scholarly journals Simultaneous measurement method of the physical thickness and group refractive index free from a non-measurable range

2019 ◽  
Vol 27 (17) ◽  
pp. 24682 ◽  
Author(s):  
Jungjae Park ◽  
Hiroki Mori ◽  
Jonghan Jin
Keyword(s):  
Refractive Index ◽  
Simultaneous Measurement ◽  
Measurement Method ◽  
Group Refractive Index ◽  
Physical Thickness ◽  
Measurable Range

A new measurement method to simultaneously determine group refractive index and thickness of a sample using low-coherence tandem interferometry

2019 ◽  
Vol 55 ◽  
pp. 254-259
Author(s):  
Agustinus Winarno ◽  
Satoru Takahashi ◽  
Hirokazu Matsumoto ◽  
Kiyoshi Takamasu
Keyword(s):  
Refractive Index ◽  
Measurement Method ◽  
Low Coherence ◽  
Group Refractive Index

Air etalon facilitated simultaneous measurement of group refractive index and thickness using spectral interferometry

2014 ◽  
Vol 53 (31) ◽  
pp. 7483 ◽  
Author(s):  
Ke Zhang ◽  
Li Tao ◽  
Wenkai Cheng ◽  
Jianhua Liu ◽  
Zhongping Chen
Keyword(s):  
Refractive Index ◽  
Simultaneous Measurement ◽  
Spectral Interferometry ◽  
Group Refractive Index

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

Sensors ◽  
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.

scholarly journals Hybrid Grating in Reduced-Diameter Fiber for Temperature-Calibrated High-Sensitivity Refractive Index Sensing

2019 ◽  
Vol 9 (9) ◽  
pp. 1923
Author(s):  
Biqiang Jiang ◽  
Zhen Hao ◽  
Dingyi Feng ◽  
Kaiming Zhou ◽  
Lin Zhang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Simultaneous Measurement ◽  
Surrounding Medium ◽  
High Sensitivity ◽  
Fiber Grating ◽  
Bragg Resonance ◽  
Core Mode ◽  
Promising Alternative ◽  
Sensing Applications ◽  
Highly Sensitive

We propose and experimentally demonstrate a hybrid grating, in which an excessively tilted fiber grating (Ex-TFG) and a fiber Bragg grating (FBG) were co-inscribed in a reduced-diameter fiber (RDF). The hybrid grating showed strong resonances due to coupling among core mode and a set of polarization-dependent cladding modes. This coupling showed enhanced evanescent fields by the reduced cladding size, thus allowing stronger interaction with the surrounding medium. Moreover, the FBG’s Bragg resonance confined by the thick cladding was exempt from the change of the surrounding medium’s refractive index (RI), and then the FBG can work as a temperature compensator. As a result, the Ex-TFG in RDF promised a highly sensitive RI measurement, with a sensitivity up to ~1224 nm/RIU near the RI of 1.38. Through simultaneous measurement of temperature and RI, the temperature dependence of water’s RI is then determined. Therefore, the proposed hybrid grating with a spectrum of multi-peaks embedded with a sharp Bragg resonance is a promising alternative for the simultaneous measurement of multi-parameters for many RI-based sensing applications.

General expression for the group refractive index of the ionosphere

1961 ◽  
Vol 21 (1) ◽  
pp. 65-69 ◽  
Author(s):  
Y.S.N. Murty ◽  
Khastgir S.R
Keyword(s):  
Refractive Index ◽  
General Expression ◽  
Group Refractive Index

Absolute refractive index measurement method over a broad wavelength region based on white-light interferometry

2010 ◽  
Vol 49 (5) ◽  
pp. 910 ◽  
Author(s):  
Seung Hwan Kim ◽  
Seoung Hun Lee ◽  
Jae In Lim ◽  
Kyong Hon Kim
Keyword(s):  
Refractive Index ◽  
White Light ◽  
Measurement Method ◽  
Wavelength Region ◽  
White Light Interferometry ◽  
Refractive Index Measurement ◽  
Index Measurement ◽  
Absolute Refractive Index
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