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Timeline of Zeeshan Ahmed

2018
Oct
24
Published new article




Article

Fabrication and Testing of Photonic Thermometers

Published: 24 October 2018 by MyJove Corporation in Journal of Visualized Experiments

doi: 10.3791/55807

In recent years, a push for developing novel silicon photonic devices for telecommunications has generated a vast knowledge base that is now being leveraged for developing sophisticated photonic sensors. Silicon photonic sensors seek to exploit the strong confinement of light in nano-waveguides to transduce changes in physical state to changes in resonance frequency. In the case of thermometry, the thermo-optic coefficient, i.e., changes in refractive index due to temperature, causes the resonant frequency of the photonic device such as a Bragg grating to drift with temperature. We are developing a suite of photonic devices that leverage recent advances in telecom compatible light sources to fabricate cost-effective photonic temperature sensors, which can be deployed in a wide variety of settings ranging from controlled laboratory conditions, to the noisy environment of a factory floor or a residence. In this manuscript, we detail our protocol for the fabrication and testing of photonic thermometers.

0 Reads | 0 Citations
2018
Aug
29
Published new article




Article

Assessing Radiation Hardness of Silicon Photonic Sensors

Published: 29 August 2018 by Springer Nature in Scientific Reports

doi: 10.1038/s41598-018-31286-9

In recent years, silicon photonic platforms have undergone rapid maturation enabling not only optical communication but complex scientific experiments ranging from sensors applications to fundamental physics investigations. There is considerable interest in deploying photonics-based communication and science instruments in harsh environments such as outer space, where radiation damage is a significant concern. In this study, we have examined the impact of cobalt-60 γ-ray radiation up to 1 megagray (MGy) absorbed dose on silicon photonic devices. We do not find any systematic impact of radiation on passivated devices, indicating the durability of passivated silicon devices under harsh conditions.

0 Reads | 0 Citations
2018
Jul
01
Published new article




Article

Humidity responsive photonic sensor based on a carboxymethyl cellulose mechanical actuator

Published: 01 July 2018 by Elsevier BV in Sensors and Actuators B: Chemical

doi: 10.1016/j.snb.2018.03.065

We describe an intuitive and simple method for exploiting humidity-driven volume changes in carboxymethyl cellulose (CMC) to fabricate a humidity responsive actuator on a glass fiber substrate. We optimize this platform to generate a photonic-based humidity sensor where CMC coated on a fiber optic containing a fiber Bragg grating (FBG) actuates a mechanical strain in response to humidity changes. The humidity-driven mechanical deformation of the FBG results in a large linear change in Bragg resonance wavelength over the relative humidity range of 5%–40%. The measurement uncertainty over this relative humidity range is ± 2% (k = 1).

0 Reads | 1 Citations
2018
Jul
01
Published new article




Article

Review Article: Quantum-based vacuum metrology at the National Institute of Standards and Technology

Published: 01 July 2018 by American Vacuum Society in Journal of Vacuum Science & Technology A

doi: 10.1116/1.5033568

The measurement science in realizing and disseminating the unit for pressure in the International System of Units, the pascal (Pa), has been the subject of much interest at the National Institute of Standards and Technology (NIST). Modern optical-based techniques for pascal metrology have been investigated, including multiphoton ionization and cavity ringdown spectroscopy. Work is ongoing to recast the pascal in terms of quantum properties and fundamental constants and in doing so make vacuum metrology consistent with the global trend toward quantum-based metrology. NIST has ongoing projects that interrogate the index of refraction of a gas using an optical cavity for low vacuum, and count background particles in high vacuum to extreme high vacuum using trapped laser-cooled atoms.

