Atomic, Molecular, Optical, and Plasma Physics Division focuses on fundamental interactions of atoms, molecules, optical media, and charged particles to laser lights, x rays, or other novel sources of electric and magnetic fields. These fundamental interactions are important to understand natural phenomena such as solar flares, the birth of stars, and lightning, as well as to advance modern technology such as the development of efficient light bulbs, plasma televisions, lasers, and modern infrastructures for quantum computers. We will have one invited talk from an expert in the field and several contributed talks from young scholars.
Light manipulation with nanostructures
Photonic crystals, metamaterials and metasurfaces are nanophotonic structures that demonstrate novel avenues of light manipulation at wavelength and subwavelength scales enabling phenomena like high Purcell factors, topological behavior, anomalous refraction or flat lensing. This talk will discuss some selected work performed at Sandia on some of these topics at Sandia involving various semiconductors (III-V, III-nitrides, Si) and dielectrics (e.g., TiO2)across infrared to visible wavelengths.
Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. The views expressed in the article do not necessarily represent the views of the U.S. Department of Energy or the United States Government.
Please look below for detailed schedule.
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Abstract Number: ANPA2024-N0004 Presenting Author: Roshan Chalise Presenter's Affiliation: Central Department of Physics, Tribhuvan University Title: Development and Characterization of Gliding Arc Plasma Jet (GAPJ) Location: In-Person Presentation, CDP Show/Hide Abstract In this work, we present the development of an atmospheric pressure gliding arc plasma jet (GAPJ) that operates in ambient air to generate non-thermal plasma. This technology, developed from our locally available material, holds potential applications for treating the designated substrate region. There is a direct relationship between airflow rate and jet length. The discharge was characterized using electrical and optical methods, and it was discovered that airflow and applied voltage impacted the discharge's electrical and optical parameters, including power, gas flow rate, and applied voltage. The produced plasma is contained to create a plasma plume and has potential uses in specific fields of decontamination and sterilizing in the food industry, pharmaceutical, and medical sectors.
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Abstract Number: ANPA2024-N0005 Presenting Author: Santosh Dhungana Presenter's Affiliation: Tribhuvan University Title: Electrical and Optical Characterization of Knife Shaped Gliding Arc Discharge (GAD) System and Its Application on PAW Production and Seed Treatment Location: In-Person Presentation, CDP Show/Hide Abstract GAD is an auto-oscillating discharge that starts between electrodes of divergent geometry through the force of the laminar or turbulent flow of gas or air. In this discharge system, a breakdown of atmospheric gas occurs at the shortest gap between the two divergent electrodes. It is a simple and inexpensive way to generate non-thermal plasma and has various applications in the fields of material processing, gas conversion, medical sterilization, and agriculture. In this study, the GAD system was constructed from different metals, and their electrical and optical characteristics were studied on the basis of gas flow rates and applied voltages. Plasma activated water (PAW) generated from GAD discharge system is characterized. A significant change in physiochemical properties of water is observed. Direct treatment of seed by GAD has changed the surface properties of seed. This is illustrated by contact angle measurement, conductivity tests, and FTIR analysis of seeds.
