High-throughput imaging surface plasmon resonance biosensing based on ultrafast two-point spectral-dip tracking scheme

Wavelength interrogation surface plasmon resonance imaging (λSPRi) has potential in detecting 2-dimensional (2D) sensor array sites, but the resonance wavelength imaging rate limits the application of detecting biomolecular binding process in real time. In this paper, we have successfully demonstrated an ultrafast λSPRi biosensor system. The key feature is a two-point tracking algorithm that drives the liquid crystal tunable filter (LCTF) to achieve fast-tracking of the resonance wavelength movement caused by the binding of target molecules with the probe molecules on the sensing surface. The resonance wavelength measurement time is within 0.25s. To date, this is the fastest speed ever reported in λSPRi. Experiment results show that the sensitivity and dynamic are 2.4 × 10−6 RIU and 4.6 × 10−2 RIU, respectively. In addition, we have also demonstrated that the system has the capability of performing fast high-throughput detection of biomolecular interactions, which confirms that this fast real-time detecting approach is most suitable for high-throughput and label-free biosensing applications

A Broadly Tunable Surface Plasmon-Coupled Wavelength Filter for Visible and Near Infrared Hyperspectral Imaging

Hyperspectral imaging is a set of techniques that has contributed to the study of advanced materials, pharmaceuticals, semiconductors, ceramics, polymers, biological specimens, and geological samples. Its use for remote sensing has advanced our understanding of agriculture, forestry, the Earth, environmental science, and the universe. The development of ultra-compact handheld hyperspectral imagers has been impeded by the scarcity of small widefield tunable wavelength filters. The widefield modality is preferred for handheld imaging applications in which image registration can be performed to counter scene shift caused by irregular user motions that would thwart scanning approaches. In the work presented here an electronically tunable widefield wavelength filter has been developed for hyperspectral imaging applications in the visible and near-infrared region. Conventional electronically tunable widefield imaging filter technologies include liquid crystal-based filters, acousto-optic tunable filters, and electronically tuned etalons; each having its own set of advantages and disadvantages. The construction of tunable filters is often complex and requires elaborate optical assemblies and electronic control circuits. I introduce in the work presented here is a novel widefield tunable filter, the surface plasmon coupled tunable filter (SPCTF), for visible and near infrared imaging. The SPCTF is based on surface plasmon coupling and has simple optical design that can be miniaturized without sacrificing performance. The SPCTF provides diffraction limited spatial resolution with a moderately narrow nominal passband (\u3c10 \u3enm) and a large spurious free spectral range (450 nm-1000 nm). The SPCTF employs surface plasmon coupling of the π-polarized component of incident light in metal films separated by a tunable dielectric layer. Acting on the π-polarized component, the device is limited to transmitting 50 percent of unpolarized incident light. This is higher than the throughput of comparable Lyot-based liquid crystal tunable filters that employ a series of linear polarizers. In addition, the SPCTF is not susceptible to the unwanted harmonic bands that lead to spurious diffraction in Bragg-based devices. Hence its spurious free spectral range covers a broad region from the blue through near infrared wavelengths. The compact design and rugged optical assembly make it suitable for hand-held hyperspectral imagers. The underlying theory and SPCTF design are presented along with a comparison of its performance to calculated estimates of transmittance, spectral resolution, and spectral range. In addition, widefield hyperspectral imaging using the SPCTF is demonstrated on model sample

High-speed surface profilometry based on an adaptive microscope with axial chromatic encoding

An adaptive microscope with axial chromatic encoding is designed and developed, namely the AdaScope. With the ability to confocally address any locations within the measurement volume, the AdaScope provides the hardware foundation for a cascade measurement strategy to be developed, dramatically accelerating the speed of 3D confocal microscopy

