Rajan Jha

• PhD
• Faculty Member at Indian Institute of Technology Bhubaneswar

Efficient road traffic monitoring has a significant impact on the social and economic welfare of modern cities. Hence, developing a sensitive detection system that identifies various features of moving vehicles in real-time could suffice the demand for an integrable and competent traffic surveillance network. In this work, we propose and demonstrat...

A system is proposed for the efficient coupling of plasmon‐enhanced polarized single photons into a 1D apodized hybrid photonic‐plasmonic (HPP) cavity structure, to realize cavity quantum electrodynamics (QED). The HPP cavity is formed by placing a gold nanorod (GNR) on an apodized 1D photonic crystal (PhC) cavity designed on a diamond waveguide. I...

We investigate the strain and temperature dependence coefficients of the Brillouin frequency shift in a ZBLAN (ZrF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> -BaF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -LaF <sub xmlns:mml="htt...

A one-sided slotted photonic crystal cavity structure on an optical nanofiber is proposed to realize cavity quantum electrodynamics. The device can unidirectionally couple single photons with an efficiency of ~90% into the nanofiber fundamental mode.

Improving the functionality of an optical sensor on a prefabricated platform relies heavily on an optical signal conditioning method that actively modulates optical signals. In this work, we present a method for active modulation of an optical sensor response that uses fiber modal interferometers integrated in parallel. Over a broad frequency range...

Improving the functionality of an optical sensor on a prefabricated platform relies heavily on an optical signal conditioning method that actively modulates optical signals. In this work, we present a method for active modulation of an optical sensor response that uses fiber modal interferometers integrated in parallel. Over a broad frequency range...

Brillouin optical correlation-domain reflectometry (BOCDR) allows for relatively high spatial resolution and random accessibility with single-end light injection into the sensing fiber. Typically, BOCDR relies on directly modulating the laser diode’s driving current, which facilitates sinusoidal frequency modulation for distributed sensing but also...

Surface characterization is essential for a technical evaluation of device performance and to assess surface dynamics in fabrication units. In this regard, a number of surface profiling techniques have been developed that accurately map sample topography but have significantly limited detection range. Here, we demonstrate a cascaded non-contact fib...

Recirculating aquaculture systems (RAS) have been rising quickly in the last decade, representing a new way to farm fish with sustainable aquaculture practices. This system is an environmentally and economically sustainable technology for farming aquatic organisms by reusing the water in production. RAS present some benefits compared with other aqu...

Fiber optic interferometry combined with recognizing elements has attracted intensive attention for the development of different biosensors due to its superior characteristic features. However, the immobilization of sensing elements alone is not capable of low-concentration detection due to weak interaction with the evanescent field of the sensing...

We report a slot waveguide-enhanced asymmetric photonic crystal optical nanofiber (ONF) cavity to realize cavity quantum electrodynamics. We show that the device can strongly enhance the spontaneous emission of a single quantum emitter leading to a Purcell factor as high as 106 and enables single-photon coupling efficiency as high as 86% into fiber...

We report a slot waveguide-enhanced asymmetric photonic crystal optical nanofiber (ONF) cavity to realize cavity quantum electrodynamics. We show that the device can strongly enhance the spontaneous emission of a single quantum emitter leading to a Purcell factor as high as 106 and enables single-photon coupling efficiency as high as 86% into fiber...

Over the last 20 years, optical fiber-based devices have been exploited extensively in the field of biochemical sensing, with applications in many specific areas such as the food processing industry, environmental monitoring, health diagnosis, bioengineering, disease diagnosis, and the drug industry due to their compact, label-free, and highly sens...

We report a slot waveguide-enhanced asymmetric photonic crystal optical nanofiber (ONF) cavity to realize cavity quantum electrodynamics. We show that the device can strongly enhance the spontaneous emission of a single quantum emitter leading to a Purcell factor as high as 106 and enables single-photon coupling efficiency as high as 86% into fiber...

Tightly focused beam scattering through a nanoparticle (NP) influences their plasmonic properties and shows significant intensity enhancement in the near-field of the NP. Such beams with high numerical aperture (NA) and high convergence angle can produce a tight focal spot. Deviation of the incident beam wave-front from its actual reference sphere...

