Laser sintering of silver-palladium ink for on-demand manufacturing of electronics for space applications Ellie Schlake, Sagar Kumar Verma, Nirmala Kandadai Scientific Reports, 2025 Printing technology has been designated as a useful method for in-space manufacturing (ISM) of electronics. A low-power payload method is necessary for sintering printed electronics in space. This work investigates laser sintering as a viable option for ISM. Specifically, we present our work on laser sintering silver-palladium (AgPd) on rigid alumina substrates for developing liquid conductivity sensors for water reclamation processes for low Earth orbit applications. The laser sintering parameters are laser wavelength, power, and scanning speed. The laser systems studied are continuous wave lasers at 445 nm, 808 nm, 915 nm, and 1064 nm, as well as a pulsed fs laser with a 1040 nm wavelength. The laser powers tested for each continuous wave laser are limited to 1–6 W, and 0.1–1 W for the fs laser, due to the laser systems’ power limitations. The scanning speed range tested is 0.1–1 mm/s. The 445 nm laser is determined to work most efficiently at sintering AgPd, resulting in a maximum increase in conductivity from 10 0 to 8.9 × 10 5 S/m. Comparatively, the maximum conductivities achieved by the 808 nm, 915 nm, 1064 nm, and fs lasers are 3.1 × 10 5 , 2.1 × 10 5 , 4.1 × 10 5 , and 1.1 × 10 1 S/m, respectively. Additionally, the results of all the laser systems are compared to those of furnace-sintered and thermally dried samples through their surface morphology and conductivity. The furnace-sintered and thermally dried AgPd resulted in maximum conductivities of 3.0 × 10 6 and 2.1 × 10 4 S/m, respectively. A data-driven model employing the transient heat transfer approach is developed using a licensed version of COMSOL Multiphysics 6.2. The simulation study supports the experimental laser sintering results, and the underlying physics is discussed.
Highly Sensitive Graphene-Assisted Large-Area Kapton-Based Flexible Surface Plasmon Resonance Biosensor for Enzymatic Glucose Detection Yadvendra Singh, Sagar Kumar Verma, Nirmala Kandadai, Harish Subbaraman ACS Applied Materials and Interfaces, 2025 The accurate measurement of glucose levels is crucial in various fields, including healthcare, pharmaceuticals, and food quality control. Given its importance in diagnosing and managing diabetes, monitoring pharmaceutical research, and ensuring food safety, there is a pressing need for glucose sensors. In the present work, we demonstrate an ultrathin, large-area, and highly cost-effective Kapton HN-based flexible-SPR (F-SPR) chip for glucose biomolecule sensing. Owing to its beneficial features, the F-SPR sensor chip overcomes the size, shape, and high-cost limitations of conventional SPR sensor chips. Large-area graphene, integrated together with the Kapton HN chips, was used to enhance the performance of the F-SPR chip. The sensors exhibit a maximum sensitivity of 4.0203 nm/mM using a single-layer graphene-based F-SPR chip within a glucose concentration of 0 to 10 mM. In addition, the detection limit of 89.55 μM was achieved with the proposed F-SPR chip in wavelength interrogation, which enables the label-free detection of trace amounts of glucose molecules. The repeatability, stability, and selectivity of the fabricated sensors were validated through systematically controlled experiments. This facile and cost-effective work provides a strategy for developing high-performance F-SPR sensor chips for small biomolecules, such as glucose, with several prospective applications in biomedicine and human health monitoring.
