ORCID Profile
0000-0001-9776-790X
Current Organisations
First Capital University Bangladesh
,
Singapore university of technology and design
,
Institute of Materials Research and Engineering
,
First Capital University of Bangladesh, Chuadanga.
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Publications
Nanoscale mapping of optically inaccessible bound-states-in-the-continuum
Publisher: Springer Science and Business Media LLC
Date: 20-01-2022
DOI: 10.1038/S41377-021-00707-2
Abstract: Bound-states-in-the-continuum (BIC) is an emerging concept in nanophotonics with potential impact in applications, such as hyperspectral imaging, mirror-less lasing, and nonlinear harmonic generation. As true BIC modes are non-radiative, they cannot be excited by using propagating light to investigate their optical characteristics. In this paper, for the 1st time, we map out the strong near-field localization of the true BIC resonance on arrays of silicon nanoantennas, via electron energy loss spectroscopy with a sub-1-nm electron beam. By systematically breaking the designed antenna symmetry, emissive quasi-BIC resonances become visible. This gives a unique experimental tool to determine the coherent interaction length, which we show to require at least six neighboring antenna elements. More importantly, we demonstrate that quasi-BIC resonances are able to enhance localized light emission via the Purcell effect by at least 60 times, as compared to unpatterned silicon. This work is expected to enable practical applications of designed, ultra-compact BIC antennas such as for the controlled, localized excitation of quantum emitters.
Hierarchical Colorful Structures by Three-Dimensional Printing of Inverse Opals
Publisher: American Chemical Society (ACS)
Date: 18-10-2021
Stiff Shape Memory Polymers for High-Resolution Reconfigurable Nanophotonics.
Publisher: American Chemical Society (ACS)
Date: 10-11-2022
DOI: 10.1021/ACS.NANOLETT.2C03007
Abstract: Reconfigurable metamaterials require constituent nanostructures to demonstrate switching of shapes with external stimuli. Yet, a longstanding challenge is in overcoming stiction caused by van der Waals forces in the deformed configuration, which impedes shape recovery. Here, we introduce stiff shape memory polymers. This designer material has a storage modulus of ∼5.2 GPa at room temperature and ∼90 MPa in the rubbery state at 150 °C, 1 order of magnitude higher than those in previous reports. Nanopillars with diameters of ∼400 nm and an aspect ratio as high as ∼10 were printed by two-photon lithography. Experimentally, we observe shape recovery as collapsed and touching structures overcome stiction to stand back up. We develop a theoretical model to explain the recoverability of these sub-micrometer structures. Reconfigurable structural color prints with a resolution of 21150 dots per inch and holograms are demonstrated, indicating potential applications of the stiff shape memory polymers in high-resolution reconfigurable nanophotonics.
Two‐Photon Polymerization Lithography for Optics and Photonics: Fundamentals, Materials, Technologies, and Applications
Publisher: Wiley
Date: 22-03-2023
Abstract: The rapid development of additive manufacturing has fueled a revolution in various research fields and industrial applications. Among the myriad of advanced 3D printing techniques, two‐photon polymerization lithography (TPL) uniquely offers a significant advantage in nanoscale print resolution, and has been widely employed in erse fields, for ex le, life sciences, materials sciences, mechanics, and microfluidics. More recently, by virtue of the optical transparency of most of the resins used, TPL is finding new applications in optics and photonics, with nanometer to millimeter feature dimensions. It enables the minimization of optical elements and systems, and exploration of light‐matter interactions with new degrees of freedom, never possible before. To review the recent progress in the TPL related optical research, it starts with the fundamentals of TPL and material formulation, then discusses novel fabrication methods, and a wide range of optical applications. These applications notably include diffractive, topological, quantum, and color optics. With a panoramic view of the development, it is concluded with insights and perspectives of the future development of TPL and related potential optical applications.
