다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

A topical review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime. Results from numerical simulations are used to discuss the temporal and spectral characteristics of the supercontinuum, and to interpret the physics of the underlying spectral broadening processes. Particular attention is given to the case of supercontinuum generation seeded by femtosecond pulses in the anomalous group velocity dispersion regime of photonic crystal fiber, where the processes of soliton fission, stimulated Raman scattering, and dispersive wave generation are reviewed in detail. The corresponding intensity and phase stability properties of the supercontinuum spectra generated under different conditions are also discussed.

Supercontinuum generation, photonic crystal fiber

The direct exposure of volatile organic compounds (VOCs) is widely related to several adverse health effects. Therefore, an accurate amount of its usage is necessary required depending on the threshold limit. There have been a variety of sensors developed to measure an amount of VOC for safety use. Optical fiber-based VOC sensors offer huge advancements in technologies to overcome several limitations from the convectional VOC sensors that appeared over the past decade. Real-time monitoring and detection of VOCs are important to maintain a safe and healthy domestic/industrial environment. The optical fibers are highly-sensitive and widely applied to several ranges of parameters including gas sensing, and have also been used to monitor VOCs at the sub-ppm range. Recognizing the major developments in the field of the optical fiber, this article aims to review the recent progress in VOC monitoring, resulting in a wide range of sensing configurations are being discussed. Additionally, the article highlights the advantages, limitations, and future possibilities in this area. 

A review on all-optical fiber-based VOC sensors: Heading towards the development of promising technology

An all-normal dispersion supercontinuum generation in the range of 950 ÷ 1100 nm in photonic crystal fiber with core infiltrated with toluene is reported. The regular lattice hollow core photonic crystal fiber with a large core of 12 μm was designed and developed. The photonic crystal fiber core was selectively filled with toluene. The investigated fiber has normal dispersion in the wavelength range of 0.5 ÷ 2μm, while the absolute value of dispersion varies from 150 to 5 ps/nm/km in the range of 1 ÷ 2µm wavelength. The fiber nonlinear coefficient is 130 W−1km−1 as a result of the trade-off of high nonlinearity of toluene and a large mode area of the fundamental mode. The large mode area is required for the efficient delivery of high power pulses from large mode area input fiber in an all fiber system. As a pump source, a standard subpicosecond fiber laser emitting at 1030 nm with 10nJ pulse energy was used.

All-normal dispersion supercontinuum generation in photonic crystal fibers with large hollow cores infiltrated with toluene

Laser-based gas sensors utilizing various light-gas interaction phenomena have proved their capacity for detecting different gases. However, achieving reasonable sensitivity, especially in the mid-infrared, is crucial. Improving sensor detectivity usually requires incorporating multipass cells, which increase the light-gas interaction path length at a cost of reduced stability. An unconventional solution comes with the aid of hollow-core fibers. In such a fiber, light is guided inside an air-core which, when filled with the analyte gas can serve as a low-volume and robust absorption cell. Here we report on the use of a borosilicate antiresonant hollow-core fiber for laser-based gas sensing. Due to its unique structure and guidance, this fiber provides low-loss, single-mode transmission $ {\gt} {5}\;{\unicode{x00B5}{\rm m}}$>5µm. The feasibility of using the fiber as a gas cell was verified by detecting nitrous oxide at 5.26 µm with a minimum detection limit of 20 ppbv.

/pdf/nitrous-oxide-detection-at-5-26-um-with-a-compound-glass-4spqd9u3t6.pdf

Nitrous oxide detection at 5.26 µm with a compound glass antiresonant hollow-core optical fiber.

Interactions between light and various cells in cultures, such as bacteria or mammalian cells, are widely applied for optical sensors and optofluidic systems. These microorganisms need to be kept in proper aqueous media, referred to as buffers or cell culture media, that are required, respectively, for stable storage or delivering biochemical nutrients for their growth. When experiments or numerical analyses on optical devices are performed, the properties of these media are usually considered to be similar to those of pure water, with negligible influence of biochemical compounds on the medium’s optical properties. In this work, we investigated the transmission, material dispersion, and scattering properties of selected and widely used buffers and cell culture media. We show that the optical properties of these media may significantly vary from those of water. Well-defined properties of buffers and cell culture media are essential for proper design of various optical sensing or future optofluidic systems dealing with biological structures.

https://www.mdpi.com/2076-3417/9/6/1145/pdf

Optical Properties of Buffers and Cell Culture Media for Optofluidic and Sensing Applications

A photonic crystal fibre with hollow core filled with toluene is considered as a new system for coherent supercontinuum generation. The dispersion characteristics are studied for various geometrical parameters of photonic crystal fibres. Two structures with lattice constant 2 μm, filling factors d/Λ 0.3 and 0.35 and toluene core of diameters of 3.34 and 3.23 μm have flat dispersion in the near infrared range. The structure with d/Λ = 0.3 has all-normal dispersion characteristics in whole near-infrared wavelength range, while the second structure (d/Λ = 0.35) has anomalous dispersion for wavelengths longer than 1.5 μm. Although confinement losses in the considered structures are as high as 0.4 dB cm−1, we show that the generation of coherent supercontinuum in the range 1.0–1.7 μm with the pulse energy conversion of 16% is feasible in 4 cm long fibre samples with standard fibre femtosecond lasers.

Supercontinuum generation in photonic crystal fibres with core filled with toluene

All-normal dispersion supercontinuum generation (SG) in a large hollow core photonic crystal fiber (PCF) infiltrated with carbon tetrachloride is studied experimentally. The PCF is optimized to have a flat normal dispersion in a broadband range (0.8–1.7 µm) varying from -150 to 0 ps/nm/km. The effective mode area at pump wavelength (λ=1030 nm) is as large as 42.2 µm2 and readily meets the requirements for an all-fiber supercontinuum system. Infiltration of the core with carbon tetrachloride ensures a high nonlinear coefficient of the fiber equal to 22 1/W/km. Using an off-the-shelf 1030 nm fiber laser with 400 fs and 25 nJ input pulses, we generated an all-normal supercontinuum in the 850–1250 nm wavelength range.

Supercontinuum generation in an all-normal dispersion large core photonic crystal fiber infiltrated with carbon tetrachloride

https://iopscience.iop.org/article/10.1088/1555-6611/ab6f09/pdf

Khoa Dinh Xuan

Papers

Optical Properties of Buffers and Cell Culture Media for Optofluidic and Sensing Applications

All-normal dispersion supercontinuum generation in photonic crystal fibers with large hollow cores infiltrated with toluene

Supercontinuum generation in photonic crystal fibres with core filled with toluene

Supercontinuum generation in an all-normal dispersion large core photonic crystal fiber infiltrated with carbon tetrachloride

Supercontinuum generation in photonic crystal fibers infiltrated with nitrobenzene