Message from Division Chair
Atomic, Molecular, Optical, and Plasma (AMOP) Physics fundamentally studies light, matter, and interactions at atomic and molecular levels. It deals with protons, electrons, ions, and their collective behavior in response to electric and magnetic fields. AMOP encompasses a broad area including but not limited to the following disciplines:
- Generation of light-source, ultrafast laser, and applications
- Light-induced emergent behavior in quantum materials
- Non-linear optics, biomedical optics and nano-optics
- Plasma physics – laboratory, space, and astrophysical
- The behavior of atoms in an ultracold, ground, and excited state
- Terahertz physics, metamaterials, and nanophotonic structures
- Precision measurement, quantum information, and sensing
- Plasma–matter interaction and applications
- Ultrafast Spectroscopy
The AMOP division was established from the outset of the first ANPA conference, aiming to bring together students and researchers – both from academia and industry to present and discuss their research, innovation, and technology related to AMOP physics, fostering knowledge exchange and collaboration within the community and across the globe. We cordially invite researchers, scientists, and experts from various disciplines for abstract submission and look forward to seeing your exciting science during the conference.
Important Links
View Presentation Schedule
Conference Timeline
Invited Speaker
Topologies in light & magnets: probing spin textures and optical phase structures
Symmetry breakings are ubiquitous in nature and can lead to the formation of various topological states and excitations, such as those in ferromagnetism, molecular chirality, optical activity, and vortex beams carrying orbital angular momentum (OAM). In the first part of my talk, I will show how a new coherent diffractive imaging technique, called vector ptychographic tomography, which uses coherent extreme UV or soft x-ray beams, can probe chemically resolved nanostructures in semiconductor materials1 and spin textures in magnetic materials. This lensless computational imaging method provides 2D/3D vector imaging with a resolution of 5-10 nm2, leading to our direct observation of topological magnetic monopoles and their interactions3. Next, I will introduce topological states of light carrying OAM, which can be static, attosecond-to-femtosecond dynamic4, spin-orbit coupled5, or spatiotemporally coupled6,7 (a subset of space-time optics family8). OAM of light can span the infrared to extreme UV spectra when up-converted and controlled through a laser-driven high-order harmonic generation process4,5 (the process recognized by the 2023 Nobel Prize in Physics). OAM of light and the new space-time optics promise novel and under-exploited applications in communications, sensing, imaging, and controlling topological spin textures in the near future.
References:
[1] Science Advances 7, 9667 (2021)
[2] Science Advances 5, eaax3009 (2019)
[3] Nature Nanotechnology 18, 227 (2023)
[4] Science 364, eaaw9486 (2019)
[5] Nature Photonics 13, 123 (2018)
[6] Nature Photonics 15, 608 (2021)
[7] ACS Photonics 9, 2802 (2022)
[8] Journal of Optics 25, 093001 (2023)
Division Schedule
Please look below for detailed schedule.
|
Date/Time: |
Abstract Number: ANPA2025-N00014 Presenting Author: Chen-Ting Liao (Invited) Co-Authors: nan Presenter's Affiliation: Indiana University (IU) Bloomington, Bloomington, IN US Title: Topologies in light & magnets: probing spin textures and optical phase structures Location: Virtual Presentation Show/Hide Abstract Symmetry breakings are ubiquitous in nature and can lead to the formation of various topological states and excitations, such as those in ferromagnetism, molecular chirality, optical activity, and vortex beams carrying orbital angular momentum (OAM). In the first part of my talk, I will show how a new coherent diffractive imaging technique, called vector ptychographic tomography, which uses coherent extreme UV or soft x-ray beams, can probe chemically resolved nanostructures in semiconductor materials1 and spin textures in magnetic materials. This lensless computational imaging method provides 2D/3D vector imaging with a resolution of 5-10 nm2, leading to our direct observation of topological magnetic monopoles and their interactions3. Next, I will introduce topological states of light carrying OAM, which can be static, attosecond-to-femtosecond dynamic4, spin-orbit coupled5, or spatiotemporally coupled6,7 (a subset of space-time optics family8). OAM of light can span the infrared to extreme UV spectra when up-converted and controlled through a laser-driven high-order harmonic generation process4,5 (the process recognized by the 2023 Nobel Prize in Physics). OAM of light and the new space-time optics promise novel and under-exploited applications in communications, sensing, imaging, and controlling topological spin textures in the near future.