0 Reads | 1 Citations
2018
May
17
Published new article






Quantum-based vacuum metrology at NIST

Published: 17 May 2018 by ArXiv

doi:

The measurement science in realizing and disseminating the unit for pressure in the International System of Units (SI), the pascal (Pa), has been the subject of much interest at the National Institute of Standards and Technology (NIST). Modern optical-based techniques for pascal metrology have been investigated, including multi-photon ionization and cavity ringdown spectroscopy. Work is ongoing to recast the pascal in terms of quantum properties and fundamental constants and in so doing, make vacuum metrology consistent with the global trend toward quantum-based metrology. NIST has ongoing projects that interrogate the index of refraction of a gas using an optical cavity for low vacuum, and count background particles in high vacuum to extreme high vacuum using trapped laser-cooled atoms.

0 Reads | 0 Citations
2018
Mar
13
Published new article




Article

Towards traceable transient pressure metrology

Published: 13 March 2018 by IOP Publishing in Metrologia

doi: 10.1088/1681-7575/aaad1b

We describe our progress in developing the infrastructure for traceable transient measurements of pressure. Towards that end, we have built and characterized a dual diaphragm shock tube that allows us to achieve shock amplitude reproducibility of approximately 2.3 % for shocks with Mach speeds ranging from 1.26 to 1.5. In this proof-of-concept study we use our shock tube to characterize the dynamic response of photonic sensors embedded in polydimethylsiloxane (PDMS), a material of choice for soft tissue phantoms. Our results indicate that the PDMS-embedded photonic sensors response to shock evolves over tens to hundreds of microseconds time scale making it a useful system for studying transient pressures in soft tissue.

1 Reads | 0 Citations
2018
Mar
01
Published new article




Article

3D-Printed Acrylonitrile Butadiene Styrene-Metal Organic Framework Composite Materials and Their Gas Storage Properties

Published: 01 March 2018 by Mary Ann Liebert Inc in 3D Printing and Additive Manufacturing

doi: 10.1089/3dp.2017.0067

Metal organic framework materials (MOFs) have been primarily recognized for their ability to promote selective storage of gas molecules. In their as-synthesized (powdered) form, MOFs are not easily processed for use in end-devices where their properties might be exploited. Composites have been produced in which either zeolite imidazolate framework-8 (ZIF-8) or HKUST-1 (also known as MOF-199 and Cu-BTC) has been incorporated into acrylonitrile butadiene styrene (ABS). These composites were then 3D printed using a conventional, commercially available 3D printer. Although many MOFs suffer from instability in humid environments, each of the MOFs in our study maintains its structure within the ABS composite even on soaking in water. Moreover, the MOFs maintain their nitrogen adsorption capacities within the composites. The retention of MOF gas adsorption properties within the composite is promising in that these materials can be optimized (MOF, polymer, and 3D-printed geometry) for a number of applications, including gas storage, filtering, sensing, and catalysis.

0 Reads | 2 Citations
2018
Jan
01
Published new article






Optomechanical Quantum Thermometry

Published: 01 January 2018 by The Optical Society in CLEO: 2015

doi: 10.1364/cleo_at.2018.jf2b.5

We demonstrate quantum-backaction-noise-calibrated Brownian motion thermometry as a metrological application of quantum optomechanics. We present recent work as well as on-going efforts to enhance the bandwidth, sensitivity, and range of these devices.

0 Reads | 0 Citations
2017
Dec
02
Published new article




Article

Towards Replacing Resistance Thermometry with Photonic Thermometry

Published: 02 December 2017 by Elsevier BV in Sensors and Actuators A: Physical

doi: 10.1016/j.sna.2017.11.055

Resistance thermometry provides a time-tested method for taking temperature measurements that has been painstakingly developed over the last century. However, fundamental limits to resistance-based approaches along with a desire to reduce the cost of sensor ownership and increase sensor stability has produced considerable interest in developing photonic temperature sensors. Here we demonstrate that silicon photonic crystal cavity-based thermometers can measure temperature with uncertainities of 175 mK (k = 1), where uncertainties are dominated by ageing effects originating from the hysteresis in the device packaging materials. Our results, a ≈ 4-fold improvement over recent developments, clearly demonstate the rapid progress of silicon photonic sensors in replacing legacy devices.