A graphene integrated Kapton based flexible and highly sensitive plasmonic sensor for uric acid sensing Sagar Kumar Verma, Yadvendra Singh, Harish Subbaraman, Nirmala Kandadai Sensors and Actuators Reports, 2025 One of the most common natural waste products from diets high in purines is uric acid that is commonly filtered by human kidneys. Excessive consumption and delayed excretion of uric acid can disrupt blood uric acid levels. Abnormal variations in the normal uric acid level, which is less than 6.8 mg/dL, can lead to several health issues, including kidney stones and gout, etc. Available biosensors for uric acid detection have various issues such as low sensitivity, poor selectivity, shorter shelf life, and poor repeatability. Kretschmann configuration-based plasmonic sensors are prominent candidates for resolving the issues but the available plasmonic chips are expensive because of the involvement of special glass substrates, such as SF11 and BK7. This work mainly focuses on the replacement of SF11 glass sensing chips with a low-cost and flexible Kapton chip that shares the same refractive index as SF11, without compromising the sensor’s sensitivity. Moreover, to enhance the sensitivity of the Kapton based plasmonic chips, they were integrated with 1 – 3 layers of graphene. These graphene-integrated flexible (GiF) plasmonic chips were functionalized with uricase enzyme to develop molecule selective uric acid sensors for point-of-care detection. The developed GiF chips achieved a maximum sensitivity of 0.0810nm/μM and 0.0171nm/μM in the range 0 to 200μM, and 200 to 1000μM, respectively, with a limit of detection of 11.450μM for uric acid. Controlled experiments were also performed to demonstrate the repeatability, stability, and selectivity of the sensors. GiF SPR chip presents its strong potential in developing portable and wearable biosensors.
Modeling the selective laser sintering of printed silver nanoparticle ink on a flexible substrate Sagar Verma, Ellie Schlake, Nirmala Kandadai Proceedings of SPIE the International Society for Optical Engineering, 2025 Silver nanoparticles (AgNPs) are widely used in printed electronics because of their high electrical conductivity. Unfortunately, “printing” does not provide a consolidated thin film of the desired material on the flexible substrate but simply delivers the ink to the substrate, leaving the material on the substrate in the form of wet nanoparticle (NP) agglomerates or clusters. A post-sintering or a post-annealing (thermal) step is mandatory to consolidate these NPs into a film for providing connectivity and realizing the desired film properties. Laser sintering is an attractive technology for creating the desired film due to its low power requirements and ability to selectively sinter parts of printed films. In continuous wave laser sintering, the optical radiation directly into the sample converts into a heat wave through a photo-thermal reaction. As a result, thermal penetration into the sample depends on the laser parameters, the thickness of the printed layer, the thermal conductivity of the ink, and the substrate. In this simulation work, we showcase how the thermal penetration for a focused laser signal on silver nanoparticle ink varies with substrate, scanning speed, ink thickness, spot size, and incident laser wavelength. The simulation was performed using finite element-based software COMSOL Multiphysics version 6.2. For the simulation, the laser source was considered a continuous wave laser with a laser wavelength of 445nm. The laser power was varied between 1W to 4W, and spot size was varied between 10μm to 150μm. The effect of different substrate materials was also studied.
The Effect of Mie-Scattering on Propagating Surface Plasmons Sagar Kumar Verma, Yadvendra Singh, Devyn Duryea, Harish Subbaraman, Nirmala Kandadai 2025 Conference on Lasers and Electro Optics CLEO 2025, 2025 The experimental study was done to observe the effect of the Mie-scattered light by LASiS synthesized TiO 2 nanoparticles on the propagating surface plasmon resonance (SPR) modes excited at metal-dielectric interface in prism based Kretschmann configuration.
The Effect of Mie-Scattering on Propagating Surface Plasmons Sagar Kumar Verma, Yadvendra Singh, Devyn Duryea, Harish Subbaraman, Nirmala Kandadai CLEO Science and Innovations Proceedings CLEO 2025, 2025 The experimental study was done to observe the effect of the Mie-scattered light by LASiS synthesized TiO 2 nanoparticles on the propagating surface plasmon resonance (SPR) modes excited at metal-dielectric interface in prism based Kretschmann configuration.
