A new sensing platform to simultaneously identify and quantify volatile C1 to C4 alkanes in multi-component gas mixtures is presented. This setup is based on an optically pumped, broadly tunable mid-infrared vertical-external-cavity surface-emitting laser (VECSEL) developed for gas detection. The lead-chalcogenide VECSEL is the key component of the presented optical sensor. The potential of the proposed sensing setup is illustrated by experimental absorption spectra obtained from various mixtures of volatile hydrocarbons and water vapor. The sensor has a sub-ppm limit of detection for each targeted alkane in a hydrocarbon gas mixture even in the presence of a high water vapor content. 相似文献
This study presents an innovative refractive index (RI) sensor that measures glucose concentration by utilizing the photonic spin Hall effect (SHE) in a resonant optical tunneling effect (ROTE) structure. The ROTE structure consists of three InP layers with the high RI and two analyte layers (with a high-low-high-low-high RI distribution), in which glucose solution samples with the low RI are injected. By subjecting the InP layers to external bias-assisted light, the photonic SHE can be flexibly manipulated, enabling the modulation of the sensing performance accordingly. It is found that the transverse shift of photonic SHE presents a large variation in response to the tiny change in glucose concentrations. By optimizing the parameters (i.e., intensity or wavelength) of bias light, the sensitivity of this sensor can reach as high as 735.7 µm RIU−1. Compared to traditional glucose sensors, this original work implements the novel photonic SHE with the superior sensing performance. Therefore, the proposed design shows promising potential for biomedical applications, such as medical diagnoses and drug discovery. 相似文献
In this paper, a photonic crystal waveguide platform on silicon-on-insulator substrate is proposed in order to realize a highly sensitive refractive index based biosensor. Following the design, the analysis of the sensor structure are made by using the three dimensional Finite Difference Time Domain method. The principle of sensing is based on the change in refractive index, which in turn changes the output spectrum of the waveguide. Results show that the sensitivity of the sensor depends mainly on the geometrical properties of the defect region of the photonic crystal structure. The phenomenon is verified for various samples having refractive index ranging from 1 (air) to 1.57 (Bovine serum albumin). Further, the structure is compared with few other conventional photonic crystal waveguide designs to analyze the sensing performance. The estimated value of sensitivity of the sensor is found to be 260 nm/RIU with a detection limit of 0.001 RIU. This high sensitivity can enhance the performance of low-concentration analytes detection. 相似文献
An optical fiber gas sensor using hollow-core photonic bandgap fiber as a gas cell is proposed to detect H2S mixed with natural gas. This sensor is advantageous for eliminating instability of light source, impact of thermal zero drift, and zero shift of photoelectric device. The gas sensing probe of configuration is using two shorter pieces of hollow-core photonic bandgap fiber (HC-PBF) with the same overall length instead of one long piece of HC-PBF to improve the system response. The experimental dates indicate that a minimum detectivity of 10 ppm for the system configuration was estimated. 相似文献
Organic distributed feedback (DFB) lasers can be useful photonic tools for biological applications where the roles of organic materials are important, because highly coherent single mode emission with broad tuning range can be obtained. However, the formulaic structures of organic lasers, and the uses of gain media as resonators themselves, are not suitable for inducing laser emission from irregular shaped gain media, such as dye‐staining cells and tissues. Here, we report a reusable photonic template comprising an exceedingly thin and discrete titanium dioxide (TiO2) layer on a one‐dimensional (1D) quartz grating to induce single mode DFB lasing from a variety of states of optical gain media. Using the same template, the external gain media of optically thick and thin casted film, liquid, and a free‐standing thick film reveal single mode lasing with reliable performance. Numerical simulations demonstrate that the 25‐nm thick TiO2 disconnected grating lines support a spatially confined DFB mode in the vertical direction, even under no index difference between superstrate and substrate. Additionally, not using the typical waveguide gain layer promises high sensitivity and detection limit in refractometric sensing. These results suggest that the photonic structure may serve as a versatile sensing platform for bioapplications. 相似文献
We demonstrate a novel sensor type, which is based on the monolithic integration of luminescent optical sensor spots together with ring‐shaped thin‐film organic photodiodes on one substrate. The organic photodiodes serve as integrated fluorescence detectors, simplifying the detection system by minimizing the number of required optical components. The proposed concept enables filter‐less discrimination between excitation light and generated fluorescence light. The functionality of the concept is demonstrated by an integrated oxygen sensor, exhibiting excellent performance. The sensor spots are excited by an assembled organic light emitting diode. The integrated optical sensor platform is suitable for the parallel detection of multiple parameters. Sensor schemes for the analytical parameters carbon dioxide, temperature and ammonia, are proposed.
