Radiation-induced attenuation self-compensating effect in super-fluorescent fiber source

The compact super-fluorescent fiber source （SFS） output spectra variations at different pump currents and under different dose of gamma-ray radiation were measured and compared respectively. The radiation-induced attenuation （RIA） self-compensating effect in SFS based on photo-bleaching was found and the general mathematic model of SFS output spectra variations was made. The radiation-induced background attenuation （RIBA） at the pump wavelength was identified to be the main cause of the total output power and spectra variations and the variations can then be compensated by active control of the pump power to enhance the self-compensating effect. With closed-loop feedback control of pump current, double-pass backward （DPB） configuration and spectrum re-shaping technology, an SFS prototype was made and tested. The mean-wavelength stability of about 87.4 ppm and output power instability of less than 5% were achieved under up to 200 krad （Si） gamma-ray irradiation.

Underwater Optical Fiber Fluorescent System for Measuring Chlorophyll-a Concentration

Using optical fiber fluorescent technology,a new method for measuring alga concentration in water is presented. The system can realize on line measurement for alga concentration using He Ne laser as the light source. It can also effectively detect weak signals. The system with a passive sensor head has such advantages as simple structure, high sensitivity and high accuracy. It has been demonstrated that this system can be used to monitor water quality and can also be used to survey some matter.

All Fiber-optic Fluorescent Spectral Measurement and Analysis on Alga Chla/c Characteristics

The fluorescent principle used for measuring alga characteristic parameters and the optimum structure design of the instrument are discussed. The fluorescent spectrum of Chla/c and the time-resolved different spectrum ΔA(λ,t) are given. The research provides an effective method for considering the density and the classification of algae, which will be helpful to monitor sea pollution.

Optical Fiber Lightening for Fluorescence Signal Detection with Thermal Stability in Dentistry

Dental caries diagnosis system has been made with a fiber lighting, camera module and band pass filter. By simply aligning a 405 nm LED (Light Emitting diode) chips directly connected polymer fibers, a compact lighting for dental fluorescence imaging could be implemented. Special designed fiber holder with proper hole diameter was fabricated to directly connect polymer fibers with 1 mm fiber diameter and increased coupling efficiency between fibers and LEDs. Fibers connected to fiber holder were polished by polishing machine to reduce insertion loss of the fiber. Experimentally, an optical insertion loss of the fiber bundle of up to 0.8 dB was achieved. Further, LED array module was packaged with equally spaced LED chips with fiber holder on metal. Fiber lightening was fabricated with directly coupled between LED array module and fiber bundle by UV epoxy without focusing lens in order to lower the lightening temperature of intraoral camera in the human mouth. The measured temperature of fabricated fiber lightening was about 25 degree celcius. To achieve a fluorescence image and dental caries diagnosis, the proper optical filter, camera module, 405 nm fiber bundle lighting and software were investigated. The performance of the fluorescence intraoral camera with fiber lightening is confirmed by fluorescence image of human tooth.

A Fluorescence Optical Fiber Sensor for Amrinon Using a New Oxazole Compound

A new oxazole compound, 1,4 bis(naphtho[1,2 d][1,3]oxazol 2 yl)benzene(BNOB) was synthesized and incorporated into a thin plasticized polymeric membrane for sensing Amrinon. The sensor exhibits a linear response to Amrinon in the range of 7 98×10 -7 —1 52×10 -4 mol/L at pH 3 28—4 04. The response mainly originates from the Primary Inner Filter Effect, which causes a decrease in the fluorescence intensity of the sensor membrane. The distinct advantages of the proposed sensor are of full reversibility, high sensitivity and selectivity as well as short response time(<1 min), indicating that the sensor can be used to monitor Amrinon in serum samples.

Optical Fiber Thermometer Based on the Fluorescence Life time

Anew opticalfiberfluorometricthermometerbased onthetemperature dependence ofthefluorescencelifetime of phosphoris described. The phase-locked detection (PLD) system is used to measure fluorescencelifetime. The characteristics ofthermometerare discussed and the experimentresults are given.

Fiber-fluorescence in situ hybridization analyses as a diagnostic application for orientation of microduplications

Microduplications are normally invisible under microscopy and were not recognized before chromosomal microarray testing was available. Although it is difficult to confirm the orientation of duplicated segments by standard fluorescence in situ hybridization(FISH), our data indicates that fiber-FISH analysis has the potential to reveal the orientation of duplicated and triplicated segments of chromosomes. Recurrent microduplications reciprocal to microdeletions show tandem orientations of the duplicated segments, which is consistent with a non-allelic homologous recombination mechanism. Several random duplications showed tandem configurations and inverted duplications are rare. Further analysis is required to fully elucidate the basic mechanisms underlying such duplications/triplications.