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Abstract Number: ANPA2024-N00019 Presenting Author: Samjhana Dahal Presenter's Affiliation: Tribhuvan University Title: GERMINATION AND SEEDLING GROWTH ENHANCEMENT OF TIMUR SEED (Zanthoxylum armatum) BY USING COLD ATMOSPHERIC PRESSURE PLASMA Location: Poster Presentation Show/Hide Abstract Timur is a plant native to the Himalayan region and it is valued for its intense citrusy and peppery flavor, used in culinary and traditional practices. In this work, we have used gliding arc discharge for direct treatment of the Timur seed (Zanthoxylum armatum) and used plasma-activated water, prepared by cylindrical dielectric barrier discharge and gliding arc discharge, to irrigate the plants, aiming to enhance germination and seedling growth. The plasma sources are characterized through electrical and optical characterization methods. From spectrometer, electron temperature of cylindrical dielectric barrier discharge and gliding arc discharge is found to be 1.41 eV and 1.66 eV with plasma density found to be 8.17 × 10^18 m^ −3 and 5.48 × 10^17 m ^−3 , respectively. Plasma treatment increases the temperature, total dissolved solids, electrical conductivity, and oxidation-reduction potential of the plasma-activated water with the activation time; however, the potential of hydrogen
decreases. In addition, it has been observed that nitrate concentration is notably higher than nitrite concentration. It has been observed that the direct application of plasma on Timur seeds results in changes to the seeds, particularly in their surface properties and wettability. The results showed that the wettability of seeds using two minutes (min) plasma-activated water increases the most compared to the untreated seeds and other treatment times. Although germination enhancement of the Timur seeds is not achieved in the laboratory condition, plasma-activated water positively impacts root and shoot growth, as well as in the retention of chlorophyll content (or greenness) of leaves. A treatment time of four minutes using cylindrical dielectric barrier discharge and two minutes using plasma jet
is found most favorable. The positive impact of plasma on Timur plants can be studied further to enhance germination, seedling growth, and ultimately, fruit yield, making it viable for agricultural applications in real field conditions.
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Abstract Number: ANPA2024-N00020 Presenting Author: Saroj Pandeya Presenter's Affiliation: Central department of Physics Title: OBLIQUE PROPAGATION OF DUST-ION ACOUSTIC WAVES IN 3D3V QUANTUM MAGNETIZED DUSTY PLASMA WITH ELECTRON PRESSURE ANISOTROPY Location: Poster Presentation Show/Hide Abstract Due to the wide range of growing applications, the understanding of wave characteristics in magnetized quantum dusty plasma is inevitable for unfolding the mystery of dense astrophysical environments, laser-produced plasma, micro and nano-scale physics. Moreover, the emerging potential of quantum information science utilizing ultra-cold quantum plasma has gained significant interest. In this study, we employ the quantum hydrodynamic model (QHM) and reductive perturbation technique to investigate features of nonlinear oblique propagation of dust-ion acoustic waves (DIAWs) in account of electron pressure anisotropy. It is found that solitary wave structure including phase velocity, solitary wave's width, and amplitude are affected by the pressure anisotropy and obliqueness of wave propagation. The magnitude of the magnetic field affects the width of solitary waves. The decaying of solitary wave energy as the function of time indicates that the waves get damped as time evolves. Moreover, we have compared our analytical results with the results obtained from the finite-difference method and estimated the percentage deviation, which is less than 10%. Our findings provide valuable insights into the propagation of dust-ion acoustic waves, particularly in astrophysical dusty plasmas.
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Abstract Number: ANPA2024-N00018 Presenting Author: Ramesh Khanal Presenter's Affiliation: Student Title: PLASMA-WALL INTERACTION MECHANISM AND DUST PARTICLES CHARGING FOR MAGNETIZED PLASMA EXPOSED WITH TUNGSTEN AND CARBON ELECTRON EMITTING SURFACES Location: Poster Presentation Show/Hide Abstract The understanding of plasma-wall transition characteristics is crucial when the quasineutral plasma interacts with a material surface via a non-neutral plasma sheath which determines the flow of particles flux and energy towards the surface. This interaction determines the lifetime of plasma-facing materials. In this study, we have used kinetic theory to investigate the magnetized plasma-wall interaction and dust charging model in the presence of secondary electron emission from material surfaces (tungsten and carbon). The kinetic Bohm sheath condition has been extended in the presence of secondary electron emission and it is found that ion flow at the presheath-sheath boundary and wall potential get affected by the flux of electron emission. The variation of sheath potential, particle densities, and energy of positive ions towards the surface are significantly changed by the concentration of secondary electron emission. The flow of ion's energy toward the surfaces determines the magnitude of ion particle reflection, absorption, and sputtering yield for the selected materials. Furthermore, the sputtered tungsten and carbon dust particles in plasma are getting charged and the evolution of dust charge in the plasma-wall transition region and dust particle levitation have been systematically presented.