The Effect of Mie-Scattering on Propagating Surface Plasmons Sagar Kumar Verma, Yadvendra Singh, Devyn Duryea, Harish Subbaraman, Nirmala Kandadai CLEO Fundamental Science Proceedings CLEO 2025, 2025 The experimental study was done to observe the effect of the Mie-scattered light by LASiS synthesized TiO 2 nanoparticles on the propagating surface plasmon resonance (SPR) modes excited at metal-dielectric interface in prism based Kretschmann configuration.
Thermal Conductivity Measurement of a Thin Layer of The Single Crystals of SnO Using Time Domain Thermoreflectance Frontiers in Optics Fio 2024 in Proceedings Frontiers in Optics Laser Science 2024 Fio Ls Part of Frontiers in Optics Laser Science 2024, 2024
Thermal Conductivity Measurement of a Thin Layer of The Single Crystals of SnO Using Time Domain Thermoreflectance Laser Science Ls 2024 in Proceedings Frontiers in Optics Laser Science 2024 Fio Ls Part of Frontiers in Optics Laser Science 2024, 2024
Experimental Demonstration of Fano Resonance Based One Dimensional Plasmonic Metasurface Absorber for Refractive Index Sensing in NIR Regime Laser Science Ls 2023 in Proceedings Frontiers in Optics Laser Science 2023 Fio Ls Part of Frontiers in Optics Laser Science 2023, 2023
All metal 1D plasmonic metasurface broadband absorber for refractive index sensing in Mid-IR regime International Conference on Metamaterials Photonic Crystals and Plasmonics, 2023
Simulation of an EOT Based 1D-Plasmonic Metasurface Sensor for Absorptive Analytes Optics Infobase Conference Papers, 2022
Simulation of an EOT Based lD-Plasmonic Metasurface Sensor for Absorptive Analytes 2022 Conference on Lasers and Electro Optics CLEO 2022 Proceedings, 2022
Simulation of an EOT Based Flexible Plasmonic Metagrating Embedded with Au-MNSAs for Temperature Sensing in NIR Communication Band Optics Infobase Conference Papers, 2022
Advancements in EOT Driven Artificially Engineered Flat Optical Surfaces for Next-Generation Nanophotonic Applications SK Verma OPTCT+SenCity 2026 , 2026 2026
Simulation of an Extra-Ordinary IR Transmission Based Plasmonic Metasurface Filter Resonating at 2.1 𝜇𝑚 B Jatav, SK Verma OPTCT+SenCity 2026 , 2026 2026
Laser sintering development of printed electronics for in-space applications E Schlake, SK Verma, N Kandadai Laser Applications in Microelectronic and Optoelectronic Manufacturing … , 2026 2026
Data-driven modeling and experimental validation of the laser sintering process for the printed silver nanoparticles ink for in-space manufacturing of printed electronics SK Verma, E Schlake, N Kandadai International Journal of Heat and Mass Transfer 256, 127889 , 2026 2026 Citations: 1
Laser sintering of electrohydrodynamic inkjet-printed silver in microgravity for in-space manufacturing of electronic devices E Schlake, SK Verma, L Jiang, P Zhang, H Qin, N Kandadai npj Advanced Manufacturing 2 (1), 42 , 2025 2025 Citations: 7
Highly Sensitive Graphene-Assisted Large-Area Kapton-Based Flexible Surface Plasmon Resonance Biosensor for Enzymatic Glucose Detection Y Singh, SK Verma, N Kandadai, H Subbaraman ACS Applied Materials & Interfaces 17 (32), 45527-45537 , 2025 2025 Citations: 3
Laser sintering of silver-palladium ink for on-demand manufacturing of electronics for space applications E Schlake, SK Verma, N Kandadai Scientific Reports 15 (1), 27412 , 2025 2025 Citations: 5