Engineering Dynamic Structural Color Pixels at Microscales by Inhomogeneous Strain-Induced Localized Topographic Change
Publisher: American Chemical Society (ACS)
Date: 08-06-2023
3D Printing Mesoscale Optical Components with a Low-Cost Resin Printer Integrated with a Fiber-Optic Taper
Publisher: American Chemical Society (ACS)
Date: 26-05-2022
Dielectric multi-momentum meta-transformer in the visible
Publisher: Springer Science and Business Media LLC
Date: 21-10-2019
DOI: 10.1038/S41467-019-12637-0
Abstract: Metasurfaces as artificially nanostructured interfaces hold significant potential for multi-functionality, which may play a pivotal role in the next-generation compact nano-devices. The majority of multi-tasked metasurfaces encode or encrypt multi-information either into the carefully tailored metasurfaces or in pre-set complex incident beam arrays. Here, we propose and demonstrate a multi-momentum transformation metasurface (i.e., meta-transformer), by fully synergizing intrinsic properties of light, e.g., orbital angular momentum (OAM) and linear momentum (LM), with a fixed phase profile imparted by a metasurface. The OAM meta-transformer reconstructs different topologically charged beams into on-axis distinct patterns in the same plane. The LM meta-transformer converts red, green and blue illuminations to the on-axis images of “R”, “G” and “B” as well as vivid color holograms, respectively. Thanks to the infinite states of light-metasurface phase combinations, such ultra-compact meta-transformer has potential in information storage, nanophotonics, optical integration and optical encryption.
High-resolution light field prints by nanoscale 3D printing
Publisher: Springer Science and Business Media LLC
Date: 17-06-2021
DOI: 10.1038/S41467-021-23964-6
Abstract: A light field print (LFP) displays three-dimensional (3D) information to the naked-eye observer under ambient white light illumination. Changing perspectives of a 3D image are seen by the observer from varying angles. However, LFPs appear pixelated due to limited resolution and misalignment between their lenses and colour pixels. A promising solution to create high-resolution LFPs is through the use of advanced nanofabrication techniques. Here, we use two-photon polymerization lithography as a one-step nanoscale 3D printer to directly fabricate LFPs out of transparent resin. This approach produces simultaneously high spatial resolution (29–45 µm) and high angular resolution (~1.6°) images with smooth motion parallax across 15 × 15 views. Notably, the smallest colour pixel consists of only a single nanopillar (~300 nm diameter). Our LFP signifies a step towards hyper-realistic 3D images that can be applied in print media and security tags for high-value goods.
Structural multi-colour invisible inks with submicron 4D printing of shape memory polymers
Publisher: Springer Science and Business Media LLC
Date: 04-01-2021
DOI: 10.1038/S41467-020-20300-2
Abstract: Four-dimensional (4D) printing of shape memory polymer (SMP) imparts time responsive properties to 3D structures. Here, we explore 4D printing of a SMP in the submicron length scale, extending its applications to nanophononics. We report a new SMP photoresist based on Vero Clear achieving print features at a resolution of ~300 nm half pitch using two-photon polymerization lithography (TPL). Prints consisting of grids with size-tunable multi-colours enabled the study of shape memory effects to achieve large visual shifts through nanoscale structure deformation. As the nanostructures are flattened, the colours and printed information become invisible. Remarkably, the shape memory effect recovers the original surface morphology of the nanostructures along with its structural colour within seconds of heating above its glass transition temperature. The high-resolution printing and excellent reversibility in both microtopography and optical properties promises a platform for temperature-sensitive labels, information hiding for anti-counterfeiting, and tunable photonic devices.
Toward Near-Perfect Diffractive Optical Elements via Nanoscale 3D Printing
Publisher: American Chemical Society (ACS)
Date: 20-07-2020
Modifications of Traditional Formulas to Estimate and Project Dependency Ratios and Their Implications in a Developing Country, Bangladesh
Publisher: Springer Science and Business Media LLC
Date: 11-05-2022
Reconfiguring Colors of Single Relief Structures by Directional Stretching.
Publisher: Wiley
Date: 26-12-2022
Abstract: Color changes can be achieved by straining photonic crystals or gratings embedded in stretchable materials. However, the multiple repeat units and the need for a volumetric assembly of nanostructures limit the density of information content. Inspired by surface reliefs on oracle bones and music records as a means of information archival, here, surface-relief elastomers are endowed with multiple sets of information that are accessible by mechanical straining along in-plane axes. Distinct from Bragg diffraction effects from periodic structures, trenches that generate color due to variations in trench depth, enabling in idual trench segments to support a single color, are reported. Using 3D printed cuboids, trenches of varying geometric parameters are replicated in elastomers. These parameters determine the initial color (or lack thereof), the response to capillary forces, and the appearance when strained along or across the trenches. Strain induces modulation in trench depth or the opening and closure of a trench, resulting in surface reliefs with up to six distinct states, and an initially featureless surface that reveals two distinct images when stretched along different axes. The highly reversible structural colors are promising in optical data archival, anti-counterfeiting, and strain-sensing applications.