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Abstract Number: ANPA2024-N00017 Presenting Author: Nisha Kaucha Presenter's Affiliation: Patan Multiple Campus Title: CHARACTERIZATION OF COLD ATMOSPHERIC PLASMA: PRODUCTION OF REACTIVE SPECIES AND ITS ANTIBACTERIAL PROPERTIES. Location: Poster Presentation Show/Hide Abstract The antibacterial capabilities of cold atmospheric plasma are significantly influenced by the presence of reactive species in the plasma discharge. The cold atmospheric plasma has multiple applications in biomedicine. Its applications in the contemporary world are rapidly growing and now included sterilization, disinfection, cancer treatment, and many more. In light of this, the primary focus of this dissertation was on the creation of reactive species and study antibacterial properties of plasma, with the cold atmospheric plasma (CAP) being characterized through the use of electrical and optical techniques. Oscilloscope helped to estimate value of electron density, whereas, a spectrometer measured the nitrogen (III) spectral lines with varying wavelengths and intensities. It was useful for figuring out the plasma discharge's electron temperature. To calculate the electron temperature, one used the Boltzmann plot approach. Electron temperature and density were useful in determining the plasma's performance. Gliding arc discharge (GAD), which used 'air' as process gas and had a flow rate of 15 lpm, a high voltage power supply of 12 KV, and an operating frequency of 50 Hz, was used for CAP discharge.\\
Two separate bacterial samples were obtained and cultured in Nutrients agar for a few days in order to examine the antibacterial properties: one gram negative sample, Escherichia coli-ATCC 25923, and the other gram positive sample, Staphylococcus aureus-25922. After that, it was treated with plasma for different amounts of time, which aided in the establishment of a Zone of inhibition in treated areas demonstrating the antibacterial efficacy of plasma. Additionally, well water samples were subjected to cold plasma treatment to study Physico-chemical parameters.
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Abstract Number: ANPA2024-N00016 Presenting Author: Kashi Ram Panday Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kirtipur Title: ADSORPTION OF KHARIDHUNGA(TALCSTONE)AND KAMEROMATO (CLAY) IN DISTILLED WATER AND ACETONE Location: Poster Presentation Show/Hide Abstract Nanoparticles are common in nature and are the subject of research in many areas, including chemistry, physics, geology, and biology. Nanoparticles are of great interest because of the transition between bulk materials and atomic or molecular structures, they display behaviors that are not observed at either size. A study of FTIR and UV-Vis of kameromato and kharidhunga adsorbed in water and acetone has been carried out in this research work. For the FTIR study, kharidhunga and kameromato powder were dried in a dry air oven. After being mixed with the proper amounts of water and acetone respectively, the sample was brought in for the sonication procedure. For UV-Vis, the solution was further diluted in acetone, and for FTIR, the sample's remnant was allowed to dry naturally. The FTIR spectra of pure kharidhunga showed Mg-OH stretching and Si-O-Si symmetric stretching at 3675 cm-1 and 664 cm-1, respectively, indicating the existence of magnesium and silicate. The presence of aluminum and silicate bonding in our kameromato sample was further confirmed by the Al-OH-Al vibration and Si-O-Si stretching at 909 cm-1 and 673 cm-1 respectively, in the kameromato FTIR spectrum. In the IR spectrum of Kharidhunga in acetone, a weak peak at wavenumber 1423 cm-1 indicates the presence of C=O bonds which confirms the absorption of acetone by Kharidhunga. The UV spectrum of kameromato in acetone exhibits a prominent absorbance peak at 275 nm, demonstrating that the kameromato sample has absorbed acetone. This work will contribute to the manufacture of health-friendly cosmetics.