Dynamic magnetic field detection is essential in various fields spanning over industrial monitoring to scientific explorations. Development of a high resolution magnetometer that is operable over broad frequency range has remained elusive. In this work, we report an optical magnetometer that consists of a SMF-PCF fiber configuration and a flexible...

A single-sided photonic crystal cavity structure on an optical nanowire is proposed to realize cavity quantum electrodynamics. Unidirectional coupling of single photons can be achieved into the guided mode of nanowire from a quantum emitter.

We present a topographical characterization system for surfaces analysis utilizing fiber-based cavity interferometers’ system. It provides a broad range of displacement sensing by achieving high-resolution and precise measurements, essential for material analysis and nanotechnology applications.

An enhancement in near-field intensity is observed when a tightly focused beam having high convergence angle is scattered through a nanoparticle (NP). The average intensity enhancement is explained using Richard and Wolf’s formalism followed by Mie theory and multipole expansion approach. Variation in convergence angle affects the enhancement in ne...

The photonic spin Hall effect (PSHE) has been intensively studied and widely applied, especially in spin photonics. In this paper, we present the analysis of PSHE in the Plexcitonic system. The signature of the Plexciton is studied by implanting an organic semiconductor layer over the plasmon active metal. We report a high spin-dependent transverse...

Interactions of gold and silver spherical nanoparticles (NPs) of a wide range of radius size with tightly focused beams are investigated for a wide range of wavelengths. The scattering of tightly focused beams with a single NP of varying size is examined using a generalized Mie theory and average intensity enhancement in the near-field due to local...

Pollution monitoring in waterways and oceans is often performed in a laboratory on samples previously taken from the environment. The integration of molecular imprinting polymer nanoparticles (MIP-NPs) with a novel, to the best of our knowledge, fiber optic interferometer allowed a fast and selective detection of water pollutant 2,4-Dichlorophenol...

Nanoparticles (NPs) show intensity enhancement in the near-field due to their plasmonic response when illuminated by a tightly focused beam having a high numerical aperture. The effect in intensity enhancement is influenced by the number of modes. Some specific properties such as directivity, confinement, etc. are possessed by each of these modes....

In this work, a wavefront division interferometry method for determining the topological charge (l) of vortex beams (VB) is proposed and utilized for the detection of beam displacement. The method uses Fresnel biprism as a single element to determine vortex charge for up to l = ±10. Additionally, the interference pattern configuration is utilized t...

Near-field intensity enhancement due to the plasmonic response of nanoparticles is investigated with the Mie theory and multipole expansion for an aberrated focusing system. Spherical aberration and defocusing are considered as an aberration in the focusing system.

This numerical research presents a simple hybrid structure comprised of TiO2-Cu-BaTiO3 for a modified Kretschmann configuration that exhibits high sensitivity and high resolution for biosensing applications through an angular interrogation method. Recently, copper (Cu) emerged as an exceptional choice as a plasmonic metal for developing surface pla...

We report a new gateway towards the light-matter interaction of spontaneous emission from a quantum emitter (QE) in optical nanofiber (ONF) based on nanocavities tilted by some angle with respect to the plane of the fiber cross-section. This structure is designed by three-dimensional finite-difference time-domain simulations to enhance the spontane...

Wearable technologies have achieved tremendous success in medical‐grade human vital signal monitoring. Herein, a unique geometry (balloon shaped) and usage of very economical polymer embedded single mode fiber based modal interferometry that not only overcome the mechanical strength restrictions of most of the fiber wearables but also fulfil the tw...

Histamine is a biologically active molecule that serves as a reliable predictor of the quality of fish. In this work, authors have developed a novel humanoid-shaped tapered optical fiber (HTOF) biosensor based on the localized surface plasmon resonance (LSPR) phenomenon to detect varying histamine concentrations. In this experiment, a novel and dis...

This theoretical work proposed an ultra-high sensitive hybrid structure for modified Kretschmann configuration comprised of copper-2D material layer on CaF2 prism for biosensing applications through angular interrogation method. Here, it is reported that such a configuration in association with the low refractive index CaF2 prism provides major con...

In this present paper, we propose a surface plasmon resonance(SPR)sensor having better performance parameters based on Kretschmann configuration. The proposed SPR sensor is a modified Kretschmann configuration comprised of BK7 prism-Cu-Pt-Graphene/BP/WS2. The bimetallic layer provides consistent enhancement of sensitivity over other SPR structures....