Manipulable multipurpose nanothermometers based on a fluorescent hybrid glass fiber microsphere cavity

Fluorescent nanothermometers for remote temperature measurement at the micro/nanoscale have stimulated growing efforts in developing efficient temperature-responsive materials and detection procedures.However,the efficient collection and transmission of optical signals have been a tremendous challenge for practical applications of these nanothermometers.Herein,we design an all-fiberized thermometry based on a fiber-coupled microsphere cavity coated with thermo-sensitive NaYF_(4)∶20%Yb^(3+);2%Er^(3+)@NaYF_(4)nanocrystals(NCs),allowing for spatial temperature sensing with resolution down to the few-micrometer scale.In our design,the microsphere efficiently excites the NCs and collects their upconversion emissions,and the use of a fiber splitter coupled with the microsphere allows for lossless routing of excitation and emitted light.We demonstrate the use of this all-fiber temperature sensor in diverse environments,especially in strongly acidic and alkaline conditions.Leveraging the high flexibility of commercial silica fiber,this all-fiber temperature ensor was employed for stable fixed-point real-time temperature measurement and multipurpose temperature recording/mapping in opaque environments,microscale areas,various solutions,and complicated bent structures.Thus,the demonstrated design could have strong implications for the practical use of nanothermometers in various possible scenarios,especially monitoring temperatures in diverse physiological settings.

Preparation and Detection of Extended DNA Fibers of Chinese Cabbage

Abstract [Objective] The paper was to prepare and detect the extended DNA fibers of Chinese cabbage. [Method] Chinese cabbage nuclei was first successfully isolated by chopping young leaves with a blade, then nuclei were lysed by SDS to release DNA, and DNA fibers were dragged and extended with a coverslip. [Result] The results of Fiber-FISH with genomic DNA and 25S rDNA as probes showed that DNA fiber size as long as about 1.93 Mb could be measured and the number of 25S rDNA copies region were estimated to be 258 and 687 in Chinese cabbage genome. DNA fibers prepared by this method showed equally spread parallel thread with clear background, and were suitable for FISH analysis. [Conclusion] The study would accelerate Chinese cabbage genome mapping and organization analysis.

Rare Earth Doped Optical Fibers for Temperature Sensing Utilizing Ratio-Based Technology

A new and practical fluorescence temperature detecting system based on fluorescence intensity ratio was proposed . The background theory of fluorescence intensity-ratio method was presented simply. And the characters of rare earth doped samples were detailed. The erbium-doped fiber was chosen as the sensing element. The energy levels of 2H11/2 and 4S3/2 are responsible for the emission of radiation at approximately 530 and 555 nm. The erbium-doped (960 ppm) fiber of length 20 cm and core diameter 3.2μm was used as the sensing part. A silica photodiode transfers the fluorescence signal to electric signal, then the ratio of the average of the two different signals was calculated by the computer and the temperature was obtained. The ratio R of the intensity resulting from the transition between the two levels varies proportionly with temperature interval from 293 K to 373 K. The sensitivity of the sensor is approximately 0.05 K-1.

Determination of total selenium in geological samples by HG-AFS after concentration with thiol cotton fiber

Standard reference material and different geological samples were dissolved by system A (the mixture of nitric and perchloric acids) and system B (mixture of nitric, perchloric and hydrofluoric acids), and total Se in all samples was measured by hydride-generation atomic fluorescence spectrometry (HG-AFS) after concentration with thiol cotton fiber (TCF). The analytical results obtained by the two digestion method are in good agreement (within the limit of errors) for most of the samples, particularly for those having recommended values. The Se concentrations determined by the two methods are of no difference, and the correlation coefficient is 0.9986; the relative standard deviation (RSD) for the determination of 0.04 μg/g Se is 10.2%. The recovery rates of systems A and B by the stan- dard-addition method were 96%–106% and 99%–104%, respectively.

Preparation and Properties of Sensing Membrane for Fiber Optic Oxygen Sensor

Four sensing membranes based on fluorescence quenching were prepared by sol-gel method and CA membrane method, and the Ru(Ⅱ) complexes, Ru( bpy)3 Cl2 and Ru(phen)3 Cl2 , were used as the indicators . The results indicate that the volume fraction of oxygen o2 have a linear relationship in large scale with tan0/tanfor all of the sensing membranes. They have super properties such as excellent limit of detection ,fast response time and good reproducibility. The stability of the sensing membranes made by sol-gel method is better than those by CA membranes, but the uniformity of the latter is better than that of the former.

Smartphone microendoscopy for high resolution fluorescence imaging

High resolution optical endoscopes are increasingly used in diagnosis of various medical condi-tions of internal organs,such as the cervix and gastrointestinal(GI)tracts,but they are too expensive for use in resource poor settings.On the other hand,smartphones with high resolution cameras and Internet access have become more affordable,enabling them to difuse into most rural areas and developing countries in the past decade.In this paper,we describe a smartphone microendoscope that can take fuorescence images with a spatial resolution of 3.1 pum.Images collected from ex vivo,in vnitro and in vivo samples using the device are also presented.The compact and cost-effective smart phone microendosoope may be envisaged as a powerful tool for detecting pre cancerous lesions of internal organs in low and middle income countries(LMICs).