A graphene integrated Kapton based flexible and highly sensitive plasmonic sensor for uric acid sensing SK Verma, Y Singh, H Subbaraman, N Kandadai Sensors and Actuators Reports 9, 100337 , 2025 2025 Citations: 9
The Effect of Mie-Scattering on Propagating Surface Plasmons SK Verma, Y Singh, D Duryea, H Subbharamn, N Kandadai CLEO: Science and Innovations, JPS100_98 , 2025 2025
Modeling the selective laser sintering of printed silver nanoparticle ink on a flexible substrate SK Verma, E Schlake, N Kandadai Laser-based Micro-and Nanoprocessing XIX 13351, 194-199 , 2025 2025 Citations: 2
Plasmonic Metribuzin Sensor by using synthesized CuO NPs decorated graphene oxide nanocomposite P Maurya, SK Verma, SK Srivastava, A Mishra, R Verma Microchemical Journal 207, 112008 , 2024 2024 Citations: 7
Thermal Conductivity Measurement of a Thin Layer of The Single Crystals of SnO Using Time Domain Thermoreflectance SK Verma, S Chae, N Kandadai Frontiers in Optics, JTu5A. 10 , 2024 2024
Selective Tuning in LASiS Synthesized TiO2 Nanoparticles Ink Based Surface Plasmons SK Verma, DZ Duryea, Y Singh, H Subbaraman, N Kandadai 2024 IEEE International Flexible Electronics Technology Conference (IFETC), 1-3 , 2024 2024
Experimental demonstration of Ge2Sb2Te5 loaded 1-D plasmonic metasurface perfect absorber for near-IR wavelength regime SK Verma, M Jangra, D Arnab, SK Srivastava Optics Letters 49 (16), 4638-4641 , 2024 2024 Citations: 6
Experimental demonstration of a Fano resonant hybrid plasmonic metasurface absorber for the O and E bands of the optical communication window SK Verma, SK Srivastava JOSA B 41 (2), 356-363 , 2024 2024 Citations: 18
Experimental Demonstration of Fano Resonance Based One Dimensional Plasmonic Metasurface Absorber for Refractive Index Sensing in NIR Regime SK Verma, SK Srivastava Laser Science, JW4A. 45 , 2023 2023
Simulation of a Large Dynamic Range Self-Referenced Plasmonic Metasurface Sensor based on Extra-Ordinary Transmission SK Verma, SK Srivastava Optica Sensing Congress 1 (1), SM2D. 4 , 2023 2023
All metal 1D plasmonic metasurface broadband absorber for refractive index sensing in Mid-IR regime SK Verma, SK Srivastava META-2023 1 (1), pp-1635 , 2023 2023
Simulation Study of A One Dimensional All Metal Narrow Band Plasmonic Metasurface Absorber in Visible Wavelength Range SK Verma, SK Srivastava PHOTONICS-2023 1 (1) , 2023 2023
GST Loaded SiO 2 Box Resonator Fabricated on Si for Amplitude Tunable Near-IR Absorber M Jangra, SK Verma, SK Srivastava, A Datta IEEE Photonics Technology Letters 35 (18), 978-981 , 2023 2023 Citations: 3
MOST CITED SCHOLAR PUBLICATIONS
Giant Extra-Ordinary Near Infrared Transmission from Seemingly Opaque Plasmonic Metasurface: Sensing Applications SK Verma, SK Srivastava Plasmonics 17, 653–663 , 2022 2022 Citations: 23
Experimental demonstration of a Fano resonant hybrid plasmonic metasurface absorber for the O and E bands of the optical communication window SK Verma, SK Srivastava JOSA B 41 (2), 356-363 , 2024 2024 Citations: 18
Single step fabricated low cost and flexible Fano resonant all-metal plasmonic metasurface absorber SK Verma, SK Srivastava IEEE Photonics Technology Letters 35 (17), 923-926 , 2023 2023 Citations: 17
Plasmon mediated extra-ordinary optical transmission through an apertureless plasmonic metagrating SK Verma, SK Srivastava Applied Physics Letters 122 (17), 171705-1-6 , 2023 2023 Citations: 11