Considering the promising utility of devices operating for high magnetic fields in noninvasive medical diagnostic applications such as magnetic resonance imaging, a microfiber-based magnetometer operating for an extensive dynamic range actuated via NiFe 2 O 4 ferrite fluid is presented and proposed for the first time in this paper. NiFe 2 O 4 nanop...

Aiming at the requirement of high precision and long life in tasks of mechanical and navigation industries, a highly sensitive and compact, magnetorheological fluid film-suspended nonadiabatic biconical tapered optical fiber interferometer-based vector magnetometer has been proposed and demonstrated in the manuscript. The reported magnetometer keep...

The estimation of vortex convection velocity and frequency of vortices is a challenging task that requires sophisticated experimental and computational techniques. Several methods have been developed to measure the velocity of vortices, including vortex flowmeters (vortex shedding flow meter, Karman vortex flow meter), pressure sensitive paints (PS...

A slotted photonic crystal cavity structure on an optical nanofiber is proposed to realize cavity quantum electrodynamics. The device has a Q -factor of ∼ 1100 and excellent single photon coupling to the nanofiber fundamental mode.

Flexible arch type polydimethylsiloxane (PDMS) embedded single mode fiber (SMF) based optical wearable interferometric system is presented for pulse wave detection that overcomes the mechanical constraints associated with other fiber-based wearables.

An attempt has been made to enhance the sensitivity of a high-sensitive surface plasmon resonance (SPR) biosensor with an aluminium-cobalt bimetallic layer covered by a tungsten disulfide-graphene heterostructure. A thin layer of cobalt coated on an aluminium layer contributed substantially to increase the sensor performance. The use of Al and Co m...

A hybrid structure comprised of Cu-BaTiO3-BP-graphene on a BK7 prism as a modified Kretschmann configuration for biosensing application is proposed and numerically analyzed using the transfer matrix method (TMM). Numerical results show that with appropriate optimization of the thickness of copper (Cu), barium titanate (BaTiO3), and the number of la...

We propose a system for guiding plasmon-enhanced polarized single photons into optical nanowire (ONW) guided modes. It is shown that spontaneous emission properties of quantum emitters (QEs) can be strongly enhanced in the presence of gold nanorod dimer (GNRD) leading to the emission of highly polarized and bright single photons. We have calculated...

Here, we report a photonic spin Hall effect (PSHE), i.e., splitting of opposite spin in a transverse direction using a multi-layered metallo-dielectric heterostructure by hybridization of a Tamm plasmon polariton and a surface plasmon polariton. The underlying mechanism of PSHE is also explained using the concept of superposition of normal and abno...

In this paper, we propose the implementation of few layers of 2D materials in plexcitonic sensor for sensitivity enhancement. The positioning of the graphene layer implantation in such structure affects the sensitivity. The presence of graphene in contact with analyte offers ~ 14% increase in the sensitivity of a bare plexcitonic sensor. Also, the...

A Surface Plasmon Resonance (SPR) based biosensor utilizing copper and BaTiO 3 with addition layer coating of graphene and Black Phosphorous(BP) structures in kretschmann configuration for the detection of biomolecules event is analysed and optimized numerically using transfer matrix method. The strategy consist of placing the sensing medium on the...

We report on a simulation of a nanophotonic cavity constructed by designing periodic holes on an optical nanofiber to realize light–matter interaction. The cavity is designed using finite-difference time-domain simulations to maximize the coupling of spontaneous emission from a quantum emitter into fiber-guided modes. We systematically analyze the...

Future wearable devices for health monitoring, robotics, and ultraprecise industrial positioning necessitate flexible optical systems. Here, an optical microfiber interferometer‐based wearable system is demonstrated with wavelength interrogation that overcomes the limits of commonly reported electrical, optical, and material‐based flexible devices....

The performance of prism-based surface plasmon resonance sensor utilizing kretschmann configuration composed of thin metallic (Cu–Co) film coated with 2D material such as BP/Graphene layer is investigated theoretically based on angular interrogation method. It is observed that optimizing the thickness of bimetallic (Cu–Co) and BP/Graphene layers, t...