0 Reads | 0 Citations
2017
Oct
19
Published new article






Radiation Hardness of Fiber Bragg Grating Thermometers

Published: 19 October 2017 by ArXiv

doi:

Photonics sensing has long been valued for its tolerance to harsh environments where traditional sensing technologies fail. As photonic components continue to evolve and find new applications, their tolerance to radiation is emerging as an important line of inquiry. Here we report on our investigation of the impact of gamma-ray exposure on the temperature response of fiber Bragg gratings. At 25 degrees C, exposures leading to an accumulated dose of up to 600 kGy result in complex dose-dependent drift in Bragg wavelength, significantly increasing the uncertainty in temperature measurements obtained if appreciable dose is delivered over the measurement interval. We note that temperature sensitivity is not severely impacted by the integrated dose, suggesting such devices could be used to measure relative changes in temperature.

0 Reads | 0 Citations
2017
Oct
19
Published new article




Article

Toward 3D Printed Hydrogen Storage Materials Made with ABS-MOF Composites

Published: 19 October 2017 by Wiley in Polymers for Advanced Technologies

doi: 10.1002/pat.4197

The push to advance efficient, renewable, and clean energy sources has brought with it an effort to generate materials that are capable of storing hydrogen. Metal-organic framework materials (MOFs) have been the focus of many such studies as they are categorized for their large internal surface areas. We have addressed one of the major shortcomings of MOFs (their processibility) by creating and 3D printing a composite of acrylonitrile butadiene styrene (ABS) and MOF-5, a prototypical MOF, which is often used to benchmark H2 uptake capacity of other MOFs. The ABS-MOF-5 composites can be printed at MOF-5 compositions of 10% and below. Other physical and mechanical properties of the polymer (glass transition temperature, stress and strain at the breaking point, and Young’s modulus) either remain unchanged or show some degree of hardening due to the interaction between the polymer and the MOF. We do observe some MOF-5 degradation through the blending process, likely due to the ambient humidity through the purification and solvent casting steps. Even with this degradation, the MOF still retains some of its ability to uptake H2, seen in the ability of the composite to uptake more H2 than the pure polymer. The experiments and results described here represent a significant first step toward 3D printing MOF-5-based materials for H2 storage.

0 Reads | 5 Citations
2017
Oct
04
Published new article






Towards Replacing Resistance Thermometry with Photonic Thermometry

Published: 04 October 2017 by ArXiv

doi:

Resistance thermometry provides a time-tested method for taking temperature measurements that has been painstakingly developed over the last century. However, fundamental limits to resistance-based approaches along with a desire to reduce the cost of sensor ownership and increase sensor stability has produced considerable interest in developing photonic temperature sensors. Here we demonstrate that silicon photonic crystal cavity-based thermometers can measure temperature with uncertainities of 175 mK (k = 1), where uncertainties are dominated by ageing effects originating from the hysteresis in the device packaging materials. Our results, a 4-fold improvement over recent developments, clearly demonstate the rapid progress of silicon photonic sensors in replacing legacy devices.

0 Reads | 0 Citations
2017
Apr
07
Published new article






Toward 3D printed hydrogen storage materials made with ABS-MOF composites

Published: 07 April 2017 by Center for Open Science in engrXiv

doi: 10.31224/osf.io/4utb2

The push to advance efficient, renewable, and clean energy sources has brought with it an effort to generate materials that are capable of storing hydrogen. Metal-organic framework materials (MOFs) have been the focus of many such studies as they are categorized for their large internal surface areas. We have addressed one of the major shortcomings of MOFs (their processibility) by creating and 3D printing a composite of acrylonitrile butadiene styrene (ABS) and MOF-5, a prototypical MOF, which is often used to benchmark H2 uptake capacity of other MOFs. The ABS-MOF-5 composites can be printed at MOF-5 compositions of 10% and below. Other physical and mechanical properties of the polymer (glass transition temperature, stress and strain at the breaking point, and Young’s modulus) either remain unchanged or show some degree of hardening due to the interaction between the polymer and the MOF. We do observe some MOF-5 degradation through the blending process, likely due to the ambient humidity through the purification and solvent casting steps. Even with this degradation, the MOF still retains some of its ability to uptake H2, seen in the ability of the composite to uptake more H2 than the pure polymer. The experiments and results described here represent a significant first step toward 3D printing MOF-5-based materials for H2 storage.

