Packaged Negative Axicon Optical Fiber Probe and Bessel Beam Interferometry for Refractive Index Measurement of Hazardous Liquid Samples

Pandey, Amit; Gupta, Pooja; Vairagi, Kaushal; Mondal, Samir K.

doi:10.1109/jlt.2019.2946686

Cited by 14 publications

(4 citation statements)

References 20 publications

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“…The refractive index was measured on five sites of a PDMS sheet spin-coated on a four-inch silicon substrate, as shown in Figure 5 D. In visible light region (380–780 nm), the measured data decreased slightly as the wavelength increased. Compared with that of glass coverslip (~1.52) [ 91 ], the range of refractive index (1.42–1.44) was closer to the refractive index of biological tissue (1.38–1.41) [ 92 ]. So, in the in vivo optical experiments, Ti-PDMS cranial window has less image distortion.…”

Section: Resultsmentioning

confidence: 99%

A Hybrid Titanium-Softmaterial, High-Strength, Transparent Cranial Window for Transcranial Injection and Neuroimaging

et al. 2022

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A transparent and penetrable cranial window is essential for neuroimaging, transcranial injection and comprehensive understanding of cortical functions. For these applications, cranial windows made from glass coverslip, polydimethylsiloxane (PDMS), polymethylmethacrylate, crystal and silicone hydrogel have offered remarkable convenience. However, there is a lack of high-strength, high-transparency, penetrable cranial window with clinical application potential. We engineer high-strength hybrid Titanium-PDMS (Ti-PDMS) cranial windows, which allow large transparent area for in vivo two-photon imaging, and provide a soft window for transcranial injection. Laser scanning and 3D printing techniques are used to match the hybrid cranial window to different skull morphology. A multi-cycle degassing pouring process ensures a good combination of PDMS and Ti frame. Ti-PDMS cranial windows have a high fracture strength matching human skull bone, excellent light transmittance up to 94.4%, and refractive index close to biological tissue. Ti-PDMS cranial windows show excellent bio-compatibility during 21-week implantation in mice. Dye injection shows that the PDMS window has a “self-sealing” to keep liquid from leaking out. Two-photon imaging for brain tissues could be achieved up to 450 µm in z-depth. As a novel brain-computer-interface, this Ti-PDMS device offers an alternative choice for in vivo drug delivery, optical experiments, ultrasonic treatment and electrophysiology recording.

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Section: Resultsmentioning

confidence: 99%

A Hybrid Titanium-Softmaterial, High-Strength, Transparent Cranial Window for Transcranial Injection and Neuroimaging

et al. 2022

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“…Simultaneous measurement of refractive index and thickness by rotating the sample or using a femtosecond laser [15][16][17] as a light source has also been proposed. Amit Pandey design a packaged negative axicon optical fiber probe to measure the refractive index of liquid samples under hazardous environmental condition by spectral-domain interferometry [18,19].…”

Section: Introductionmentioning

confidence: 99%

Simultaneous measurement of thickness and group refractive index in birefringent crystals

Yangmei,

Qiukun

2024

Meas. Sci. Technol.

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In order to measure the group refractive index and thickness of birefringent crystals simultaneously, a method based on spectral-domain interferometry is proposed. The optical path of each reflection layer of birefringent crystal is converted into spectral interference fringe of corresponding frequency by the principle of spectral-domain interferometry, and the accurate optical path calculation is realized by fast Fourier transform and Hanning-windowed energy centrobaric method. A two-step measurement method was designed to measure the crystal thickness and group refractive index of ordinary(o) and extraordinary(e) light synchronously by comparing the changes of the optical path before and after the insertion of the sample. The comparison between experimental and theoretical results of LiNbO3 crystals shows that the accuracy of the thickness measured by this system is better than 1μm and the relative error of the group refractive index is better than 0.15%. The measurement method is simple to implement and has high precision, which is of practical significance for realizing the rapid and high-precision measurement of optical parameters of birefringent crystals.

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“…Ideally, an optical fiber refractive index sensor must be highly sensitive and inexpensive. Tapered optical fibers have emerged as a viable solution that can provide high sensitivity [6][7][8][9][10][11][12][13]. Notably, tapered tip optical fibers are simple, easy to fabricate, cost-effective, and work with small detection volumes [6][7][8][9][10].…”

mentioning

confidence: 99%

“…Tapered optical fibers have emerged as a viable solution that can provide high sensitivity [6][7][8][9][10][11][12][13]. Notably, tapered tip optical fibers are simple, easy to fabricate, cost-effective, and work with small detection volumes [6][7][8][9][10]. These types of fibers are fabricated by etching the fiber using hydrofluoric (HF) acid to form a conical tip, which is then dipped into the liquid sample.…”

mentioning

confidence: 99%

Tapered tip optical fibers for measuring ultra-small refractive index changes with record high sensitivity

Nikbakht

Erdolu

et al. 2022

Opt. Lett.

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Here we demonstrate an inexpensive, simple, and ultra-sensitive refractive index sensor based on a tapered tip optical fiber combined with a straightforward image analysis method. The output profile of this fiber exhibits circular fringe patterns whose intensity distribution dramatically changes even with ultra-small refractive index variations in the surrounding medium. The sensitivity of the fiber sensor is measured using different concentrations of saline solutions with a transmission setup consisting of a single wavelength light source, a cuvette, an objective lens, and a camera. By analyzing the areal changes in the center of the fringe patterns for each saline solution, we obtain an unprecedented sensitivity value of 24,160 dB/RIU (refractive index unit), which is the highest value reported so far among intensity-modulated fiber refractometers. The resolution of the sensor is calculated to be 6.9 ×10−9. Moreover, we measure the sensitivity of the fiber tip in the backreflection mode using salt-water solutions and obtained a sensitivity value of 620 dB/RIU. This sensor is ultra-sensitive, simple, easy to fabricate, and low-cost, which makes it a promising tool for on-site measurements and point-of-care applications.

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Packaged Negative Axicon Optical Fiber Probe and Bessel Beam Interferometry for Refractive Index Measurement of Hazardous Liquid Samples

Cited by 14 publications

References 20 publications

A Hybrid Titanium-Softmaterial, High-Strength, Transparent Cranial Window for Transcranial Injection and Neuroimaging

A Hybrid Titanium-Softmaterial, High-Strength, Transparent Cranial Window for Transcranial Injection and Neuroimaging

Simultaneous measurement of thickness and group refractive index in birefringent crystals

Tapered tip optical fibers for measuring ultra-small refractive index changes with record high sensitivity

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