Cu2ZnSnS4 (CZTS) has been widely used as absorber layer for an alternative cadmium free thin film solar cell material. However, in some of the CZTS based solar cell still use cadmium sulphide or cadmium selenide as buffer layer. Because of its toxic nature, it can have very harmful effect on environment. In this work, we have simulated a CZTS-Metal...

As factories and vehicles become more automated, accurate and low-latency sensing of motor shaft speed and position is critical for process control, system reliability, and safety. To address these needs, a highly precise and fast vector magnetometer is required that has the capability to detect magnetic field variations also at tiny angles. We pre...

The article describes the development of a hetro-core optical fiber sensor structure based on localized surface plasmon resonance (LSPR) for the detection of cardiac troponin I (cTnI) solution. This was accomplished by fabricating a single-mode fiber - multimode fiber - single-mode fiber (SMS) structure. Then, fiber structure is immobilized with go...

The directional coupling of single photon emission from nitrogen vacancy (NV–) emitters to optical systems for various applications requires a suitable interface between NV– emitters and optical waveguides. Unidirectional coupling of photons may have significant importance in next generation quantum technology such as quantum and complex optical ne...

This paper describes a compact refractometer in visible with optical bounds states in the continuum (BICs) using silicon nitride (Si3N4) based sub-wavelength medium contrast gratings (MCGs). The proposed device is highly sensitive to different polarization states of light and allows a wide dynamic range from 1.330 (aqueous environment) to 1.420 (bi...

Concatenated modal interferometers-based multipoint monitoring system for detection of amplitude, frequency, and phase of mechanical vibrations is proposed and demonstrated. The sensor probes are fabricated using identical photonic crystal fiber (PCF) sections and integrated along a single fiber channel to act as a compact and efficient sensing sys...

We experimentally demonstrated a periodically collapsed solid-core photonic crystal fiber (SCPCF) based modal interferometer for sensing refractive index (RI) of chemicals. A given piece of SCPCF is periodically collapsed using an easily and widely available commercial splicer machine and a micropositioner. The distance between the collapsed and nu...

Magnetic field sensor operating for high magnetic fields plays a critical role in non-invasive medical diagnostic applications such as magnetic resonance imaging. Considering this fact, a microfiber-based magnetometer functioning for a large dynamic range of magnetic field actuated via NiFe2O4 ferrite fluid is presented and proposed. The relevant t...

Optical interferometry integrated with molecularly imprinting polymer (MIP) can be an advanced futuristic approach for developing ultrasensitive and selective remote detection technology. This cohesive strategy has enormous potential for developing next-generation online bio-molecule detection systems riding on the benefits of artificial complement...

In this work, beam tilt is detected by wavefront division interference of vortex beam using Fresnel biprism. The sensitivity is found to vary with vortex order, enabling detection of minute tilt angles (~ 10 ⁻⁴ rad).

“Invited” labels were added to the titles of two articles appearing in this feature issue [J. Opt. Soc. Am. B 38, F38 (2021)JOBPDE0740-322410.1364/JOSAB.434413; J. Opt. Soc. Am. B 38, F115 (2021)JOBPDE0740-322410.1364/JOSAB.437891].

In this introduction, we provide an overview of the papers that were accepted for publication in the feature issue on specialty optical fiber modeling, fabrication, and characterization. A total of 22 papers were published in JOSA B. This feature issue presents cutting-edge research on specialty optical fibers and highlights recent developments in...

Alanine aminotransferase (ALT), a critical component of human blood, is inextricably associated with liver injury. The current study develops a novel biosensor based on the localized surface plasmon resonance (LSPR) principle for the detection of ALT analytes at concentrations ranging from 0 to 1000 Units per liter (U/L). According to the authors'...

Optical segments based flexible systems are the key for the development of futuristic advanced wearable devices for health monitoring, robotics, and ultraprecision positioning in industrial applications. Here, we have demonstrated an processed optical microfiber based multifunctional sensing system, which overcomes the various limitations of most w...

In this work, tapered/etched multicore fiber (MCF) probes are spliced with multimode fiber (MMF) to fabricate the sensor structure. To improve sensitivity, gold nanoparticles (AuNPs) and molybdenum disulfide nanoparticles (MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -NPs) are used to im...