0 Reads | 0 Citations
2017
Jan
01
Published new article






Optomechanical Quantum Correlations

Published: 01 January 2017 by The Optical Society in CLEO: 2015

doi: 10.1364/cleo_qels.2017.jth3g.4

We present methods to measure optical quantum correlations arising from an optomechanical interaction even when large classical noise sources are present. We demonstrate quantum-backaction-noise-calibrated Brownian motion thermometry as a metrological application of quantum optomechanics.

0 Reads | 0 Citations
2017
Jan
01
Published new article






Impact of Varying Vacuum Levels on Self-Heating in Photonic Thermometers

Published: 01 January 2017 by The Optical Society in CLEO: 2015

doi: 10.1364/cleo_at.2017.jth4m.2

Here we examine the impact of vacuum levels on self-heating in photonic crystal cavity thermometers . Our results suggest that background gas pressure has a negligible impact on self-heating correction to the temperature-wavelength calibration.

0 Reads | 0 Citations
2017
Jan
01
Published new article






Humidity Responsive Photonic Sensor based on a Carboxymethyl Cellulose Mechanical Actuator

Published: 01 January 2017 by American Chemical Society (ACS)

doi: 10.26434/chemrxiv.5492728.v1

We describe an intuitive and simple method for exploiting humidity-driven volume changes in carboxymethyl cellulose (CMC) to fabricate a humidity responsive actuator on a glass fiber substrate. We optimize this platform to generate a photonic-based humidity sensor where CMC coated on a fiber optic containing a fiber Bragg grating (FBG) actuates a mechanical strain in response to humidity changes. The humidity-driven mechanical deformation of the FBG results in a large linear change in Bragg resonance wavelength over the humidity range of 5 %RH (relative humidity) to 40 %RH. The measurement uncertainty over this range is ± 2 %RH.

0 Reads | 0 Citations
2017
Jan
01
Published new article






Humidity Responsive Photonic Sensor based on a Carboxymethyl Cellulose Mechanical Actuator

Published: 01 January 2017 by American Chemical Society (ACS)

doi: 10.26434/chemrxiv.5492728

We describe an intuitive and simple method for exploiting humidity-driven volume changes in carboxymethyl cellulose (CMC) to fabricate a humidity responsive actuator on a glass fiber substrate. We optimize this platform to generate a photonic-based humidity sensor where CMC coated on a fiber optic containing a fiber Bragg grating (FBG) actuates a mechanical strain in response to humidity changes. The humidity-driven mechanical deformation of the FBG results in a large linear change in Bragg resonance wavelength over the humidity range of 5 %RH (relative humidity) to 40 %RH. The measurement uncertainty over this range is ± 2 %RH.

0 Reads | 0 Citations
2017
Jan
01
Published new article






Toward 3D printed hydrogen storage materials made with ABS-MOF composites

Published: 01 January 2017

doi: 10.17605/osf.io/4utb2

The push to advance efficient, renewable, and clean energy sources has brought with it an effort to generate materials that are capable of storing hydrogen. Metal-organic framework materials (MOFs) have been the focus of many such studies as they are categorized for their large internal surface areas. We have addressed one of the major shortcomings of MOFs (their processibility) by creating and 3D printing a composite of acrylonitrile butadiene styrene (ABS) and MOF-5, a prototypical MOF, which is often used to benchmark H2 uptake capacity of other MOFs. The ABS-MOF-5 composites can be printed at MOF-5 compositions of 10% and below. Other physical and mechanical properties of the polymer (glass transition temperature, stress and strain at the breaking point, and Young’s modulus) either remain unchanged or show some degree of hardening due to the interaction between the polymer and the MOF. We do observe some MOF-5 degradation through the blending process, likely due to the ambient humidity through the purification and solvent casting steps. Even with this degradation, the MOF still retains some of its ability to uptake H2, seen in the ability of the composite to uptake more H2 than the pure polymer. The experiments and results described here represent a significant first step toward 3D printing MOF-5-based materials for H2 storage.

