate spectral features in overlapping spectra

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
S.V. Boritko ◽  
◽  
S.I. Ivanov ◽  
A.V. Karandin ◽  
◽  
...  
Keyword(s):  
Phase Shift ◽  
Real Time ◽  
Optical Signal ◽  
Precise Determination ◽  
Spatial Modulation ◽  
Visible Range ◽  
Spectral Position ◽  
Modulation Period ◽  
Neon Lamp ◽  
Maximum Signal

The spectrometer is not able to accurately determine the spectral position of the smaller maximum if it is located against the background of a powerful broad peak. The solution of the problem is known it is enough to differentiate the existing dependence, and the position of the smaller peak is determined with sufficient accuracy. Based on a quasi-collinear acousto-optic (AO) cell, a prototype spectrometer was created, which makes it possible to record both the spectrum of the optical signal and its derivative in real time. In the course of the work, a more detailed research of the work of the created model was carried out: the value of the phase shift was changed programmatically from zero to 360°, and the spatial modulation period - from zero to the length of the AO cell L. A neon lamp and all the data presented were used as a radiation source, were obtained for the same emission line. The maximum signal for the derivative corresponds to the phase values of 90° and 270°. In another series of experiments, the work of the model was investigated with a change in the modulation period (the phase shift is fixed, ψ=π/2). The maximum signal for the derivative corresponds to the values of the modulation period duration equal to L/2, half the length of the acousto-optic cell. The graphs of the results of "physical" and "mathematical" differentiation do not coincide. We assume that the differences are related to the shape of the instrumental function of the acousto-optical spectrometer. However, at the tops of the spectral peaks, in the regions of intersection of derivatives with a zero line, the results coincide, which makes it possible to use acousto-optic differentiation to reveal the "fine structure" of optical spectra, and in real time. Thus, as a result of the work carried out: a method was proposed for the precise determination of the position of spectral maxima in complex overlapping spectra in real time; an instrumental implementation of the proposed method was created, and it was shown that for the visible range (532 nm) the accuracy of determining the spectral position of the maxima is 0.2 nm.

Acute detection of optical tissue changes in real-time during pulsed field ablation (PFA)

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
K.L Hong ◽  
O Amirana ◽  
T Ransbury ◽  
B Glover
Keyword(s):  
Real Time ◽  
Right Atrium ◽  
Optical Mapping ◽  
Energy Levels ◽  
Optical Signal ◽  
Lesion Formation ◽  
Pulsed Field ◽  
Tissue Changes ◽  
Rf Energy ◽  
The Right

Abstract Background It has been established in previous animal and human studies that it is possible to assess lesion formation in real-time using optical means during the application of radiofrequency (RF) energy in cardiac ablation procedures. The optical interrogation was accomplished using a novel catheter and instrument system whereby the catheter has embedded optical fibers that transmit and receive light from the instrument. Purpose The aim of this study was to see if there are similar indications of lesion formation, detected by the same optical means, during the application of pulsed field ablation (PFA) energy to cause lesions through electroporation. Methods A series of 3 anesthetized pigs underwent PFA in the right atrium. An 8-electrode circular catheter was placed high in the right atrium, near the superior vena cava, to simulate pulmonary vein isolation as part of an AF ablation procedure. The optical catheter was placed adjacent to the circular catheter between stimulation electrode pairs. A bolus of adenosine was administered to create a window of asystole to avoid stimulation on the T-wave. Bipolar PFA was delivered immediately post drug infusion and the optical signature from the catheter was recorded and displayed in real-time. Electrograms were recorded and the mapping of the lesion was performed with the optical catheter at the following time intervals post PFA delivery: 0 min, 15 min, 1 hour, and 3 hours. Necropsy and histology followed the procedure. Results The optical signal is distinctly higher in intensity during the PFA pulse train. The optical signal showed an immediate significant decrease and a slow but steady decay over the mapping interval. Electrogram reduction accompanied PFA application and also showed a marked reduction over the mapping interval. The optical signal amplitudes were markedly lower when on the lesion compared to healthy non-ablated myocardium as predicted. Conclusions Preliminary results indicate that optical mapping detects immediate tissue changes during PFA at these energy levels and hence could be is a viable method of evaluating lesion formation during and after PFA energy application. The optical signal indicates that cell damage occurs immediately at these energy levels and continues to progress slowly in lesions made by PFA energy compared to those made by RF energy. The findings also suggest that optical mapping can identify acute lesions made with PFA energy in real-time implying that optical mapping could evolve as a PFA gap detector. Funding Acknowledgement Type of funding source: None

scholarly journals Active Optical Signal Conditioning and Monitoring System

2021 ◽  
Author(s):  
Kalipada Chatterjee ◽  
Subrat Sahu ◽  
Venugopal Arumuru ◽  
Rajan jha
Keyword(s):  
Real Time ◽  
Signal To Noise Ratio ◽  
Optical Signal ◽  
Wide Frequency Range ◽  
Optical Systems ◽  
Signal Conditioning ◽  
Time Modulation ◽  
Response Enhancement ◽  
Signal Monitoring ◽  
External Stimuli