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Abstract Number: ANPA2024-N00015 Presenting Author: Aman Kumar Rai Presenter's Affiliation: Tribhuwan University Title: ION FLOW, SHEATH CHARACTERISTICS, AND DUST DYNAMICS OF LUNAR DUSTY PLASMA WITH SUPERTHERMAL ELECTRONS Location: Poster Presentation Show/Hide Abstract In space dusty plasma (lunar dusty plasma), the emission of electrons from the lunar surface due to solar UV radiation significantly affects the characteristics of the plasma sheath formed at the lunar surface, which is crucial to understanding the dust charging mechanism and dust dynamics of lunar dusty plasma. In this work, a steady-state collisionless ion fluid model is used for lunar dusty plasma in the presence of solar wind superthermal electrons. All the plasma parameters used during the numerical execution are consistent with the lunar dusty plasma environment. The extended form of the modified Bohm sheath criterion has been derived and it is found that ion flow at the sheath boundary and the evolution of equilibrium dust charge are significantly influenced by superthermal index of electrons, solar zenith angle, and solar wind conditions. The effect of photoelectron emission from the lunar surface and solar zenith angle on surface potential has been graphically illustrated. The electrons and positive ions are found to be decreased towards the surface; however, the decrement rate for ions is much slower than that of electrons. Moreover, the choice of superthermal electrons affects the temporal evolution of dust charge, dust charging on sheath region, dust levitation, and dust dynamics as well.
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Abstract Number: ANPA2024-N00086 Presenting Author: Bhanu Ghimire Presenter's Affiliation: University of North Caroline at Charlotte Title: Meanderline Quarter Wave Plate Location: In-Person Presentation, Fayetteville Show/Hide Abstract Meanderline grids are basically wave retarder that functions as frequency selective surface (FSS) and changes optical polarization of the incident signal. In this paper, we demonstrate the behavior of quarter-wave retarder for medium-wave infrared (MWIR) spectrum. Conversion of linear polarization incident signal at 45-degree into circular polarization have been demonstrated using finite element electromagnetic simulation. Matrices used for analysis are average power reflectance for TE and TM modes, phase retardance, axial ratio and polarization conversion ratio.
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Abstract Number: ANPA2024-N00087 Presenting Author: Chandra M. Adhikari Presenter's Affiliation: Department of Chemistry, Physics and Materials Science, Fayetteville State University, Fayetteville, NC 28301, USA Title: Effect of cavity length in Mxene-based Fabry Perot interferometer Location: In-Person Presentation, Fayetteville Show/Hide Abstract Fabry-Perot interferometers (FPIs) are optical cavities made from two parallel high reflecting surfaces with a small transmissivity used for high-resolution spectroscopy. Tuning resonance peaks varying the cavity lengths in the FPI is of great interest in optoelectronic device applications such as optical filters. To achieve this, we first make use of Maxwell’s equation to theoretically investigate the relation of transmission and reflectance of a multilayer system and determine the transmission and reflection spectra of the distributed Bragg reflectors (DBR) in the system. Taking one of the most common lowest refractive index coating materials MgF2, and relatively high refractive index material TiO2, in layers of the system, the transmission and reflection spectra of the Fabry Perot interferometer constructed from them are evaluated. The same is evaluated by replacing one of the layers with Ti3C2 and Ti2C MXenes and graphene. The optical spectra are observed as a function of cavity length to analyze the resonant peak position variation with respect to the cavity length. We noticed that the DBR system blocks the wide range of the frequency band. The cavity formed between the two DBRs causes the formation of a transmission peak within the stop band whose position changes with the cavity length change.
This work is supported by the Department of Energy BES-RENEW award number DE-SC0024611.
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Abstract Number: ANPA2024-N00088 Presenting Author: Dipendra Dahal Presenter's Affiliation: nan Title: Resonance peak position tuning in Fabry Perot Interferometer. Location: In-Person Presentation, Fayetteville Show/Hide Abstract Making use of Maxwell’s equation, we have derived the relation of transmission and reflectance of a multilayer system which was used to determine the transmission and reflection spectra of distributed Bragg reflectors made up of TiO2/MgF2. We further evaluate the transmission and reflection spectra of the Fabry Perot interferometer constructed from the TiO2/MgF2, this DBR is later used to obtain the graphical representation of the spectra. In addition to this, we further analyze the resonant peak position variation with respect to the cavity length. We discuss the theory and the calculations to apply them in the optoelectronic devices.