0 Reads | 0 Citations
2016
Oct
25
Published new article




Article

Gas Uptake of 3-D Printed Acrylonitrile Butadiene Styrene (ABS) Using a Vacuum Apparatus Designed for Absorption and Des...

Published: 25 October 2016 by American Vacuum Society in Journal of Vacuum Science & Technology A

doi: 10.1116/1.4965304

We describe a vacuum apparatus for determining the outgassing rate into vacuum, the diffusion coefficient, and the amount of gas absorbed for various materials. The diffusion coefficient is determined from a model applied to time-dependent desorption data taken using a throughput method. We used this method to determine the diffusion coefficient, D, for H2O in 3-D printed acrylonitrile butadiene styrene (ABS). We found DH2O = 8.3 × 10−8 cm2/s ± 1.3 × 10−8 cm2/s (k = 1; 67% confidence interval) at 23.2 °C. This result was compared to the diffusion coefficient determined another by a gravimetric method, in which the sample weight was monitored as it absorbed gas from the atmosphere. The two methods agreed to within 3%, which is well within the uncertainty of the measurement. We also found that at least 80% of the atmospheric gas (air) absorbed by the ABS is water. The total amount of all atmospheric gas absorbed by ABS was about 0.35% by weight when exposed to ambient air in the laboratory, which was at a pressure of 101 kPa with a relative humidity of 57% at 22.2 °C.

0 Reads | 2 Citations
2016
Oct
01
Published new article






Ring resonator thermometry

Published: 01 October 2016 by Institute of Electrical and Electronics Engineers (IEEE) in 2016 IEEE Photonics Conference (IPC)

doi: 10.1109/ipcon.2016.7830998

We report on our study of a temperature response of ring resonator based sensors and their interchangeability over a wide temperature range. Our results suggest that with a proper fabrication process control the interchangeability in photonic thermometers can be on a 0.2 °C tolerance band.

0 Reads | 0 Citations
2016
May
12
Published new article




Article

Fiber Bragg Grating Based Thermometry

Published: 12 May 2016 by Informa UK Limited in NCSLI Measure

doi: 10.1080/19315775.2015.11721744

In recent years there has been considerable interest in developing photonic temperature sensors such as the Fiber Bragg gratings (FBG) as an alternative to resistance thermometry. In this study we examine the thermal response of FBGs over the temperature range of 233 K to 393 K. We demonstrate, in hermetically sealed dry Argon environment, FBG devices show a quadratic dependence on temperature with expanded uncertainties (k=2) of ≈500 mK. Our measurements indicate that the combined measurement uncertainty is dominated by uncertainty in determining peak center fitting and thermal ageing of polyimide coated fibers.

0 Reads | 1 Citations
2016
Apr
01
Published new article




Article

The chemical, mechanical, and physical properties of 3D printed materials composed of TiO2-ABS nanocomposites

Published: 01 April 2016 by Informa UK Limited in Science and Technology of Advanced Materials