|
||||||
|
Date/Time: |
Abstract Number: ANPA2025-N00018 Presenting Author: Tikaram Neupane Co-Authors: Uma Poudyal Presenter's Affiliation: The University of North Carolina at Pembroke, Pembroke, NC 28372 Title: Spatial Self-Phase Modulation in Tungsten and Molybdenum Disulfide Atomic Layers Location: Virtual Presentation Show/Hide Abstract The study on the polarity and magnitude of the atomic layer's nonlinear refraction (NLR) coefficient is of great interest for optoelectronic applications. It is studied through the laser-induced spatial self-phase modulation (SSPM) of an optical field, revealing the nonlinear refraction coefficients. SSPM of the optical field in liquid suspensions of tungsten and molybdenum disulfide atomic layers produced multiple concentric diffraction rings in the far field due to the laser-induced intensity-dependent refractive index in the materials. These rings arise from the coherent superposition of transverse wave vectors. The nonlinear refractive index of the materials was estimated by analyzing the number of rings as a function of incident intensity. Additionally, the polarity of the nonlinear refraction was inferred from the symmetry of the diffraction patterns. The temporal behavior of the diffraction rings revealed distinct phases: initial spatial alignment of nanoflakes upon excitation, a peak number of rings at intermediate times, and thermal distortion—particularly in the upper vertical rings—during prolonged laser exposure. This vertical asymmetry in the diffraction pattern indicates phase distortion caused by the distortion of the coherent superposition of transverse wave vectors due to the localized thermal vortex of the atomic layer in the aqueous solution that offers novel platforms of thermal metrology based on the localized optical nonlinearity and temperature-sensitive all-optical switching. Furthermore, the ratio of the distortion angle to the half-cone angle of the SSPM pattern, plotted against input intensity, demonstrated the variation of the nonlinear refractive index under thermal effects. Acknowledgment: This work was supported by the Department of Chemistry and Physics at the UNCP.
|
||||||
|
Date/Time: |
Abstract Number: ANPA2025-N00019 Presenting Author: Suresh Gnawali Co-Authors: Vadym Apalkov Presenter's Affiliation: Baylor University Title: High-order harmonics generated in graphene quantum dots with vacancy defects Location: Virtual Presentation Show/Hide Abstract We study theoretically the generation of high-order harmonics in hexagonal and triangular graphene quantum dots (QDs) with vacancy defects in the field of an optical pulse. For intrinsic QDs, some high-order harmonics are suppressed due to symmetry of the systems. Then, the main effect of vacancies is the breaking of the QD’s symmetry and the enhancement of the corresponding harmonics. For a hexagonal QD, for an intrinsic case, even-order harmonics are suppressed for a linearly and circularly polarized pulses, while 3m-order (m is an integer) harmonics are also suppressed for a circularly polarized pulse, with a monovacancy, all high-order harmonics are strongly enhanced. Suppression and enhancement of high-order harmonics for triangular QDs with armchair edges is similar to the case of hexagonal QDs. For triangular QDs with zigzag edges, all high-order harmonics are visible in the intrinsic case, while the presence of a monovacancy enhances the intensities of all harmonics.
|
||||||
|
Date/Time: |
Abstract Number: ANPA2025-N00015 Presenting Author: Bablu Kant Thakur Co-Authors: Dr. Lekha Nath Mishra; Dr. Rajendra Shrestha; Arun Kumar Shah; Ram Lal Shah Presenter's Affiliation: Tribhuvan University - Trichandra Multiple Campus, Physics Title: Impact of APPJ on Swiss Chard Seed Location: In-Person Presentation, CDP Show/Hide Abstract The atmospheric pressure plasma jet is generated with quartz glass tube of external diameter 5 mm and internal diameter 3 mm. Argon gas is used as working gas. The plasma jet has been characterized with measurement of electron density and electron temperature by electrical and optical method. The plasma jet is exposed on Swiss Chard seed. The germination percentage of Swiss Chard was found to be increased.