Novel Portable Oil Ingredient Instrument with Optical Fiber Link

The operation principle of a novel portable oil ingredient instrument is introduced. Using the theory of fluorescence measurement, this instrument can carry out fast and consecutive in-situ detection of oil ingredient in sea water, confirming fast and correctly the situation of oil contamination such as the concentration and the area, etc. The lowest detectable concentration for the instrument is 1×10 -8 g/ml with the precision of less than 3 %. The results of experiment and practice show that this system has well water-sealed characteristic and repeatability.

Novel Fiber Optic Fluorometer for the Measurement of Alga Concentration

A novel fluorometer based on fiber optics is briefly introduced for the measurement of alga concentration. Both the exciting light and the fluorescence from alga chlorophyll are transmitted along a fiber cable. By this way, we can get alga concentration by measuring its chlorophyll a fluorescence intensity. The experiment results show that this instrument is characterized by good sensitivity, linearity and accuracy.

An HC-PCF Fluorescence Spectrocopy for Detection of Microsphere Samples Based on Refractive Index Scaling Law

This paper illustrates an efficient fluorescence detection of micro particles using hollow-core photonic crystal fibers (HC-PCFs) by applying the refractive index (RI) scaling law. The variations in the central wavelength for different filling material indices are illustrated for most commonly available HC-PCFs that have cladding made of pure fused silica with array of air holes running along the entire length of the fiber. The proposed concept is verified by immobilizing fluorescent microsphere samples inside two HC-PCFs of different central wavelengths and the quantification of fluorescence inside the fibers is performed through spectroscopic analysis. The sensitivity has been compared for similar fiber with different dispersed media and different fibers with same dispersed medium.

All-fiber Based Er^(3+)∶Yb^(3+) Co-doped Fiber Laser

An all-fiber based Er~ 3+ ∶Yb~ 3+ co-doped double clad fiber laser operating at 1550nm is demonstrated. By using 9m long Er~ 3+ ∶Yb~ 3+ co-doped fiber(EYDF) as the gain medium, and using a pair of fiber Bragg gratings as wavelength filters, the line-width of the output laser is as narrow as 0.2nm and the output power is more than 6mW. The fluorescent effect of the laser before its emission is also studied. And it is found that the Er~ 3+ ∶Yb~ 3+ co-doped double-clad fiber laser also exhibits a high gain for Yb~ 3+ transition near 1080nm.

A Fiber Optic Sensor for 2-cholrophenol Analysis based on Oxygen Sensing System

A fiber optic 2-cholrophenol（2-CP） sensor was developed based on the fluorescence quenching of molecular oxygen on the oxygen-sensitive membrane and O2 consumption during catalytic oxidation reaction of 2-CP. The 2-CP concentration can be determined by utilizing a lock-in amplifier to measure the change in the fluorescence lifetime of an oxygen-sensitive membrane, in which the tris（2,2′-bipyridyl） ruthenium（II） chloride complexes（Ru（II）（byp）3Cl2） were immobilized in cellulose acetate（CA） via simple hybridized approach. The experimental results show the good linear relationship between the phase delay of sensitive membrane and 2-CP concentration in its detection range of 1×10-7 to 1×10-5 mol/L and 1×10-5 to 1×10-4 mol/L. The detection limit of the sensor is 7×10-8 mol/L（S/N=3） and the response time is 5 min. Our experimental measurements confirmed good response characteristics of the as-prepared fiber optic 2-CP sensor, as well as its capability to detect the 2-CP concentration in practical water samples.

An Optical Fiber Sensor for Simultaneous Measurement of pO2 and pH

Whether in the monitoring of critically ill patients such as shock, respiratory failure, brain injury, or in major anesthesia surgeries, it is necessary to evaluate the patient’s pO2 and pH. An optical fiber sensor presented is capable of monitoring the presence of oxygen partial pressure (pO2) and pH in the real-time. The sensor is based on fluorescence sensing of polymer immobilized in the oxygen/pH-sensitive membranes and covalently attached to the optical fiber probe. The design of this sensor uses LED as light source, which is an excitation light source, inducing specific wavelengths of fluorescence on the oxygen/pH-sensitive membrane. The intensity and lifetime of fluorescence are related to the pO2 and pH. So the pO2 and pH can be measured by the relationship between the pO2/pH values and the intensity and lifetime of fluorescence. The signal conditioning system based on DSP and STM32 was used to store and process data, and display test values. The response of the sensor for pO2 and pH monitoring with nitrogen (N2) as a balancing gas in the laboratory was performed. Finally, the oxygen/pH sensing scheme presented in this work is intended for using in biological, medical and environmental applications.