In this paper we investigate, by the plane wave expansion method and an analytical model, the temperature effect on the photonic band gap fiber, and we report on a numerical demonstration of a temperature sensor based on the photonic band gap (PBG) shift in a solid core photonic crystal fiber (PCF) infiltrated with a high refractive index oil. The bandwidth and the position of the central wavelength of the band gap are the parameters of interests for our temperature sensing purpose. Simulation results were found to be in excellent agreement with the refractive index scaling law and the highest sensitivity of 3.21?nm/°C was achieved, and it will be even higher than the grating based sensors written in PCFs with similar structure. 相似文献
We demonstrate a novel multifunctional optical system that is capable of trapping, imaging, position sensing, and fluorescence detection of micrometer-sized fluorescent test particles using hollow-core photonic crystal fiber (HC-PCF). This multifunctional optical system for trapping, position sensing, and fluorescent detection is designed such that a near-IR laser light is used to create an optical trap across a liquid-filled HC-PCF, and a 473 nm laser is employed as a source for fluorescence excitation. This proposed system and the obtained results are expected to significantly enable an efficient integrated trapping platform employing HC-PCF for diagnostic biomedical applications. 相似文献
The development of technology in photonic crystal (PC) structures has seen rapid progress. Using PCs in biosensing area may
open new venues to achieve single molecule detection, and high resolution scanning. A novel PC sensor with improved performances,
in terms of size, compactness and sensitivity is presented in this paper. The sensing element consists of dielectric cylinders
with varying radius introduced along <01> and <10> directions of the crystal. The results show that the peak wavelength shifts
to the high frequency region when only six cylinders are filled with analytes. Also, the peaks show a larger shift compared
to the structure obtained using the entire PC waveguide as sensing region. The proposed sensor shows a better sensitivity
to water than other analytes, where the peak wavelength tends to shift towards the low frequency region. 相似文献
A compact and highly linear quartz-enhanced photoacoustic spectroscopy(QEPAS)sensor for the measurement of water vapor concentration in the air is demonstrated.A cost-effective quartz tuning fork(QTF)is used as the sharp transducer to convert light energy into an electrical signal based on the piezoelectric effect,thereby removing the need for a photodetector.The short optical path featured by the proposed sensing system leads to a decreased size.Furthermore,a pair of microresonators is applied in the absorbance detection module(ADM)for QTF signal enhancement.Compared with the system without microresonators,the detected QTF signal is increased to approximately 7-fold.Using this optimized QEPAS sensor with the proper modulation frequency and depth,we measure the water vapor concentration in the air at atmospheric pressure and room temperature.The experimental result shows that the sensor has a high sensitivity of 1.058parts-per-million. 相似文献
In this paper, we propose a new design principle of two-dimensional photonic crystal refractive index sensors with high transmission and sensitivity simultaneously. The proposed sensor is made of two waveguide couplers and one microcavity which is obtained by varying the radius of one air hole in the center of PC structure. The microcavity is separated from the input and output waveguides by many holes of the PC. It is shown that by injecting an analyte such as gas or a liquid into a sensing hole, and thus changing its refractive index, a shift in the resonant wavelength may occur. The transmission spectra, quality factor and sensitivity of the sensor have been analyzed numerically by the finite difference time domain (FDTD) method. The sensitivity value of the sensor has been found to be 668 nm/(RIU with minimum detection limit of 0.002 RIU), which proves the ability of the structure to produce biosensor PhC. 相似文献
In this paper, we set up a sensing model of PSMs (porous silicon microcavities) by applying the Bruggeman effective medium
approximation theory and the transfer matrix method. In addition, we explain in detail the adsorption characteristics of porous
silicon. Finally, using an experimental setup to measure the reflectivity spectrum of PSMs when the sensor is exposed to different
organic vapors, the experimental results prove that it is a feasible optical sensor for the detection of organic species.
