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Michael J. Serpe - One of the best experts on this subject based on the ideXlab platform.
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probing the response of poly n isopropylacrylamide microgels to solutions of various salts using Etalons
Journal of Colloid and Interface Science, 2021Co-Authors: Wildemar S P Carvalho, Yingnan Zhang, Cayo Lee, Adam Czarnecki, Michael J. SerpeAbstract:The Hofmeister series is a qualitative ordering of ions according to their ability to precipitate proteins in aqueous solution and is extremely important to consider when trying to understand materials and biomolecular structure and function. Herein, we utilized optical devices (Etalons) composed of poly(N-isopropylacrylamide) (pNIPAm)-co-10% acrylic acid (AAc) or pNIPAm-based microgels to investigate how various salts in the Hofmeister series influenced the microgel hydration state. Etalons were exposed to a series of salts solutions at different concentrations and the position of the peaks in the reflectance spectra monitored using reflectance spectroscopy. As expected, pNIPAm-co-10%AAc microgel-based Etalons responded to the presence of ions, although in this case the response to cations deviated from the Hofmeister series. However, when using Etalons prepared with pNIPAm-based microgels, the responses followed the Hofmeister series for both cation and anions. Finally, we observed that the sensitivity of Etalons prepared with pNIPAm microgels was significantly higher than the response obtained from Etalons composed of pNIPAm-co-10%AAc microgels. This was explained by considering the charge on the pNIPAm-co-10%AAc microgels that influences how osmotic and Hofmeister effects impacts hydration state.
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volatile organic compound vapor detection with responsive microgel based Etalons
Sensors and Actuators B-chemical, 2019Co-Authors: Yingnan Zhang, Wildemar S P Carvalho, Changhao Fang, Michael J. SerpeAbstract:Abstract Optical sensors (Etalons) composed of poly(N-isopropylacrylamide) (pNIPAm)-based microgels have been developed for detecting volatile organic compound (VOC) vapors such as hexane, cyclohexane, chloroform, petroleum ether and tetrahydrofuran (THF). PNIPAm-based microgels were synthesizedandcharacterized, and Etalons were subsequently fabricated, which exhibited visual color and multipeak reflectance spectra. The color change of Etalons in response to VOC vapor exposure was evaluated by bubbling the vapors through water containing the etalon, and the shift in the reflectance peak position monitored. The results showed that the Etalons were able to respond to the VOC vapor by changing their color, as evidenced by a shift in the position of the reflectance peak. Dynamic light scattering data showed that the microgels dissolved in solutions composed of the respective VOCs exhibit sizes that vary with VOC type and concentration, which leads to the optical response observed for the microgel-based Etalons. The results showed that the Etalons were most responsive to THF, which we conclude is a result of cononsolvency of the microgels in THF/water mixtures. With the setup used here, we could detect 1.27 mM THF vapor in 4 min, although the limit of detection, and detection time, can be tuned by changing the experimental conditions. Finally, we showed that individual Etalons can be used at least 3 times to detect THF vapor without a loss in etalon function, which suggests that the Etalons can be used multiple times for detecting VOC vapors.
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Poly(N-isopropylacrylamide) microgel-based Etalons for the label-free quantitation of estradiol-17β in aqueous solutions and milk samples
Analytical and Bioanalytical Chemistry, 2018Co-Authors: Yaxin Jiang, Marcos G. Colazo, Michael J. SerpeAbstract:A novel estradiol-17β (E2) biosensor was constructed from poly( N -isopropylacrylamide) (pNIPAm) microgel-based Etalons by modification of their outermost Au layer with an E2 binding 75-mer DNA aptamer. When E2 is not present in the solution, the aptamer forms a loose/linear structure that allows ions to pass through and into the microgel layer. The ions can change the solvation state of the microgels, which changes the optical properties of the etalon. When E2 is present in the solution, the aptamer binds the E2 and undergoes a conformational change to a form that can block the diffusion of salt ions into the microgel layer. This blocking decreases the response of the device to salt exposure, which can be related to the concentration of E2 in solution. Using this approach, E2 sensor showed a dynamic range of 0.9–200 pg/mL with a calculated detection limit of 0.9 pg/mL (3.2 pM) E2, and the lowest measured concentration of E2 is 5.0 pg/mL. This sensor also showed low cross reactivity with progesterone, a similar steroid hormone. Moreover, this sensor could be regenerated five times without losing its sensitivity. Finally, we demonstrated that the sensor could also be used to quantify E2 in commercial skim and 2% milk, as well as farm milk directly without any pre-treatment. The successful quantitation of E2 in unprocessed milk demonstrates its potential use as a “cow-side” testing device for the dairy industry. Graphical abstract ᅟ