Dispersion tailoring in both integrated photonics and fiber-optic based devices

Tesis por compendio[EN] This Thesis focuses on the study, implementation and characterization of chromatic dispersion tailoring employing both optical fiber and photonic integrated waveguides. Chromatic dispersion causes that the different spectral components of an optical pulse travel at different velocities. This effect can be separated into two different fundamental contributions, material dispersion and waveguide dispersion. Chromatic dispersion can be tailored through the design of the structural parameters of the device in order to obtain specific characteristics in the resulting dispersion profile such as low values of dispersion and/or zero dispersion at a desired wavelength, for example. This approach is very useful in dispersion-dependent applications. In this PhD, we investigate chromatic dispersion tailoring in two different transmission mediums, photonic integrated waveguides and optical fiber. In the first case, two different geometries of Silicon-on-Insulator (SOI) integrated waveguides, strip and slot, are considered. By varying structural parameters such as the cross-section, aspect ratio or fill factor, different chromatic dispersion profiles are obtained. In addition, the influence of the slot location is evaluated. This study is carried out using simulation software in order to obtain the effective refractive index profile as a function of wavelength, which is later differentiated to obtain the final dispersion values. Besides, chromatic dispersion in both waveguide geometries is experimentally measured using an interferometer technique. In the second case, the chromatic dispersion present in a tapered fiber is studied. A tapered fiber consists of a narrow waist located between two transition regions and it allows the modification of the conventional propagation conditions due to the interference between the modes propagating through the waist. This interference between modes creates a transmission pattern which depends on the waist length and the effective refractive indexes of the modes travelling through the waist. By applying stress to the tapered fiber its interference pattern can be modified. Chromatic dispersion profile of tapered fibers is obtained, tailored and compared with the dispersion profile of conventional single-mode fibers.[ES] Esta Tesis se centra en el estudio, implementación y caracterización del control de la dispersión cromática empleando tanto fibra óptica como guías integradas fotónicas. La dispersión cromática provoca que las distintas componentes espectrales asociadas con el pulso óptico viajen a diferentes velocidades. Este efecto puede ser dividido en sus dos contribuciones fundamentales, la dispersión del material y la dispersión de la guía. La dispersión cromática puede ser controlada a través del diseño de los parámetros estructurales del dispositivo para poder obtener así determinadas características en el perfil de dispersión resultante como por ejemplo bajos valores o localización de la longitud de onda de dispersión cero en una longitud de onda deseada. Este método es muy útil en aplicaciones dependientes de la dispersión. En esta Tesis, investigamos el control de la dispersión cromática en dos medios de transmisión diferentes, las guías fotónicas integradas y la fibra óptica. En el primer caso, se consideran dos geometrías diferentes de guías integradas en silicio, las guías convencionales y las guías ranuradas. Mediante la modificación de los parámetros estructurales como la sección transversal de la guía, su relación de aspecto o el factor de llenado, se obtienen diferentes perfiles de dispersión cromática. Además, se evalúa la influencia de la situación de la ranura. Mediante software de simulación, se obtiene el perfil de índice de refracción efectivo en función de la longitud de onda, que posteriormente se deriva y se obtiene el valor de la dispersión. Asimismo, se mide experimentalmente la dispersión en ambas geometrías utilizando una técnica interferométrica. En el segundo caso, se analiza la dispersión cromática que presenta una fibra de tipo taper. Esta geometría consiste en una cintura estrecha situada entre dos regiones de transición y permite la modificación de las condiciones de propagación convencionales debido a la interferencia entre los modos que se propagan por la cintura, que crea un patrón de transmisión dependiente de la longitud de la cintura y de los índices efectivos de los modos. Aplicando tensión sobre la fibra, su patrón de interferencia puede ser modificado. La dispersión cromática de las fibras taper se obtiene, se modifica y se compara con el perfil de dispersión de una fibra convencional.[CA] La tesi a exposar se centra en l'estudi, implementació i caracterització del control de la dispersió cromàtica empleant la fibra òptica i les guies integrades fotòniques. La dispersió cromàtica provoca que els distints components espectrals associats amb la pols òptica viatgen a diferents velocitats. Aquest pot dividir-se en les dos contribucions fonamentals corresponents: la dispersió del material i la dispersió de la guia. La dispersió cromàtica pot controlar-se a través del disseny dels paràmetres estructurals del dispositiu per poder obtindre aixi determinades característiques en el perfil de dispersió resultant, com per exemple, baixos valors o localizació de la longitud d'ona de dispersió zero a una longitud d'ona desitjada. No obstant això, aquest mètode és molt útil en aplicacions depenents de la dispersió. A més a més, investiguem el control de dispersió cromàtica en dos mitjans de transmissió diferents, les guies fotòniques integrades i la fibra òptica. D'una banda, es consideren dos geometries diferents de guies integrades en silici, les guies convencionals i les ranurades. Mitjançant la modificació dels paràmetres estructurals com la secció transversal de la guia, la relació d'apecte o el factor d'ompliment, obtenim diferents perfils de dispersió cromàtica. Fins i tot, s'avalua la influència de la situació de la ranura. Mitjançant el programari de simulació, obtenim el perfil d'índex de refracció efectiu en funció de la longitud d'ona, que posteriorment es derivarà i s'obrindrà el valor de la dispersió. Tanmateix, es mesura experimentalment la dispersió en les dos geometries utilitzant una tècnica interferomètrica. D'altra banda, analitzam la dispersió cromàtica que presenta una fibra de tipus taper. Aquesta consisteix en una cintura estreta situada entre dos regions de transició que, ens permet la modificació de les condicions de propagació convencional com a causa d'una interferència entre els modes que es propaguen per la cintura i els índex efectius dels modes. Si apliquem tensió sobre la fibra, el seu patró d'interferència podria ser modificat. La dispersió d'una fibra cromàtica de les fibres taper s'obté, es modific i es compara amb el perfil de dispersió d'una fibra convencional.Mas Gómez, SM. (2015). Dispersion tailoring in both integrated photonics and fiber-optic based devices [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/54113TESISCompendi