An optical signal conditioning technique for dynamic modulation of signals and real-time monitoring of events is pivotal for developing various optical systems at micro/nano dimensions. The utilities of such technique include controllable signal enhancement and distinctive response towards external stimuli, with reconfigurable operational range. He...

An optical signal conditioning technique for dynamic modulation of signals and real-time monitoring of events is pivotal for developing various optical systems at micro/nano dimensions. The utilities of such technique include controllable signal enhancement and distinctive response towards external stimuli, with reconfigurable operational range. He...

In this paper the performance of surface plasmon resonance (SPR) biosensor in modified kretchmann configuration utilizing nanocomposite layer consisting of nickel and ZnO as plasmonic material is analyzed numerically using N-layered transfer matrix method. The performance parameters of proposed sensor are investigated in terms of sensitivity (S), d...

Negatively charged nitrogen vacancy ( ${{\rm{NV}}^ -}$ ) centers in diamond are required to be coupled to optical systems for various applications. A slowly varied tapered waveguide displays a near-unity power transfer from an optical fiber to on-chip photonic devices. This physical situation refers to an adiabatic transition of photons from a high...

The demand of single photon coupling to optical systems requires a suitable interface between negatively charged Nitrogen Vacancy (NV-) emitters in diamond to waveguides or optical circuits for applications in quantum network systems and in unidirectional emission with controlled photon states. Here, we propose a hybrid asymmetric structure of elli...

The sample geometry by way of its influence on stress distribution is expected to control the superelastic and fatigue behavior of Nitinol. A variety of sample geometries are reported in literature for studying the fatigue behavior of Nitinol and it is unclear which geometry is the most suitable. To establish this, we conducted finite element simul...

Highly sensitive surface plasmon resonance (SPR) sensor consisting of Ag-Pt bimetallic films sandwiched with 2D materials black phosphorus (BP) and graphene over Pt layer in Kretschmann configuration is analyzed theoretically using the transfer matrix method. Numerical results show that upon suitable optimization of thickness of Ag-Pt layers and th...

The combined approach of optical fiber interferometry with molecular imprinting technology has shown a tremendous potential for developing a specific and sophisticated bio‐detection system with high degree of resolution and sensitivity. However, the specificity limitation of the fiber optic sensors renders them unsuitable for several key applicatio...

In this work, a localized plasmon-based sensor is developed for para-cresol (p-cresol) - a water pollutants detection. A nonadiabatic 40 μm of tapered optical fiber (TOF) has been experimentally fabricated and computationally analyzed using beam propagation method. For optimization of sensor’s performance, two probes are proposed, where probe 1 is...

Highly sensitivity Surface Plasmon resonance (SPR) sensor consisting of Ag-Pt bimetallic films sandwiched with 2D materials Black Phosphorus (BP) and Graphene over Pt layer in Kretschmann configuration is analyzed theoretically using the Transfer Matrix Method. Numerical results shows that upon suitable optimization of thickness of Ag-Pt and number...

Concatenated modal interferometers based multipoint sensing system for detection of instantaneous amplitude, frequency, and phase of mechanical vibrations is proposed and demonstrated. The sensor probes are fabricated using identical photonic crystal fiber (PCF) sections and integrated along a single fiber channel to act as a compact and efficient...

This article reported about the ultraviolet (UV) radiation effect on the resonance frequency response of a AT-cut piezoelectric quartz crystal. A large resonance frequency upshift was observed when the quartz crystal was irradiated by UV light of 355-nm wavelength using a Q-switched pulsed Nd:YVO4 UV laser. The dynamic frequency response behavior w...

We report coupling between surface plasmon polariton (SPP) and surface exciton polariton (SEP) as hybrid mode; surface plasmon exciton polariton (SPEP) that can be utilized for highly sensitive and accurate refractive index monitoring. The proposed structure comprises of a thin layer of organic semiconductor; J-aggregate cyanine dye (5,5′,6,6′-tetr...

We propose and demonstrate an in-line Mach–Zehnder interferometer (IMZI) as an optical hydrophone. The IMZI is fabricated by creating two tapers in the single-mode fiber (SMF), and the two tapered sections are separated by a small section of untapered SMF. To achieve higher sensitivity, this IMZI is attached to a circular natural rubber (NR) diaphr...