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silver nanoparticle loaded microgel based Etalons for h2o2 sensing
RSC Advances, 2018Co-Authors: Tong Shu, Qiming Shen, Yu Wan, Wei Zhang, Xueji Zhang, Michael J. SerpeAbstract:Silver nanoparticles (AgNPs) were generated inside the network structure of poly(N-isopropylacrylamide)-co-acrylic acid (pNIPAm-co-AAc) microgels that were sandwiched between two thin Au layers (15 nm) of an etalon. This was done by introducing Ag+ to the Etalons composed of deprotonated microgels, followed by its subsequent reduction with NaBH4. The resultant microgels were collected and then characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), verifying the loading of AgNPs with relatively uniform diameter (5–7 nm) within the microgels. Furthermore, the optical properties of the resultant Etalons and their response to H2O2 were evaluated by reflectance spectroscopy. Specifically, upon the addition of H2O2, the AgNP-loaded Etalons exhibited both a red shift in the position of the reflectance peaks and an increase in reflected wavelength intensity. We hypothesize that the dual signal response of the devices was a result of oxidative decomposition of the AgNPs, enabling the microgels to swell and for more light to be reflected (due to the loss of the light absorbing AgNPs). Finally, we showed that the AgNPs could be regenerated in the used Etalons multiple times without a loss in performance. This work provides a cost-effective means to detect H2O2, which could be modified to sense a variety of other species of physiological and environmental importance through rationally loading other functional nanomaterials.
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poly n isopropylacrylamide microgel based Etalons for determining the concentration of ethanol in gasoline
Journal of Applied Polymer Science, 2015Co-Authors: Hui Huang, Michael J. SerpeAbstract:A device composed of a poly (N-isopropylacrylamide)-based microgel layer sandwiched between two thin gold layers was used as a platform for determining the amount of ethanol in gasoline (octane number of 87). This device, also known as an etalon, has unique optical properties, which depend on the diameter of the microgels that make up the device. We show that the optical properties of the device depend on the concentration of the ethanol in gasoline samples. Specifically, as the reflectance peaks shift to higher wavelength, the visual color of the device changes from green to red up to 12% (v/v) ethanol. We show that the response was consistent from sample to sample and that the devices are reusable at least three times. We went on to show that the response did not depend on the source of the gasoline, and that the etalon's response is specific to ethanol compared to other common solvents found in gasoline. The performance of these devices make them potentially useful for detecting ethanol in gasoline at the time of gasoline purchase, to determine if the gas being purchased has been adulterated. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42106.
Yuezhu Wang - One of the best experts on this subject based on the ideXlab platform.
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Diode-end-pumped single-longitudinal-mode Er:LuAG laser with intracavity Etalons at 1.6 μm
Applied Optics, 2015Co-Authors: Jing Wu, Youlun Ju, Zhenguo Zhang, Yuezhu WangAbstract:We present a laser-diode-pumped 1.6 μm single-longitudinal-mode Er:LuAG laser. The intracavity Etalons were used as mode selectors for the single-longitudinal-mode operation. The maximum single-longitudinal-mode output power was 153 mW with the wavelength of 1650.2 nm at the pump power of 9.18 W, corresponding to a slope efficiency of 4.3%. The M2 factor was measured to be 1.07. In addition, by changing the thickness of the Etalons, a maximum single-longitudinal-mode output power of 114 mW at 1628.1 nm with a slope efficiency of 3.5% was also achieved. To our knowledge, the intracavity Etalons Er:LuAG laser operated at single-longitudinal-mode is being reported for the first time.
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high power single longitudinal mode operation of tm yag laser using fabry perot Etalons and volume bragg grating
Optics Communications, 2012Co-Authors: Fei Chen, Yuezhu WangAbstract:Abstract A diode-pumped high-power single-longitudinal-mode (SLM) Tm:YAG laser was investigated. To obtain a single-frequency 2 μm laser output, Fabry–Perot (F–P) Etalons combined with a volume Bragg grating (VBG) were used as frequency selection devices. The transmission losses of the VBG and Etalons were analyzed and the angles of F–P Etalons were optimized theoretically. Considering the gains and the insertion losses, the output wavelength of the Tm:YAG laser was estimated to be 2012.47 nm. Using this method, as much as 574 mW SLM laser was obtained experimentally, corresponding to a slope-efficiency of 18.6% and an optical-to-optical efficiency of 8.2%. The output wavelength was measured to be 2012.47 nm, which was in excellent agreement with the theoretical result. The power instability was less than 1% in 30 minutes test, and the degree of the linear polarization was over 20 dB.