High-Order Photonic Cavity Modes Enabled 3D Structural Colors
Publisher: American Chemical Society (ACS)
Date: 09-05-2022
Abstract: It remains a challenge to directly print arbitrary three-dimensional shapes that exhibit structural colors at the micrometer scale. Woodpile photonic crystals (WPCs) fabricated
Applying Machine Learning to the Optics of Dielectric Nanoblobs
Publisher: Wiley
Date: 05-11-2020
Knowledge, attitudes and practices of COVID-19 in rural Bangladesh: a cross-sectional study
Publisher: BMJ
Date: 02-2023
DOI: 10.1136/BMJOPEN-2022-064754
Abstract: Understanding the knowledge, attitudes and practices (KAP) of COVID-19 within distinct populations may aid further public health messaging. This study’s aims were to explore KAP towards COVID-19 in rural Bangladesh and identify any potential links to sociodemographics, existing clinical conditions and sources of information. Cross-sectional community-based study. Participants were recruited from 18 villages using multistage cluster random s ling. Data were collected through face-to-face interviews, from June to November 2021, using a structured questionnaire. Data included sociodemographics, clinical conditions, sources of information and KAP of COVID-19 questions. Χ 2 test, multiple logistic regression and correlation analyses were performed. A total of 1603 participants were included with mean ages of 42.3±14.2 years, ranging from 18 to 60 years. Of these, 51% were male, 42.2% had secondary education and 45% had comorbidities. Television was the main source of COVID-19 information (55.8%). The overall correct response rate of KAP questions was 90%, 78% and 59%, respectively. In stepwise multiple logistic regression, good knowledge was associated with higher education (adjusted OR (AOR): 4.61, 95% CI: 2.40 to 8.85, p .001), employment, high body mass index (overweight and obese) and trust in the sources of information. Being female (AOR: 1.48, 95% CI: 1.19 to 1.85, p .001), having depression (AOR: 1.80, 95% CI: 1.34 to 2.43, p .001), being a past smoker and sources of information (family members/friends/relatives/neighbours) were associated with positive attitudes. Good practices were associated with older age (AOR: 1.52, 95% CI: 1.10 to 2.11, p=0.01), higher education (AOR: 2.78, 95% CI: 1.58 to 4.89, p .001) and having anxiety, while current smokers and fully vaccinated people were less likely to be engaged in good practices. Positive significant correlations between domains of KAP were observed as well as between past vaccination KAP and COVID-19 KAP. This study uncovered gaps in understanding and practices, and identified targeted intervention especially for young and less educated people using mass media to promote updated knowledge regarding COVID-19 and the efficacy of preventive practices.
Evaluation of COVID-19 vaccine acceptance and uptake in rural Bangladesh: a cross-sectional study
Publisher: BMJ
Date: 12-2022
DOI: 10.1136/BMJOPEN-2022-064468
Abstract: The objective of this study was to evaluate the acceptance and uptake of COVID-19 vaccines in rural Bangladesh. This was a cross-sectional study conducted between June and November 2021. This study was conducted in rural Bangladesh. People older than 18 years of age, not pregnant and no history of surgery for the last 3 months were eligible to participate. The primary outcomes were proportions of COVID-19 vaccine acceptance and roll-out participation among the rural population. The secondary outcome was identification of correlates which contributed to COVID-19 vaccine acceptance and roll-out participation. Χ 2 tests and multivariable logistic regression analyses were performed to identify relevant correlates such as sociodemographic factors, clinical conditions and COVID-19-related factors. A total of 1603 participants were enrolled. The overall COVID-19 vaccine acceptance was very high (1521/1601, 95%), and half of the participants received at least one dose of the COVID-19 vaccine. Majority of participants wanted to keep others safe (89%) and agreed to the benefits of COVID-19 vaccines (88%). To fulfil the requirement of online registration for the vaccine at the time, 62% of participants had to visit an internet café and only 31% downloaded the app. Over half (54%) of participants were unaware of countries they knew and trust to produce the COVID-19 vaccine. Increased age, being housewives, underweight and undergraduate education level were associated with vaccine acceptance, while being female, increased age and being overweight/obese were associated with vaccine uptake. Trust in the health department and practical knowledge regarding COVID-19 vaccines were positively associated with both vaccine acceptance and uptake. This study found a very high COVID-19 vaccine acceptance in rural Bangladesh. Policymakers should support interventions aimed at increasing vaccine and general health literacy and ensure ongoing vaccine supply and improvement of infrastructure in rural areas.