|
||||||
|
Date/Time: |
Abstract Number: ANPA2025-N00020 Presenting Author: Saddam Husian Dhobi Co-Authors: Saddam Husain Dhobi; Surendra Hangsarumba; Raman Kumar Kamat;, Jeevan Jyoti Nakarmi; Kishori Yadav; Suresh Prasad Gupta; Ajay kumar Jha Presenter's Affiliation: Tribhuvan University Title: Thermal and Laser Field Driven PEMFC as Electron and Proton Sensing with Hydrogen Sources Location: In-Person Presentation, CDP Show/Hide Abstract This study explores a thermal and laser field-driven Proton Exchange Membrane Fuel Cell (PEMFC), focusing on surface scattering effects that lead to the formation of electrons and protons from hydrogen molecules. The system functions as a dual electron-proton sensor, enabling the detection of hydrogen sources through charge carrier interactions at the PEMFC surface. The primary objective is to examine the relationship between the differential cross-section (DCS) and the output voltage of the PEMFC, both theoretically and experimentally. A theoretical model was first developed using the thermal Volkov wave function, Kroll-Watson approximation, Bessel function and the first-Born approximation to analyze DCS behavior with respect to temperature. The results suggest that DCS increases with temperature, indicating greater electron separation and a corresponding decrease in the electric field and output voltage. To validate this model, a PEMFC prototype was designed and fabricated. Experimental findings revealed that applying a laser field increased voltage, while thermal input alone reduced it. However, the combined application of laser and thermal fields resulted in maximum voltage output. These observations suggest that higher voltage corresponds to stronger electric fields and closer electron interaction implying lower DCS while reduced voltage reflects weaker fields and dispersed electron interactions at the PEMFC surface.
|
||||||
|
Date/Time: |
Abstract Number: ANPA2025-N00021 Presenting Author: Santosh Dhungana Co-Authors: Raju Khanal; Hom Bahadur Baniya Presenter's Affiliation: Tribhuvan Univesity Title: Physical and Chemical Profiling of Plasma-Activated Water Under Varying Treatment Conditions and Its Application in Plant Growth Location: In-Person Presentation, CDP Show/Hide Abstract Gliding arc discharge (GAD) system 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 the field of agriculture, it can be used directly by treating seed and indirectly by preparing plasma activated water (PAW). Due to the presence of reactive oxygen and nitrogen species (RONS), it is considered a green fertilizer for seed germination and plant growth. In our work, GAD system was used to produce PAW and its physiochemical properties are examined under varying treatment conditions including treatment time, air flow rate, applied voltage and water volume. A significant change in physical (pH, electric conductivity (EC), oxidation reduction potential (ORP), total dissolved solid (TDS), salt, etc.) and chemical (concentration of nitrate, nitrite and hydrogen peroxide) properties of water are observed at different treatment conditions. Finally, the PAW is utilized to irrigate the newly germinated seedling of red cherry pepper chili (Akabare Khursani) in order to study its on growth.
|
||||||
|
Date/Time: |
Abstract Number: ANPA2025-N00023 Presenting Author: Saroj Pandeya Co-Authors: Suresh Basnet; Raju Khanal Presenter's Affiliation: Tribhuvan University Title: Oblique Propagation of Ion-Acoustic Solitary Waves in 3D3V Magnetized Quantum Plasma with Anisotropic Electron and Ion Pressures. Location: In-Person Presentation, CDP Show/Hide Abstract Quantum ion-acoustic solitary waves (QIASWs) are studied in dense astrophysical environments, and collisional laboratory plasmas employing a quantum hydrodynamic model with anisotropic temperatures, constant magnetic field along z-axis, and the Bohm potential gradient to examine the formation and evolution of QIASWs. Anisotropic equation of state with degeneracy (relativistic and non-relativistic) for white dwarf plasma, and double adiabatic approximation for laboratory collisional plasma are applied in polytropic form in two-fluid momentum transport equations. Effect of weak magnetization on solitary vortical structures is also studied in fermi plasma. Hydrodynamic approximation is ensured for each plasma by satisfying conditions involving the mean free path, quantum plasma Debye length, and characteristic plasma length and time scales. Using the multiscale reductive perturbation technique with distinct ion, electron and