Fiber Optic Sensors and Fiber Lasers

The optical fiber industry is emerging from the market for selling simple accessories using optical fiber to the new optical-IT convergence sensor market combined with high value-added smart industries such as the bio industry. Among them, fiber optic sensors and fiber lasers are growing faster and more accurately by utilizing fiber optics in various fields such as shipbuilding, construction, energy, military, railway, security, and medical.This Special Issue aims to present novel and innovative applications of sensors and devices based on fiber optic sensors and fiber lasers, and covers a wide range of applications of optical sensors. In this Special Issue, original research articles, as well as reviews, have been published

Photoactive Materials: Synthesis, Applications and Technology

This book presents a collection of 13 original research articles that focus on the science of light–matter interaction. This area of science has been led to some the greatest accomplishments of the past 100 years, with the discovery of materials that perform useful operations by collecting light or generating light from an outside stimulus. These materials are at the center of a multitude of technologies that have permeated our daily life; every day we rely on quantum well lasers for telecommunication, organic light emitting diodes for our displays, complementary metal–oxide–semiconductors for our camera detectors, and of course a plethora of new photovoltaic cells that harvest sunlight to satisfy our energy needs. In this book, top-rated researchers present their latest findings in the field of nano-particles, plasmonics, semi-conductors, magneto-optics, and holography

LASER Tech Briefs, Spring 1994

Topics in this Laser Tech Brief include: Electronic Components and Circuits. Electronic Systems, Physical Sciences, Materials, Mechanics, Fabrication Technology, and books and reports

