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

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.

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High-sensitivity pressure sensors based on mechanically induced long-period fiber gratings and fiber loop ring-down

Optics Communications ◽

10.1016/j.optcom.2010.05.071 ◽

2010 ◽

Vol 283 (20) ◽

pp. 3945-3948 ◽

Cited By ~ 19

Author(s):

Yajun Jiang ◽

Jianlin Zhao ◽

Dexing Yang ◽

Daqing Tang

Keyword(s):

Pressure Sensors ◽

High Sensitivity ◽

Fiber Gratings ◽

Long Period ◽

Long Period Fiber Gratings ◽

Loop Ring ◽

Fiber Loop

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Configuration of ring-down spectrometers for maximum sensitivity

Canadian Journal of Chemistry ◽

10.1139/v04-038 ◽

2004 ◽

Vol 82 (6) ◽

pp. 873-879 ◽

Cited By ~ 2

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.

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An Optical Frequency Domain Angle Measurement Method Based on Second Harmonic Generation

Sensors ◽

10.3390/s21020670 ◽

2021 ◽

Vol 21 (2) ◽

pp. 670

Author(s):

Wijayanti Dwi Astuti ◽

Hiraku Matsukuma ◽

Masaru Nakao ◽

Kuangyi Li ◽

Yuki Shimizu ◽

...

Keyword(s):

Femtosecond Laser ◽

Second Harmonic Generation ◽

Frequency Domain ◽

Harmonic Generation ◽

Measurement Method ◽

Second Harmonic ◽

Angle Measurement ◽

Laser Source ◽

Optical Frequency ◽

Measurable Range

This paper proposes a new optical angle measurement method in the optical frequency domain based on second harmonic generation with a mode-locked femtosecond laser source by making use of the unique characteristic of the high peak power and wide spectral range of the femtosecond laser pulses. To get a wide measurable range of angle measurement, a theoretical calculation for several nonlinear optical crystals is performed. As a result, LiNbO3 crystal is employed in the proposed method. In the experiment, the validity of the use of a parabolic mirror is also demonstrated, where the chromatic aberration of the focusing beam caused the localization of second harmonic generation in our previous research. Moreover, an experimental demonstration is also carried out for the proposed angle measurement method. The measurable range of 10,000 arc-seconds is achieved.

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Second harmonic generation correlation spectroscopy for characterizing translationally diffusing protein nanocrystals

Acta Crystallographica Section D Structural Biology ◽

10.1107/s205979831600841x ◽

2016 ◽

Vol 72 (7) ◽

pp. 849-859

Author(s):

Ximeng Y. Dow ◽

Christopher M. Dettmar ◽

Emma L. DeWalt ◽

Justin A. Newman ◽

Alexander R. Dow ◽

...

Keyword(s):

Second Harmonic Generation ◽

Harmonic Generation ◽

Unit Volume ◽

Second Harmonic ◽

Incident Beam ◽

High Sensitivity ◽

Correlation Spectroscopy ◽

Optical Process ◽

Active Nanoparticles ◽

Low Sensitivity

Second harmonic generation correlation spectroscopy (SHG-CS) is demonstrated as a new approach to protein nanocrystal characterization. A novel line-scanning approach was performed to enable autocorrelation analysis without sample damage from the intense incident beam. An analytical model for autocorrelation was developed, which includes a correction for the optical scattering forces arising when focusing intense, infrared beams. SHG-CS was applied to the analysis of BaTiO3nanoparticles ranging from 200 to ∼500 nm and of photosystem I nanocrystals. A size distribution was recovered for each sample and compared with the size histogram measured by scanning electron microscopy (SEM). Good agreement was observed between the two independent measurements. The intrinsic selectivity of the second-order nonlinear optical process provides SHG-CS with the ability to distinguish well ordered nanocrystals from conglomerates and amorphous aggregates. Combining the recovered distribution of particle diameters with the histogram of measured SHG intensities provides the inherent hyperpolarizability per unit volume of the SHG-active nanoparticles. Simulations suggest that the SHG activity per unit volume is likely to exhibit relatively low sensitivity to the subtle distortions within the lattice that contribute to resolution loss in X-ray diffraction, but high sensitivity to the presence of multi-domain crystals.

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

Optical and Quantum Electronics ◽

10.1007/s11082-021-02971-3 ◽

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

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Fiber loop ring-down magnetic field sensor using frequency-shifted interferometry and D-shaped fiber coated with magnetic fluid

IEEE Magnetics Letters ◽

10.1109/lmag.2021.3067592 ◽

2021 ◽

pp. 1-1

Author(s):

Chunfu Cheng ◽

Jiaxuan Chen ◽

Yiwen Ou ◽

Wenjia Chen ◽

Li Fang ◽

...

Keyword(s):

Magnetic Field ◽

Magnetic Fluid ◽

Magnetic Field Sensor ◽

Field Sensor ◽

Loop Ring ◽

Fiber Loop

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

Optics Express ◽

10.1364/oe.22.011244 ◽

2014 ◽

Vol 22 (9) ◽

pp. 11244 ◽

Cited By ~ 22

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

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Influence of Irrational Beliefs and Sensitivity to a Person on Future Psychology Students’ Propensity to Coercion or Nonviolence

Sibirskiy psikhologicheskiy zhurnal ◽

10.17223/17267081/81/7 ◽

2021 ◽

pp. 143-165

Author(s):

V.G. Maralov ◽

◽

V.A. Sitarov ◽

Keyword(s):

Irrational Beliefs ◽

High Sensitivity ◽

Daily Practice ◽

Psychology Students ◽

State Universities ◽

Low Level ◽

Level Of Understanding ◽

Low Sensitivity ◽

High Level ◽

Dependent Type

The relevance of the problem is due to the importance of identifying factors that determine the propensity of students to coercion or nonviolence, creating psychological and pedagogical conditions for the formation of the socionomic sphere of nonviolent competencies for future specialists at universities. The theoretical basis of the study was the position of nonviolence as a daily practice of interaction, by which we understand the ability of a person to choose from a number of possible alternatives that carry the least charge of coercion. The aim of the work was to study the influence of irrational beliefs and sensitivity to a person (interest, empathy, understanding and assistance) on the students’ tendency to coercion, manipulation, non-violence and non-interference in the processes of interaction with people. The hypothesis was tested that the tendency of students to coercion, manipulation, and noninterference will be due to expressed irrational beliefs and low level of sensitivity to a person and the tendency to non-violence will be explained by the absence of irrational beliefs and a high level of sensitivity to a person. The study involved 125 students of pedagogical and psychological faculties of the Moscow Humanitarian and Cherepovets State universities. The authors used questionnaires to identify the positions of interaction among students and sensitivity to a person, as well as a list of irrational beliefs proposed by A. Beck and A. Freeman. It is established that the tendency to both coercion and manipulation are determined by the beliefs of anti-social type and low sensitivity to the person. The tendency to manipulate the narcissistic beliefs, high interest in people and understanding them, at the same time the tendency to non-violence and non-interference are determined by beliefs of avoidant and dependent types with a low level of understanding people. And a tendency to non-interference is determined by beliefs of dependent type with unexpressed orientation on helping. The tendency to nonviolence is determined by the high sensitivity to a person and the absence of irrational beliefs of antisocial, passive-aggressive and narcissistic types. As a result, the conclusion is made about the need to form purposefully the ability to nonviolent interaction among students, which should include the work on awareness and overcoming irrational beliefs and the development of sensitivity to a person. The obtained results can be used in practical work with students on the formation of their nonviolent competencies.

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