Abstract An optical signal conditioning technique for dynamic modulation of signals and real-time monitoring of events is pivotal for developing various optical systems at micro/nano dimensions. The utilities of such technique include controllable signal enhancement and distinctive response towards external stimuli, with reconfigurable operational range. Here, we propose and demonstrate an optical technique based on the parallel integration of fiber modal interferometers for optical response enhancement and multi-signal monitoring. Overlap of the interferometers’ characteristic spectra facilitates controllable signal filtering, attenuation, and amplification of interferometer’s response towards dynamic field over wide frequency range of 1 Hz – 1 kHz. Signal to noise ratio (SNR) enhancement of 9 dB is achieved by applying 1 volt about the reference interferometer. The system enables real-time modulation of optical signals and multipoint signal monitoring using machine learning for various applications such as mechanical vibrations, acoustic fields, biological samples, fluid movement, and other similar dynamic fields.

Design and Simulation on All Optical Real-Time Measurement of Transient Optical Signal

2016 ◽  
Vol 53 (1) ◽  
pp. 011202
Author(s):  
张卓宁 Zhang Zhuoning ◽  
彭其先 Peng Qixian ◽  
王竞 Wang Jing ◽  
温伟峰 Wen Weifeng ◽  
陶世兴 Tao Shixing
Keyword(s):  
Real Time ◽  
Optical Signal ◽  
Time Measurement ◽  
Real Time Measurement ◽  
All Optical

Real-time phase shift interference microscopy

2014 ◽  
Vol 39 (17) ◽  
pp. 5220 ◽  
Author(s):  
Avner Safrani ◽  
Ibrahim Abdulhalim
Keyword(s):  
Phase Shift ◽  
Real Time ◽  
Interference Microscopy

Precise Determination of Percent Cure of Epoxide Polymers and Composites via Fiber-Optic Raman Spectroscopy and Multivariate Analysis

1997 ◽  
Vol 51 (2) ◽  
pp. 247-252 ◽  
Author(s):  
Jeffrey F. Aust ◽  
Karl S. Booksh ◽  
Christopher M. Stellman ◽  
Richard S. Parnas ◽  
Michael L. Myrick
Keyword(s):  
Raman Spectroscopy ◽  
Multivariate Analysis ◽  
Real Time ◽  
Fiber Optic ◽  
Precise Determination ◽  
Probe Design ◽  
Epoxide Polymers ◽  
Time Determination

A method for real-time determination of the percent cure of epoxies via in situ fiber-optic Raman spectroscopy has been developed. This method utilizes a probe design developed for real-time monitoring of polymer curing and multivariate analysis to interpret the data and determine percent cure. This method was demonstrated to be reliable to ±0.54% of cure in laboratory samples over a 50–99% cure range. A preliminary study measuring cure percentage in an industrial, glass-reinforced composite has been shown to be reliable to ±0.82% in the 40–90% cure range.

Effect of Phase Shift Deviation on the Performance of an Optical 90o Hybrid without Cross-over

2011 ◽  
Vol 403-408 ◽  
pp. 1813-1816
Author(s):  
Wei Hua Liu ◽  
Cheng Zhi Xu ◽  
Yuan Zhong Xu
Keyword(s):  
Phase Shift ◽  
Phase Shifter ◽  
Signal To Noise Ratio ◽  
Optical Signal ◽  
Signal To Noise ◽  
Power Inputs ◽  
Phase Deviation ◽  
Noise Ratio ◽  
Dc Component

The effect of the phase deviation on the phase shifter in a 2 × 4 optical 90 hybrid without cross-over is discussed based on a set of formulas derived for the output of this structure. We found that if the two power inputs are equal, the phase deviation of the phase shifter only introduces attenuation in output AC component, and if not equal, it not only introduces the AC component attenuation, but also leads to DC component differentiation, which degrades the optical signal-to-noise ratio of the quadrature output.

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