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Abstract Number: ANPA2024-N000143 Presenting Author: Ganapathi Subramania (Invited) Presenter's Affiliation: Sandia National Laboratories Title: Light manipulation with nanostructures Location: Virtual Presentation Show/Hide Abstract Photonic crystals, metamaterials and metasurfaces are nanophotonic structures that demonstrate novel avenues of light manipulation at wavelength and subwavelength scales enabling phenomena like high Purcell factors, topological behavior, anomalous refraction or flat lensing. This talk will discuss some selected work performed at Sandia on some of these topics at Sandia involving various semiconductors (III-V, III-nitrides, Si) and dielectrics (e.g., TiO2)across infrared to visible wavelengths.
Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. The views expressed in the article do not necessarily represent the views of the U.S. Department of Energy or the United States Government.
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Abstract Number: ANPA2024-N000144 Presenting Author: Abdul Klam Khan Presenter's Affiliation: Amrit Campus, Tribhuvan University Title: Effect of Plasma-activated Water in the yield of oyster mushroom Location: Virtual Presentation Show/Hide Abstract In an effort to increase the productivity of oyster mushroom, the idea of plasma treatment employing gliding arc discharge in air at room temperature and atmospheric pressure is developed. This experiment uses plasma-activated water augmented by gliding arc discharge to monitored the budding and production of oyster mushroom. We look at the physio-chemical characteristics of plasma-activated water (PAW). When the treatment period of de-ionised water is increases from 0 minutes to 20 minutes, the activation of water, of gliding arc, pH value decreasing with rising electrical conductivity, oxidation reduction potential, total dissolved solids and concentrations of nitrate and nitrite. We have seen the 10 minutes treated mushroom production is 25% and 20 minutes treated mushroom production is 36% higher than untreated mushroom production. The time for the budding period for plasma-treated mushrooms was found to be faster 3 days than control. The budding and production parameter of oyster mushroom have been significantly impacted by plasma-activated water. Remarkably, when the 20 minute PAW is applied, seed budding is faster and production are higher.
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Abstract Number: ANPA2024-N000145 Presenting Author: N. Rama Devi Presenter's Affiliation: Tribhuvan University Title: Synthesis, structure, Stokes and anti‑Stokes visible luminescence of Tm3+–Yb3+ co‑doped Lu3Sc2Ga3O12 nanorods Location: Virtual Presentation Show/Hide Abstract Lu3Sc2Ga3O12 garnet nanorods co-doped with Tm3+ and Yb3+ optically active ions have been synthesized by Pechini sol–gel method, and their structural, morphological and luminescence properties have been explored. X-ray difraction pattern
confrmed that the synthesized Lu3Sc2Ga3O12 nanomaterials were crystallized in cubic garnet structure with crystallite size of 30 nm. Morphology of these powders confrmed the formation of rods with an average length of 8 μm and
diameter of 90 nm. The difuse refectance spectra were used to obtain partial energy-level structure of Tm3+ and Yb3+ ions in
Lu3Sc2Ga3O12 nanorods. Intense blue Stokes luminescence of Tm3+ ions at around 454 nm, under 360 nm ultraviolet excitation, as well as anti-Stokes luminescence at around 483 nm and co-operative luminescence at 490 nm, under near-infrared
980 nm excitation, have been measured. The intensity of these peaks increased with increasing of Yb3+ concentration up
to 5 mol% and then decreased due to energy transfer between optically active ions. In addition, luminescence at ~ 545 and
565 nm has been observed in the anti-Stokes spectra which is due to the energy transfer from Ln3+ ions to the impurities
such as Er3+ and Ho3+ ions. Laser pump power-dependent luminescence spectra confrmed that three photons were involved
to populate the 1G4 level in the upconversion mechanism. Luminescence decay curves have been measured for 1D2 level and have been found to be non-exponential with an average lifetime of 20 μs. The non-exponential nature of decay curves is
ascribed to energy transfer among Tm3+ ions through cross-relaxation processes. Colour co-ordinates of the samples excited at 980 nm lie in the blue–green region and also near to the white light region in the CIE diagram. All these results indicate
that the present garnets could be a promising optically active material for the solid-state display devices.
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