doi: 10.1080/14686996.2016.1152879

To expand the chemical capabilities of 3D printed structures generated from commercial thermoplastic printers, we have produced and printed polymer filaments that contain inorganic nanoparticles. TiO2 was dispersed into acrylonitrile butadiene styrene (ABS) and extruded into filaments with 1.75 mm diameters. We produced filaments with TiO2 compositions of 1, 5, and 10% (kg/kg) and printed structures using a commercial 3D printer. Our experiments suggest that ABS undergoes minor degradation in the presence of TiO2 during the different processing steps. The measured mechanical properties (strain and Young’s modulus) for all of the composites are similar to those of structures printed from the pure polymer. TiO2 incorporation at 1% negatively affects the stress at breaking point and the flexural stress. Structures produced from the 5 and 10% nanocomposites display a higher breaking point stress than those printed from the pure polymer. TiO2 within the printed matrix was able to quench the intrinsic fluorescence of the polymer. TiO2 was also able to photocatalyze the degradation of a rhodamine 6G in solution. These experiments display chemical reactivity in nanocomposites that are printed using commercial 3D printers, and we expect that our methodology will help to inform others who seek to incorporate catalytic nanoparticles in 3D printed structures.

0 Reads | 11 Citations
2016
Mar
24
Published new article






Fiber Bragg Grating Based Thermometry

Published: 24 March 2016 by ArXiv

doi:

In recent years there has been considerable interest in developing photonic temperature sensors such as the Fiber Bragg gratings (FBG) as an alternative to resistance thermometry. In this study we examine the thermal response of FBGs over the temperature range of 233 K to 393 K. We demonstrate, in a hermetically sealed dry Argon environment, that FBG devices show a quadratic dependence on temperature with expanded uncertainties (k = 2) of ~500 mK. Our measurements indicate that the combined measurement uncertainty is dominated by uncertainty in determining the peak center fitting and by thermal aging of polyimide coated fibers.

0 Reads | 0 Citations
2016
Mar
24
Published new article






Towards Photonics Enabled Quantum Metrology of Temperature, Pressure and Vacuum

Published: 24 March 2016 by ArXiv

doi:

This chapter presents a brief overview of photonic sensor and standards development that is currently undergoing in the thermodynamic metrology group at NIST in the areas of temperature, pressure, vacuum and time-resolved pressure measurements.

0 Reads | 0 Citations
2016
Jan
01
Published new article






Thermometry with Optomechanical Cavities

Published: 01 January 2016 by The Optical Society in CLEO: 2015

doi: 10.1364/cleo_si.2016.stu1h.2

The thermally-driven motion of a nanomechanical resonator may be employed as an absolute thermometer. We experimentally measure radiation pressure shot noise induced quantum correlations to absolutely calibrate the motional signal transduced onto an optical probe.

0 Reads | 0 Citations
2016
Jan
01
Published new article






Precision Spectroscopy to Enable Traceable Dynamic Measurements of Pressure

Published: 01 January 2016 by The Optical Society in Conference on Lasers and Electro-optics : (CLEO). Conference on Lasers and Electro-optics

doi: 10.1364/CLEO_AT.2016.ATu1J.1

We present recent work aimed at creating a standard for the dynamic measurement of pressure. A near-IR laser spectroscopy system is demonstrated for measuring 8 cm−1 in 50 μs with a 4 kHz repetition rate.

0 Reads | 0 Citations
2016
Jan
01
Published new article






Chip-Packaged Silicon Photonic Nanoscale Thermometers

Published: 01 January 2016 by The Optical Society in CLEO: 2015

doi: 10.1364/cleo_at.2016.aw1j.6

We report on the development of on-chip integrated packaged nanoscale silicon photonic temperature sensors capable of detecting temperature difference as small as 70 μK, thus showing the potential to replace legacy resistance thermometers.

0 Reads | 0 Citations
2015
Sep
01
Published new article




Article

On-chip silicon waveguide Bragg grating photonic temperature sensor.

Published: 01 September 2015 in Optics Letters

doi:

Resistance thermometry is a time-tested method for taking temperature measurements. In recent years, fundamental limits to resistance-based approaches have spurred considerable interest in developing photonic temperature sensors as a viable alternative. In this study, we demonstrate that our photonic thermometer, which consists of a silicon waveguide integrated with a Bragg grating, can be used to measure temperature changes over the range of 5°C-160°C, with a combined expanded uncertainty [k=2, 95% confidence level] of 1.25°C. Computational modeling of the sensor predicts the resonance wavelength and effective refractive index within 4% of the measured value.