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room temperature operation of single frequency tm luag laser end pumped by laser diode
Laser Physics Letters, 2009Co-Authors: Qing Wang, Zhenguo Wang, F Chen, Renlai Zhou, Yuezhu WangAbstract:In this letter we report a diode-pumped single frequency Tm:LuAG laser at room temperature. One uncoated fused silica etalon (0.1 mm) and one uncoated YAG etalon (1 mm) are employed to narrow the laser line-width. Single frequency laser is achieved by tuning the angle of the Etalons. The oscillating wavelength can be changed (from 2018 to 2030 nm) and at each wavelength, single-frequency laser is achieved. The maximum single frequency laser power is up to 148.0 mW with the central wavelength of 2026.4 nm. To our knowledge, this is the first time to obtain single-frequency Tm:LuAG laser of up to 148.0 mW with Fabry-Perot Etalons in the cavity.
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diode pumped single frequency tm yag laser at room temperature
Laser Physics Letters, 2008Co-Authors: Zhenguo Wang, Qi Wang, C W Song, Yuezhu WangAbstract:A diode-pumped single frequency Tm:YAG laser operating at 2 μm is demonstrated in this letter. The laser crystal is controlled at room temperature by using a thermoelectric cooler. Two solid uncoated fused silica Etalons are employed to narrow the laser line-width, the thicknesses of which are 0.1 mm and 1 mm, respectively. By tuning the angle of the Etalons, single frequency laser is achieved and the oscillating wavelength can be changed from 2008 nm to 2021 nm. And at each wavelength, single-frequency laser is achieved. The maximum single frequency laser power is up to 75.0 mW with the central wavelength of 2013.9 nm. To our knowledge, this is the first time to obtain single-frequency Tm:YAG laser of 75.0 mW with F-P Etalons in the cavity.
Nandita Srivastava - One of the best experts on this subject based on the ideXlab platform.
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narrow band imaging system for the multi application solar telescope at udaipur solar observatory characterization of lithium niobate Etalons
arXiv: Instrumentation and Methods for Astrophysics, 2014Co-Authors: Raja A Bayanna, Shibu K Mathew, P Venkatakrishnan, Nandita SrivastavaAbstract:Multi-application Solar Telescope is a 50 cm off-axis Gregorian telescope that has been installed at the lake site of Udaipur Solar Observatory. For quasi-simultaneous photospheric and chromospheric observations, a narrow-band imager has been developed as one of the back-end instruments for this telescope. Narrow-band imaging is achieved using two lithium niobate Fabry-Perot Etalons working in tandem as a filter. This filter can be tuned to different wavelengths by changing either voltage, tilt or temperature of the Etalons. To characterize the Etalons, a Littrow spectrograph was set up, in conjunction with a 15 cm Carl Zeiss Coud\'e solar telescope. The Etalons were calibrated for the solar spectral lines FeI 6173 {\AA}, and CaII 8542 {\AA}. In this work, we discuss the characterization of the Fabry-Perot Etalons, specifically the temperature and voltage tuning of the system for the spectral lines proposed for observations. We present the details of the calibration set-up and various tuning parameters. We also present solar images obtained using the system parameters. We also present solar images obtained using the system.
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narrow band imaging system for the multi application solar telescope at udaipur solar observatory characterization of lithium niobate Etalons
Solar Physics, 2014Co-Authors: Raja A Bayanna, Shibu K Mathew, P Venkatakrishnan, Nandita SrivastavaAbstract:The Multi-application Solar Telescope is a 50 cm off-axis Gregorian telescope that has been installed at the lake site of Udaipur Solar Observatory. For quasi-simultaneous photospheric and chromospheric observations, a narrow-band imager has been developed as one of the back-end instruments for this telescope. Narrow-band imaging is achieved using two lithium niobate Fabry–Perot Etalons working in tandem as a filter. This filter can be tuned to different wavelengths by changing either voltage, tilt, or temperature of the Etalons. To characterize the Etalons, a Littrow spectrograph was set up in conjunction with a 15 cm Carl Zeiss Coude solar telescope. The Etalons were calibrated for the solar spectral lines Fe i 6173 A, and Ca ii 8542 A. In this work, we discuss the characterization of the Fabry–Perot Etalons, specifically, the temperature and voltage tuning of the system for the spectral lines proposed for observations. We present the details of the calibration set-up and various tuning parameters. We also present solar images obtained using the system.
