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Post-Graduate Research
RESEARCH INTERESTS
➢ Thermomagnetic Cooling
➢ Semimetallic Thermoelectrics
➢ 2D Thermoelectrics
RESEARCH GROUP
Energy Science Nanotechnology and and Imagination Lab, UVA
Lab Head: Dr. Mona Zebarjadi
Associate Professor
Dept of Electrical Engineering & Dept of Materials Science Engineering
University of Virginia.
Office: Thornton E-218 | Lab: Wilsdorf A011
351 McCormick Road, Charlottesville, VA
Publications
Md Sabbir Akhanda, Katherine A. Schlaak, Eleanor F. Scott, Md Nasim Afroj Taj, Sarah J. Watzman, Mona Zebarjadi; Thermomagnetic responses of semimetals. J. Appl. Phys. 28 June 2024; 135 (24): 240901. https://doi.org/10.1063/5.0192824
Undergraduate Research
RESEARCH INTERESTS
➢ Plasmonic Nanolaser
➢ Nanophotonics
➢ Optoelectronic Devices.
RESEARCH GROUP
Nanophotonics Research Group, BUET
Lab Head: Dr. Muhammad Anisuzzaman Talukder
Professor, Department of EEE, BUET
Director, RISE, BUET
Publications
Mahin Ahamed, Md. Nasim Afroj, Shadman Shahid, and Muhammad Anisuzzaman Talukder, "Wavelength selective beam-steering in a dual-mode multi-layer plasmonic laser," Opt. Express 32, 19895-19909 (2024). https://doi.org/10.1364/OE.518705
RESEARCH BRIEF
'LASER' is an abbreviation for Light Amplification by Stimulated Emission of Radiation. This implies that a laser is a device capable of converting light into a focused, coherent, high-energy light beam. When the principle of lasers was first introduced by Einstein, much was not known about its implications, but it was evident that lasers had immense potential for future applications because of their amplifying characteristics.
In the field of nanoelectronics, manipulation of coherent radiation in nano-scale has upheld research criteria of nanophotonic devices and photonic ICs recently. Researchers are continuously overtaking difficulties in this field to carry out new and more innovative uses of the tool, nanolaser.
Our Nanophotonics Research Group has been very active in the field of Plasmonic Nanolasers for the past few years. We have already published some noteworthy research works, which have already been published in prominent journals, and more research are already being conducted currently by postgraduate and undergraduate students under the supervision of Dr. Muhammad Anisuzzaman Talukder The associated images to this post highlight two of the most recent publications in this field from our group.
1. Ahmed, Z.; Talukder, M. A. An Efficient and Directional Optical Tamm State Assisted Plasmonic Nanolaser with Broad Tuning Range. J Phys Commun 2018, 2 (4), 045016. https://doi.org/10.1088/2399-6528/aab7e4.
In this paper, a nanolaser design for near-infrared narrow-beam emission at room temperature is proposed. The issues of bidirectional emission, multiple far-field spatial states of conventional plasmonic lasers are overcome in this laser design. The structure is shown in the 2nd picture. This planar structure excites Tamm states (Kaliteevski, 2007) at the metal-gain interface, which stimulates lasing emission from the gain medium. Also, extraordinary transmission (Ebbesen, 1998) via metal nanohole array (NHA) is amplified by the 1D Photonic crystal (Treshin, 2013).
2. Azad, Z.; Islam, Md. S.; Talukder, M. A. Mode-Resolved Analysis of a Planar Multi-Layer Plasmonic Nanolaser. Opt Commun 2021, 482, 126614. https://doi.org/10.1016/j.optcom.2020.126614.
This paper explains the theoretical and physical basis of the action of the aforementioned plasmonic nanolaser. The modes/states of the structure are decomposed and analyzed to obtain to determine the exact role of plasmonic and photonic modes (if any) in the structure. The 3rd figure shows the dispersion relation of the mentioned structure step by step.
Currently, Nasim and Mahin are working on Plasmonic nano-lasers. They are studying Surface Plasmons, DBR & nano-cavity to understand the mechanisms of Plasmonic Nanolaser design and its properties. They are using FDTD (Finite-difference Time-domain) method to perform these analyses. The main focus of their thesis is, "Multi-mode Plasmonic Nanolaser With Beam Steering For Multi-sensing" as a continuation of the foregoing research of previous years thesis work titled, "An Investigation into Dual-mode Lasing Response in Planar Multi-layer Plasmonic Laser System" (More Details)
B.Sc. Thesis BRIEF
Wavelength-dependent Beam-steered Dual-mode Multi-layer Plasmonic Lasers
Author: Md. Nasim Afroj Taj & Mahin Ahamed
Supervisor: Dr. Muhammad Anisuzzaman Talukder
Abstract: Ever since their invention, lasers have been very useful in various scenarios and sectors of science. Specially miniature lasers emitting multiple modes have numerous applications. This is quite a new research interest that has gained publicity very recently because it has now opened ample scopes for advancement. Tamm states, the plasmonic resonance at the metal and 1D PhC (Photonic Crystal) junction, have been utilized to produce significant plasmonic lasers. In the previous thesis done by our seniors, the generation of dual-mode nanolaser was explored. But they overlapped in the spatial domain. In this thesis, we explored methods of separating the two modes in the spatial domain. We took several approaches for this purpose. At first, we mainly focused on transmission diffraction gratings. We attached various diffraction gratings to our laser and observed the response. We used CAT (Critical Angle transmission) and Blazed Grating but in both cases, the separation of two different wavelengths were not in the acceptable range. So, we explored some other designs.
In one of the strategies we tried, we used rectangular gradient metasurfaces, and we modified their parameters by analyzing how much radiation was emitted from them. Based on our observations, we then finalized our design with the optimal values that separated the two prominent wavelengths in 90°, which meets our target.
Finally, we looked at another gradient metasurface, this time using cylindrical slabs as the building blocks. We have efficiently separated two modes by 43° and by tuning different parameters, the separation can be increased up to 89° as well as multiple beams can be generated, hence manual beam steering has been achieved. Both of our ideas have a high emission output with a very narrow linewidth, and clarity, and also have a significant amount of tunability potential in the future.
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