0 Reads | 1 Citations
2015
Aug
17
Published new article




Article

On-chip silicon waveguide Bragg grating photonic temperature sensor

Published: 17 August 2015 by The Optical Society in Optics Letters

doi: 10.1364/ol.40.003934

Resistance thermometry is a time-tested method for taking temperature measurements. In recent years, fundamental limits to resistance-based approaches have spurred considerable interest in developing photonic temperature sensors as a viable alternative. In this study, we demonstrate that our photonic thermometer, which consists of a silicon waveguide integrated with a Bragg grating, can be used to measure temperature changes over the range of 5°C–160°C, with a combined expanded uncertainty [k=2, 95% confidence level] of 1.25°C. Computational modeling of the sensor predicts the resonance wavelength and effective refractive index within 4% of the measured value.

3 Reads | 12 Citations
2015
Aug
06
Published new article






Fabrication and Characterization of On-Chip Integrated Silicon Photonic Bragg Grating and Photonic Crystal Cavity Thermo...

Published: 06 August 2015 by ArXiv

doi:

We report on the fabrication and characterization of photonic-based nanothermometers, a silicon photonic Bragg grating and photonic crystal cavity. When cladded with silicon dioxide layer the sensors have at least eight times better sensitivity compared to the sensitivity of conventional fiber Bragg grating sensors. We demonstrate that these photonic thermometers are a viable temperature sensing solution.

0 Reads | 0 Citations
2015
Aug
06
Published new article






Developing Microwave Photonic Temperature Sensors

Published: 06 August 2015 by ArXiv

doi:

In recent years there has been considerable interest in exploiting the temperature dependence of sapphire whispering gallery mode frequency to develop a mechanically stable, high accuracy temperature sensor. Disk-resonator-based devices have been demonstrated to measure temperature with .01 K or better accuracy in the temperature range of 273 K to 373 K. Here we have utilized automated data acquisition and processing to rapidly evaluate a mechanically-stabilized sapphire whispering gallery mode resonator based on a hollow cylinder configuration.

0 Reads | 0 Citations
2015
Aug
05
Published new article






On-Chip Silicon Waveguide Bragg Grating Photonic Temperature Sensor

Published: 05 August 2015 by ArXiv

doi:

Resistance thermometry is a time-tested method for taking temperature measurements. In recent years fundamental limits to resistance-based approaches spurred considerable interest in developing photonic temperature sensors as a viable alternative. In this study we demonstrate that our photonic thermometer, which consists of a silicon waveguide integrated with a Bragg grating, can be used to measure temperature changes over the range from 5 C to 160 C with a combined expanded uncertainty [k = 2 ; 95% confidence level] of 1.25 degree C. The computational modeling of the sensor predicts the resonance wavelength and effective refractive index within 4% of the measured value.

0 Reads | 0 Citations
2015
Aug
05
Published new article






Fiber Bragg Gratings Embedded in 3D-Printed Scaffolds

Published: 05 August 2015 by ArXiv

doi:

In recent years there has been considerable interest in utilizing embedded fiber optic based sensors for fabricating smart materials. One of the primary motivations is to provide real-time information on the structural integrity of the material so as to enable proactive actions that prevent catastrophic failure. In this preliminary study we have examined the impact of embedding on the temperature-dependent response of fiber Bragg gratings.

1 Reads | 0 Citations
2015
Jun
01
Published new article




Article

Fiber Bragg Gratings Embedded in 3D-Printed Scaffolds

Published: 01 June 2015 by Informa UK Limited in NCSLI Measure

doi: 10.1080/19315775.2015.11721724

In recent years there has been considerable interest in utilizing embedded fiber optic based sensors for fabricating smart materials. One of the primary motivations is to provide real-time information on the structural integrity of the material so as to enable proactive actions that prevent catastrophic failure. In this preliminary study we have examined the impact of embedding on the temperature-dependent response of fiber Bragg gratings (FBG). Our results indicate that scaffold strain has a significant impact on the embedded sensor's temperature response. Thus, the use of embedded sensors will require the development of in corpus techniques that can calibrate sensors while they are embedded.