Resolution of the PSMs sensor is high, response time and resume time is short and repetition is good.
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The photonic spin Hall effect (PSHE), characterized by two splitting beams with opposite spins, has great potential applications in nano-photonic devices, optical sensing fields, and precision metrology. We present the significant enhancement of terahertz (THz) PSHE by taking advantage of the optical Tamm state (OTS) in InSb-distributed Bragg reflector (DBR) structure. The spin shift of reflected light can be dynamically tuned by the structural parameters (e.g. the thickness) of the InSb-DBR structure as well as the temperature, and the maximum spin shift for a horizontally polarized incident beam at 1.1 THz can reach up to 11.15 mm. Moreover, we propose a THz gas sensing device based on the enhanced PSHE via the strong excitation of OTS for the InSb-DBR structure with a superior intensity sensitivity of 5.873×104 mm/RIU and good stability. This sensor exhibits two orders of magnitude improvement compared with the similar PSHE sensor based on InSb-supported THz long-range surface plasmon resonance. These findings may provide an alternative way for the enhanced PSHE and offer the opportunity for developing new optical sensing devices. 相似文献
We propose silicon nitride two-dimensional photonic crystal resonators as flexible platform to realize photonic devices based on spontaneous emission engineering of nanoemitters in the visible spectral range. The versatility of our approach is demonstrated by coupling the two dipole-like modes of a closed band gap H1 nanocavity with: (i) DNA strands marked with Cyanine 3 organic dyes, (ii) antibodies bounded to fluorescent proteins and (iii) colloidal semiconductor nanocrystals localized in the maximum of the resonant electric field. The experimental results are in good agreement with the numerical simulations, highlighting the good coupling of the nanocavities with both organic and inorganic light emitters. 相似文献
We propose a novel technique to measure the concentration of sucrose in PAm-hydrogel sucrose solution using two dimensional photonic crystal structures consists of air holes. PAm-hydrogel is an organic hydrogels, which is used as biomedical applications. The principle of measurement is based on the linear variation of photonic band gap with the change of dielectric constant of the solution infiltrated in air holes of photonic crystal structure. Plane wave expansion method is used to find the band gap and linear variation (R2 = 0.9949) of photonic band gap with respect to sucrose concentration is observed. Besides this, an excellent linear variation (R2 = 0.9949) of transmitted intensity of light with respect to sucrose concentration is also seen. Since the simulation is based on optical principle, it gives accurate results. This suggests the possible use of 2-D photonic crystal structure as a sucrose sensor. Experimental procedure for measuring the concentration of sucrose is also mentioned. 相似文献
We propose a simple one-dimensional grating coupling system that can excite multiple surface plasmon resonances for refractive index(RI)sensing with self-reference characteristics in the near-infrared band.Using theoretical analysis and the finite-difference time-domain method,the plasmonic mechanism of the structure is discussed in detail.The results show that the excited resonances are independent of each other and have different fields of action.The mode involving extensive interaction with the analyte environment achieves a high sensitivity of 1236 nm/RIU,and the figure of merit(FOM)can reach 145 RIU-1.Importantly,the mode that is insensitive to the analyte environment exhibits good self-reference characteristics.Moreover,we discuss the case of exchanging the substrate material with the analyte environment.Promising simulation results show that this RI sensor can be widely deployed in unstable and complicated environments. 相似文献