A graphene integrated Kapton based flexible and highly sensitive plasmonic sensor for uric acid sensing SK Verma, Y Singh, H Subbaraman, N Kandadai Sensors and Actuators Reports 9, 100337 , 2025 2025 Citations: 9
Laser sintering of electrohydrodynamic inkjet-printed silver in microgravity for in-space manufacturing of electronic devices E Schlake, SK Verma, L Jiang, P Zhang, H Qin, N Kandadai npj Advanced Manufacturing 2 (1), 42 , 2025 2025 Citations: 7
Plasmonic Metribuzin Sensor by using synthesized CuO NPs decorated graphene oxide nanocomposite P Maurya, SK Verma, SK Srivastava, A Mishra, R Verma Microchemical Journal 207, 112008 , 2024 2024 Citations: 7
High performance extra-ordinary optical transmission based self-referenced plasmonic metagrating sensor in the NIR communication band SK Verma, SK Srivastava Physica Scripta 98 (5), 055515 , 2023 2023 Citations: 7
Experimental demonstration of Ge2Sb2Te5 loaded 1-D plasmonic metasurface perfect absorber for near-IR wavelength regime SK Verma, M Jangra, D Arnab, SK Srivastava Optics Letters 49 (16), 4638-4641 , 2024 2024 Citations: 6
Laser sintering of silver-palladium ink for on-demand manufacturing of electronics for space applications E Schlake, SK Verma, N Kandadai Scientific Reports 15 (1), 27412 , 2025 2025 Citations: 5
Highly Sensitive Graphene-Assisted Large-Area Kapton-Based Flexible Surface Plasmon Resonance Biosensor for Enzymatic Glucose Detection Y Singh, SK Verma, N Kandadai, H Subbaraman ACS Applied Materials & Interfaces 17 (32), 45527-45537 , 2025 2025 Citations: 3
GST Loaded SiO 2 Box Resonator Fabricated on Si for Amplitude Tunable Near-IR Absorber M Jangra, SK Verma, SK Srivastava, A Datta IEEE Photonics Technology Letters 35 (18), 978-981 , 2023 2023 Citations: 3
Modeling the selective laser sintering of printed silver nanoparticle ink on a flexible substrate SK Verma, E Schlake, N Kandadai Laser-based Micro-and Nanoprocessing XIX 13351, 194-199 , 2025 2025 Citations: 2
Data-driven modeling and experimental validation of the laser sintering process for the printed silver nanoparticles ink for in-space manufacturing of printed electronics SK Verma, E Schlake, N Kandadai International Journal of Heat and Mass Transfer 256, 127889 , 2026 2026 Citations: 1
Simulation of an EOT Based 1D-Plasmonic Metasurface Sensor for Absorptive Analytes SK Verma, SK Srivastava CLEO-2022, JTu3B.26 , 2022 2022 Citations: 1
Advancements in EOT Driven Artificially Engineered Flat Optical Surfaces for Next-Generation Nanophotonic Applications SK Verma OPTCT+SenCity 2026 , 2026 2026
Simulation of an Extra-Ordinary IR Transmission Based Plasmonic Metasurface Filter Resonating at 2.1 𝜇𝑚 B Jatav, SK Verma OPTCT+SenCity 2026 , 2026 2026
Laser sintering development of printed electronics for in-space applications E Schlake, SK Verma, N Kandadai Laser Applications in Microelectronic and Optoelectronic Manufacturing … , 2026 2026
The Effect of Mie-Scattering on Propagating Surface Plasmons SK Verma, Y Singh, D Duryea, H Subbharamn, N Kandadai CLEO: Science and Innovations, JPS100_98 , 2025 2025
Thermal Conductivity Measurement of a Thin Layer of The Single Crystals of SnO Using Time Domain Thermoreflectance SK Verma, S Chae, N Kandadai Frontiers in Optics, JTu5A. 10 , 2024 2024