potential expansion parameter, we derived the Korteweg–de Vries (KdV), dissipative KdV, and modified KdV (mKdV) equations, balancing of nonlinearity and dispersive effects, and compared with previous studies. The phase velocity of a solitary wave was found to be decreasing with obliqueness, independent of stretching and perturbation parameters, but depended on equilibrium pressures along the direction of the magnetic field, equilibrium density of species, and dust charge. The effect of viscous forces contributes to the damping of solitary waves leading to continuously decreased amplitude and increased width along stretched spacetime coordinates in laboratory plasma. Increasing magnetic field was found to increase amplitude and compress width of refractive as well as compressive solitary structures in each plasma at different cases i.e. T_(∥ ) >T_⊥, T_(∥ )=T_⊥, and T_(∥ ) |
||||||
|
Date/Time: |
Abstract Number: ANPA2025-N00024 Presenting Author: Ramesh Khanal Co-Authors: Dr. Suresh Basnet; Prof. Raju Khanal Presenter's Affiliation: Student Title: Magnetized Plasma-Wall Interaction Mechanism in the Presence of Secondary Electron Emission Relevant to Fusion Devices Location: In-Person Presentation, CDP Show/Hide Abstract Understanding plasma-wall interactions is crucial for improving the performance, lifetime, and
stability of magnetically confined fusion devices. This study employs a kinetic trajectory
simulation method to investigate the plasma-wall interaction (where the surfaces are tungsten,
carbon, and molybdenum) in the presence of secondary electron emission, energy-dependent
sputtering effects, self-consistent electric fields, and oblique magnetic fields. The model is
constrained to a 1D3V, time-independent, collisionless framework. Particle distribution functions
at the injection plane are assumed to be cut-off Maxwellians. Ion distribution functions are
obtained by tracing exact trajectories in phase space, while electron and emitted electron
densities are analytically obtained. Key plasma-wall transition conditions; quasineutrality,
sheath-edge singularity, continuity of macroscopic fluid parameters, and the Bohm sheath
criterion are satisfied, with a presheath-sheath coupling applied for smooth transition between
presheath-sheath boundary. The Bohm sheath condition is extended to multi-component plasmas
with cut-off distributions of emitted electrons. Simulations reveal that emitted electrons
substantially modify the potential profile, flattening the potential drop and introducing non-
monotonic structures. In oblique magnetic fields, the Bohm velocity for ions decreases with field
angle, reflecting stronger field-aligned motion requirements, while strong electron emission
lowers these velocity thresholds by weakening the sheath potential. Regarding material erosion,
tungsten shows the lowest sputtering yields than that of molybdenum, and carbon surfaces,
emphasizing the critical role of material selection in plasma-facing component design for fusion
devices.
|
||||||
|
Date/Time: |
Abstract Number: ANPA2025-N00025 Presenting Author: Abdul Klam Khan Co-Authors: nan Presenter's Affiliation: Central Department of Physics, Tribhuvan University Title: EFFECT OF PLASMA ACTIVATED WATER IN THE YIELD OF OYSTER MUSHROOM Location: In-Person Presentation, CDP Show/Hide Abstract In this study, plasma-activated water (PAW) produced using gliding arc discharge plasma was used to observe its effect on the budding and growth of oyster mushrooms. The activation of de-ionised water by plasma causes significant changes in the physical and chemical properties of PAW. With the increase in treatment time of the water, the pH of the water decreased, while the electrical conductivity, oxidation-reduction potential, total dissolved solids, and the levels of nitrate and nitrite increased. PAW showed a strong effect on the budding and production of oyster mushrooms. Notably, when 20-minute treated PAW was used, the seeds budded faster, and the production yield was higher. These results suggest that plasma-activated water can be an effective method to enhance the cultivation of oyster mushrooms.
|
||||||
|
Date/Time: |
Abstract Number: ANPA2025-N00026 Presenting Author: Samjhana Dahal Co-Authors: Roshan Chalise, Raju Khanal Presenter's Affiliation: Student (Tribhuvan University) Title: Germination and Seedling Growth Enhancement Of Timur Seed (Zanthoxylum armatum) By Using Cold Atmospheric Pressure Plasma Location: In-Person Presentation, CDP 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.
