Optical fiber optrodes are attractive sensing devices due to their ability to perform point measurement in remote locations. Mostly, they are oriented to biochemical sensing, quite often supported by fluorescent and s...Optical fiber optrodes are attractive sensing devices due to their ability to perform point measurement in remote locations. Mostly, they are oriented to biochemical sensing, quite often supported by fluorescent and spectroscopic techniques, but with the refractometric approach considered as well when the objective is of high measurement performance, particularly when the focus is on enhancing the measurand resolution. In this work, we address this subject, proposing and analyzing the characteristics of a fiber optic optrode relying on plasmonic interaction. A linearly tapered optical fiber tip is covered by a double overlay： the inner one - a silver thin film and over it - a dielectric layer, with this combination allowing to achieve, at a specific wavelength range, surface plasmonic resonance （SPR） interaction sensitive Typically, the interrogation of the SPR sensing to the refractive index of the surrounding medium. structures is performed, considering spectroscopic techniques, but in principle, a far better performance can be obtained, considering the reading of the phase of the light at a specific wavelength located within the spectral plasmonic resonance. This is the approach which is studied here in the context of the proposed optical fiber optrode configuration. The analysis performed shows the combination of a silver inner layer with a dielectric titanium oxide layer with tuned thicknesses enables sensitive phase reading and allows the operation of the fiber optic optrode sensor in the third telecommunication wavelength window.展开更多
An implantable optrode with micro-thermal detectors was designed to investigate the availability and safety of INS using high repetition rates.Optical auditory brainstem responses(oABRs)were recorded in normal-hearing...An implantable optrode with micro-thermal detectors was designed to investigate the availability and safety of INS using high repetition rates.Optical auditory brainstem responses(oABRs)were recorded in normal-hearing guinea pigs,and the energy thresholds,pulse durations,and ampli-tudes evoked by the varied stimulus repetitions were analyzed.Stable oABRs could be evoked through INS even as the repetition rate of stimulation reached 19 kHz.The energy threshold of oABRs was elevated,the amplitudes decreased as pulse durations increased and repetition rates were higher,and the latencies were delayed as the pulse durations increased.The temperature variation curves on the site of stimulation significantly increased as the pulse duration increased to 400μs.INS elevated the temperature around the stimulus site area via thermal accumulation during radiation,especially when higher repetition stimuli were used.Our results demonstrate that high repetition infrared stimulations can safely evoke stable and available oABRs in normal-hearing guinea pigs.展开更多
文摘Optical fiber optrodes are attractive sensing devices due to their ability to perform point measurement in remote locations. Mostly, they are oriented to biochemical sensing, quite often supported by fluorescent and spectroscopic techniques, but with the refractometric approach considered as well when the objective is of high measurement performance, particularly when the focus is on enhancing the measurand resolution. In this work, we address this subject, proposing and analyzing the characteristics of a fiber optic optrode relying on plasmonic interaction. A linearly tapered optical fiber tip is covered by a double overlay： the inner one - a silver thin film and over it - a dielectric layer, with this combination allowing to achieve, at a specific wavelength range, surface plasmonic resonance （SPR） interaction sensitive Typically, the interrogation of the SPR sensing to the refractive index of the surrounding medium. structures is performed, considering spectroscopic techniques, but in principle, a far better performance can be obtained, considering the reading of the phase of the light at a specific wavelength located within the spectral plasmonic resonance. This is the approach which is studied here in the context of the proposed optical fiber optrode configuration. The analysis performed shows the combination of a silver inner layer with a dielectric titanium oxide layer with tuned thicknesses enables sensitive phase reading and allows the operation of the fiber optic optrode sensor in the third telecommunication wavelength window.
基金This work was supported by grants from the National Natural Science Foundation of China(81660173)the Natural Science Foundation of Jiangxi Province(20202BABL206065)the Key Research and Development Program of Jiangxi Province(20181BBG78013).
文摘An implantable optrode with micro-thermal detectors was designed to investigate the availability and safety of INS using high repetition rates.Optical auditory brainstem responses(oABRs)were recorded in normal-hearing guinea pigs,and the energy thresholds,pulse durations,and ampli-tudes evoked by the varied stimulus repetitions were analyzed.Stable oABRs could be evoked through INS even as the repetition rate of stimulation reached 19 kHz.The energy threshold of oABRs was elevated,the amplitudes decreased as pulse durations increased and repetition rates were higher,and the latencies were delayed as the pulse durations increased.The temperature variation curves on the site of stimulation significantly increased as the pulse duration increased to 400μs.INS elevated the temperature around the stimulus site area via thermal accumulation during radiation,especially when higher repetition stimuli were used.Our results demonstrate that high repetition infrared stimulations can safely evoke stable and available oABRs in normal-hearing guinea pigs.