Noninterleaved Metasurface for (2
Publisher: American Chemical Society (ACS)
Date: 06-12-2018
DOI: 10.1021/ACS.NANOLETT.8B04246
Abstract: Nanostructured metasurfaces demonstrate extraordinary capabilities to control light at the subwavelength scale, emerging as key optical components to physical realization of multitasked devices. Progress in multitasked metasurfaces has been witnessed in making a single metasurface multitasked by mainly resorting to extra spatial freedom, for ex le, interleaved subarrays, different angles. However, it imposes a challenge of suppressing the cross-talk among multiwavelength without the help of extra spatial freedom. Here, we introduce an entirely novel strategy of multitasked metasurfaces with noninterleaved single-size Si nanobrick arrays and minimalist spatial freedom demonstrating massive information on 6-bit encoded color holograms. The interference between electric dipole and magnetic dipole in in idual Si nanobricks with in-plane orientation enables manipulating six bases of incident photons simultaneously to reconstructed 6-bit wavelength- and spin-dependent multicolor images. Those massively reconstructed images can be distinguished by pattern recognition. It opens an alternative route for integrated optics, data encoding, security encryption, and information engineering.
Optical Fireworks Based on Multifocal Three-Dimensional Color Prints
Publisher: American Chemical Society (ACS)
Date: 21-05-2021
3D printed fiber sockets for plug and play micro-optics
Publisher: IOP Publishing
Date: 18-11-2020
Abstract: Integrating micro-optical components at the end facet of an optical fiber enables compact optics to shape the output beam (e.g. collimating, focusing, and coupling to free space elements or photonic integrated circuits). However, the scalability of this approach is a longstanding challenge as these components must be aligned onto in idual fiber facets. In this paper, we propose a socket that enables easy slotting of fibers, self-alignment, and coupling onto micro-optical components. This integrated socket can be detached from the substrate upon fiber insertion to create a stand-alone optical system. Fabrication is done using nanoscale 3D printing via two-photon polymerization lithography onto glass substrates, which allows multiple sockets to be patterned in a single print. We investigated variations in socket design and evaluated the performance of optical elements for telecom wavelengths. We obtained an alignment accuracy of ∼3.5 µ m. These socket designs can be customized for high efficiency chip to fiber coupling and extended to other spectral ranges for free-form optics.
Reversible Tuning of Mie Resonances in the Visible Spectrum
Publisher: American Chemical Society (ACS)
Date: 09-12-2021
Abstract: Dielectric optical nanoantennas are promising as fundamental building blocks in next generation color displays, metasurface holograms, and wavefront shaping optical devices. Due to the high refractive index of the nanoantenna material, they support geometry-dependent Mie resonances in the visible spectrum. Although phase change materials, such as the germanium-antimony-tellurium alloys, and post-transition metal oxides, such as ITO, have been used to tune antennas in the near-infrared spectrum, reversibly tuning the response of dielectric antennas in the visible spectrum remains challenging. In this paper, we designed and experimentally demonstrated dielectric nanodisc arrays exhibiting reversible tunability of Mie resonances in the visible spectrum. We achieved tunability by exploiting phase transitions in Sb
Off‐Axis Holography with Uniform Illumination via 3D Printed Diffractive Optical Elements
Publisher: Wiley
Date: 16-04-2019
Coloured vortex beams with incoherent white light illumination
Publisher: Springer Science and Business Media LLC
Date: 13-02-2023
Full Geometric Control of Hidden Color Information in Diffraction Gratings under Angled White Light Illumination.
Publisher: American Chemical Society (ACS)
Date: 13-10-2022
DOI: 10.1021/ACS.NANOLETT.2C02741
Abstract: Under white light illumination, gratings produce an angular distribution of wavelengths dependent on the diffraction order and geometric parameters. However, previous studies of gratings are limited to at least one geometric parameter (height, periodicity, orientation, angle of incidence) kept constant. Here, we vary all geometric parameters in the gratings using a versatile nanofabrication technique, two-photon polymerization lithography, to encode hidden color information through two design approaches. The first approach hides color information by decoupling the effects of grating height and periodicity under normal and oblique incidence. The second approach hides multiple sets of color information by arranging gratings in sectors around semicircular pixels. Different images are revealed with negligible crosstalk under oblique incidence and varying s le rotation angles. Our analysis shows that an angular separation of ≥10° between adjacent sectors is required to suppress crosstalk. This work has potential applications in information storage and security watermarks.
Full Color and Grayscale Painting with 3D Printed Low-Index Nanopillars
Publisher: American Chemical Society (ACS)
Date: 21-05-2021
Related Organisations
Massachusetts Institute Of Technology
Location: United States of America
First Capital University Of Bangladesh, Chuadanga.
Location: Bangladesh
Related Funding Activities
No related grants have been discovered for Md. Shariful Islam.