Raja A Bayanna - One of the best experts on this subject based on the ideXlab platform.
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narrow band imaging system for the multi application solar telescope at udaipur solar observatory characterization of lithium niobate Etalons
arXiv: Instrumentation and Methods for Astrophysics, 2014Co-Authors: Raja A Bayanna, Shibu K Mathew, P Venkatakrishnan, Nandita SrivastavaAbstract:Multi-application Solar Telescope is a 50 cm off-axis Gregorian telescope that has been installed at the lake site of Udaipur Solar Observatory. For quasi-simultaneous photospheric and chromospheric observations, a narrow-band imager has been developed as one of the back-end instruments for this telescope. Narrow-band imaging is achieved using two lithium niobate Fabry-Perot Etalons working in tandem as a filter. This filter can be tuned to different wavelengths by changing either voltage, tilt or temperature of the Etalons. To characterize the Etalons, a Littrow spectrograph was set up, in conjunction with a 15 cm Carl Zeiss Coud\'e solar telescope. The Etalons were calibrated for the solar spectral lines FeI 6173 {\AA}, and CaII 8542 {\AA}. In this work, we discuss the characterization of the Fabry-Perot Etalons, specifically the temperature and voltage tuning of the system for the spectral lines proposed for observations. We present the details of the calibration set-up and various tuning parameters. We also present solar images obtained using the system parameters. We also present solar images obtained using the system.
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narrow band imaging system for the multi application solar telescope at udaipur solar observatory characterization of lithium niobate Etalons
Solar Physics, 2014Co-Authors: Raja A Bayanna, Shibu K Mathew, P Venkatakrishnan, Nandita SrivastavaAbstract:The Multi-application Solar Telescope is a 50 cm off-axis Gregorian telescope that has been installed at the lake site of Udaipur Solar Observatory. For quasi-simultaneous photospheric and chromospheric observations, a narrow-band imager has been developed as one of the back-end instruments for this telescope. Narrow-band imaging is achieved using two lithium niobate Fabry–Perot Etalons working in tandem as a filter. This filter can be tuned to different wavelengths by changing either voltage, tilt, or temperature of the Etalons. To characterize the Etalons, a Littrow spectrograph was set up in conjunction with a 15 cm Carl Zeiss Coude solar telescope. The Etalons were calibrated for the solar spectral lines Fe i 6173 A, and Ca ii 8542 A. In this work, we discuss the characterization of the Fabry–Perot Etalons, specifically, the temperature and voltage tuning of the system for the spectral lines proposed for observations. We present the details of the calibration set-up and various tuning parameters. We also present solar images obtained using the system.
Zhenguo Wang - One of the best experts on this subject based on the ideXlab platform.
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room temperature operation of single frequency tm luag laser end pumped by laser diode
Laser Physics Letters, 2009Co-Authors: Qing Wang, Zhenguo Wang, F Chen, Renlai Zhou, Yuezhu WangAbstract:In this letter we report a diode-pumped single frequency Tm:LuAG laser at room temperature. One uncoated fused silica etalon (0.1 mm) and one uncoated YAG etalon (1 mm) are employed to narrow the laser line-width. Single frequency laser is achieved by tuning the angle of the Etalons. The oscillating wavelength can be changed (from 2018 to 2030 nm) and at each wavelength, single-frequency laser is achieved. The maximum single frequency laser power is up to 148.0 mW with the central wavelength of 2026.4 nm. To our knowledge, this is the first time to obtain single-frequency Tm:LuAG laser of up to 148.0 mW with Fabry-Perot Etalons in the cavity.
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diode pumped single frequency tm yag laser at room temperature
Laser Physics Letters, 2008Co-Authors: Zhenguo Wang, Qi Wang, C W Song, Yuezhu WangAbstract:A diode-pumped single frequency Tm:YAG laser operating at 2 μm is demonstrated in this letter. The laser crystal is controlled at room temperature by using a thermoelectric cooler. Two solid uncoated fused silica Etalons are employed to narrow the laser line-width, the thicknesses of which are 0.1 mm and 1 mm, respectively. By tuning the angle of the Etalons, single frequency laser is achieved and the oscillating wavelength can be changed from 2008 nm to 2021 nm. And at each wavelength, single-frequency laser is achieved. The maximum single frequency laser power is up to 75.0 mW with the central wavelength of 2013.9 nm. To our knowledge, this is the first time to obtain single-frequency Tm:YAG laser of 75.0 mW with F-P Etalons in the cavity.