|
||||||
|
Date/Time: |
Abstract Number: ANPA2025-N00017 Presenting Author: Raman Kumar Kamat Co-Authors: Raman Kumar Kamat, Surendra Hangsarumba, Kishori Yadava, Suresh Prasad Gupta, Prakash M. Shrestha, Saddam Husain Dhobi Presenter's Affiliation: Department of Physics, Patan Multiple Campus, Tribhuvan University, Patan Dhoka, Lalitpur-44700, Nepal Title: Optical Characterization of Carbon Quantum Dots Under Laser and Magnetic Field Treatments Location: In-Person Presentation, CDP Show/Hide Abstract This study explores the influence of external treatments laser and magnetic field on the optical behavior of carbon quantum dots (CQDs) at varying concentrations. The approach aims to enhance understanding of how such treatments can modulate CQDs’ optical properties for advanced photonic and sensing applications. This study investigates the optical transmittance of CQDs at various concentrations (100%, 50%, 25%, and 12.5%) under different conditions, including laser and magnetic field treatments, all conducted at room temperature. CQDs were synthesized via a microwave-assisted method by mixing 0.2 g of thiourea and 0.4 g of citric acid, heated at 165 °C for 2 minutes. The heating product was dispersed in 40 mL of distilled water, followed by sonication and centrifugation. The optical properties were evaluated using a Theremino spectrometer, while CQDs confirmation was conducted by observing the fluorescence response under UV light after dropping into distilled water. The results demonstrated that the optical intensity was lowest at 100% concentration and gradually increases with dilution, reaching the lowest intensity at 12.5% diluted. For the 50% CQDs solution, samples were treated with a 100 mW laser and a 0.20 T magnetic field for 4 minutes. Compared to the untreated sample, the laser-treated CQDs showed increased intensity, whereas magnetic field treatment resulted in reduced intensity. Additionally, refractive index measurements using a rotating spectrometer revealed values of 1.340± 0.01 for the untreated 50% diluted sample, 1.350± 0.01 after laser treatment, and approximately 1.360 ± 0.01 after magnetic field treatment. These findings indicate that both treatments significantly influence the optical behavior and refractive index of CQDs.
|
||||||
|
Date/Time: |
Abstract Number: ANPA2025-N00016 Presenting Author: Bishnu Sedai Co-Authors: nan Presenter's Affiliation: Fairmont State University Title: Spectral Shift Functions for One-Dimensional Schrödinger Operators Location: In-Person Presentation, Fairmont Show/Hide Abstract In quantum mechanics and operator theory, the spectral shift function (SSF) measures how the spectrum of an operator changes under perturbations. For one-dimensional Schrödinger operators, the SSF provides information on scattering behavior, eigenvalue changes, and trace formulas. In this talk, we will present the SSF, elucidate its derivation from Krein's trace formula, and demonstrate its explicit computation through basic one-dimensional examples. We begin with a constant potential shift, where the entire spectrum rigidly translates, then explore delta and square-well potentials to understand localized spectral changes. The goal is to make this powerful analytical tool accessible to undergraduate researchers while illustrating its deep connections to quantum physics.
|
||||||
|
Date/Time: |
Abstract Number: ANPA2025-N00022 Presenting Author: Dipendra Khatri Co-Authors: Christopher Lantigua, Tran-Chau Truong, Chelsea Kincaid, Eric Van Stryland, and Michael Chini Presenter's Affiliation: University of Central Florida Title: Measurement of Real-Time Evolution of Vibrational Nonlinearity in Fused Silica Location: In-Person Presentation, Fairmont Show/Hide Abstract We present field-resolved measurements of vibrational nonlinearity in fused silica using sub-10 femtosecond pulses at 1 micron, generated via a two-stage hybrid compression system. These ultrashort pulses, derived from a Yb:KGW regenerative amplifier and spectrally broadened through gas-filled multi-pass cells and hollow-core fibers, enable probing of phonon dynamics on timescales shorter than the material's phonon coherence time.
To capture the real-time vibrational response, we employ the TIPTOE (tunnel ionization with perturbation for time-domain observation of the electric field) technique, utilizing a solar-blind AlGaN photodiode as both nonlinear medium and detector. This adaptation allows us to observe the nonlinear vibrational dynamics driven by the ultrashort pulses. Comparing signals with and without the sample isolates the material-specific response, revealing coherent phonon oscillations in fused silica.
By extracting the electric field envelopes and performing Fourier analysis, we obtain the Raman gain spectrum of fused silica, which shows strong agreement with theoretical predictions based on Stolen’s model. These results provide direct insight into the vibrational nonlinearities of fused silica, a material widely used in ultrafast optics but with incompletely understood phonon dynamics.
Our work offers a valuable method for investigating ultrafast vibrational phenomena in dielectric materials and contributes to the broader understanding of nonlinear optical processes relevant for applications in ultrafast switching, nonlinear fiber optics, and photonic device development.
|
||||||