2 Reads | 1 Citations
2015
May
13
Published new article






On-chip silicon photonic thermometers: from waveguide Bragg grating to ring resonators sensors

Published: 13 May 2015 by SPIE-Intl Soc Optical Eng in Advanced Environmental, Chemical, and Biological Sensing Technologies XII

doi: 10.1117/12.2176666

0 Reads | 0 Citations
2015
Jan
01
Published new article






Characterization of Ring Resonator Structures for Applications in Photonic Thermometry

Published: 01 January 2015 by The Optical Society in Advanced Photonics 2018 (BGPP, IPR, NP, NOMA, Sensors, Networks, SPPCom, SOF)

doi: 10.1364/sensors.2015.set4c.6

We have systematically examined the impact of structural parameters on silicon ring resonator-based photonic temperature sensor's performance by systematically varying the ring radius, waveguide width and gap separating the ring and waveguide.

0 Reads | 1 Citations
2015
Jan
01
Published new article






Fabry-Perrot Cavity-based Silicon Photonic Thermometers with Ultra-small Footprint and High Sensitivity

Published: 01 January 2015 by The Optical Society in Advanced Photonics 2018 (BGPP, IPR, NP, NOMA, Sensors, Networks, SPPCom, SOF)

doi: 10.1364/sensors.2015.set4c.4

In this work we report on the development of silicon photonic temperature sensors with ultra-small footprint and high temperature sensitivity as an alternative solution to legacy-based resistance thermometers.

0 Reads | 1 Citations
2014
Mar
20
Published new article






Quantum Metrology

Published: 20 March 2014 by Informa UK Limited in Dekker Encyclopedia of Nanoscience and Nanotechnology, Third Edition

doi: 10.1081/e-enn3-120054060

0 Reads | 0 Citations
2014
Feb
10
Published new article




Article

Ultra-sensitive chip-based photonic temperature sensor using ring resonator structures.

Published: 10 February 2014 in Optics Express

doi:

Resistance thermometry provides a time-tested method for taking temperature measurements. However, fundamental limits to resistance-based approaches has produced considerable interest in developing photonic temperature sensors to leverage advances in frequency metrology and to achieve greater mechanical and environmental stability. Here we show that silicon-based optical ring resonator devices can resolve temperature differences of 1 mK using the traditional wavelength scanning methodology. An even lower noise floor of 80 μK for measuring temperature difference is achieved in the side-of-fringe, constant power mode measurement.

0 Reads | 0 Citations
2014
Feb
03
Published new article




Article

Ultra-sensitive chip-based photonic temperature sensor using ring resonator structures

Published: 03 February 2014 by The Optical Society in Optics Express

doi: 10.1364/oe.22.003098

Resistance thermometry provides a time-tested method for taking temperature measurements. However, fundamental limits to resistance-based approaches has produced considerable interest in developing photonic temperature sensors to leverage advances in frequency metrology and to achieve greater mechanical and environmental stability. Here we show that silicon-based optical ring resonator devices can resolve temperature differences of 1 mK using the traditional wavelength scanning methodology. An even lower noise floor of 80 μK for measuring temperature difference is achieved in the side-of-fringe, constant power mode measurement.

4 Reads | 13 Citations
2013
Jan
01
Published new article






Photonic temperature sensor based on microring resonators

Published: 01 January 2013 by The Optical Society in CLEO: 2015

doi: 10.1364/cleo_si.2013.cm4o.1

We present an experimental analysis on photonic temperature sensor based on microring resonators, and we show that the sensitivity can be better than 40μK, which is limited by the noise of instrument in use.

0 Reads | 0 Citations
2015
Jul
13
Conference participation




Zeeshan Ahmed participated at conference 4th International Symposium on Sensor Science.

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