Optical MEMS

Optical microelectromechanical systems (MEMS), microoptoelectromechanical systems (MOEMS), or optical microsystems are devices or systems that interact with light through actuation or sensing at a micro- or millimeter scale. Optical MEMS have had enormous commercial success in projectors, displays, and fiberoptic communications. The best-known example is Texas Instruments’ digital micromirror devices (DMDs). The development of optical MEMS was impeded seriously by the Telecom Bubble in 2000. Fortunately, DMDs grew their market size even in that economy downturn. Meanwhile, in the last one and half decade, the optical MEMS market has been slowly but steadily recovering. During this time, the major technological change was the shift of thin-film polysilicon microstructures to single-crystal–silicon microsructures. Especially in the last few years, cloud data centers are demanding large-port optical cross connects (OXCs) and autonomous driving looks for miniature LiDAR, and virtual reality/augmented reality (VR/AR) demands tiny optical scanners. This is a new wave of opportunities for optical MEMS. Furthermore, several research institutes around the world have been developing MOEMS devices for extreme applications (very fine tailoring of light beam in terms of phase, intensity, or wavelength) and/or extreme environments (vacuum, cryogenic temperatures) for many years. Accordingly, this Special Issue seeks to showcase research papers, short communications, and review articles that focus on (1) novel design, fabrication, control, and modeling of optical MEMS devices based on all kinds of actuation/sensing mechanisms; and (2) new developments of applying optical MEMS devices of any kind in consumer electronics, optical communications, industry, biology, medicine, agriculture, physics, astronomy, space, or defense

Optical microsystems based on integrated optics and micromechanics

Optical microsystems based on silicon technology have been studied in this work. Components applying integrated optical structures and microelectromechanical systems (MEMS) have been developed. New functionality, lower component costs, and improved reliability have been aimed at by the integration and miniaturization of the novel concepts. The four components studied in this work represent new ideas based on well established material technologies and manufacturing schemes. The first three components are based silicon integrated optics and the fourth component is based on silicon micromechanics. A novel architecture for a surface plasmon resonance (SPR) sensor based on a silicon nitride slab waveguide structure was proposed and studied. Industrial aspects and feasibility for the practical sensor design of the introduced concept were considered. As a main result a proof-of-concept was shown by demonstrating the device sensitivity to humidity. A surface plasmon sensor fabricated with a silicon nitride waveguide technology has applications as a chemical and biochemical sensor. A thermally tunable integrated optical ring resonator device was developed to study the optical characteristics of a ring resonator, waveguide quality, and electrical characteristics of thermo-optical control with in situ temperature sensing. The device was based on Si3N4 waveguides. The ring perimeter of the resonator was 6.76 mm and the free spectral range was 26 GHz. The thermal control was implemented by using poly-silicon resistive heaters integrated on top of the waveguide layer. The thermal tuning was demonstrated to be a feasible tool for an accurate optical phase control. The measured temperature coefficient of Si3N4 rib waveguide can be applied in the design of future devices based on similar structures. This type of ring resonator structures are suitable for sensing applications, as high refractive index difference enables flexible designs with small radius waveguide bends. New type of integrated optical beam combiner circuits were proposed, designed and fabricated based on a silicon oxynitride waveguide technology, to provide a replacement for optical fiber coupler components in a phased array antenna demonstrator. The insertion loss of the pigtailed devices turned out to be moderately high but the coupling ratio of the 3 dB couplers were better than 47:53, and polarization extinction ratio was above 10 dB. Based on the results of the fabricated test devices the specified optical requirements for a practical application were considered achievable with the proposed SiON technology by further reducing the propagation loss of the waveguide and the excess loss of the 3 dB couplers. Lastly, microelectromechanical variable optical attenuators (VOA) based on the silicon-on-insulator (SOI) technology were developed for optical fiber networks. Two novel VOA architectures were proposed and developed. As a result both configurations were shown to have optical performance satisfying the general requirements set by modern fiber optical networks for VOAs. The major achievement was a reflective type VOA device with low insertion loss below 0.8 dB, ultra-low polarization sensitivity below 0.1 dB, 30 dB dynamic attenuation range, and with optical repeatability better than 0.03 dB.reviewe

Dual-spectral interferometric sensor for quantitative study of protein-DNA interactions

Thesis (Ph.D.)--Boston UniversityThe maintenance and functions of the genome are facilitated by DNA-binding proteins, whose specific binding mechanisms are not yet fully understood. Recently, it was discovered that the recognition and capture ofDNA conformational flexibility and deformation by DNA-binding proteins serve as an indirect readout mechanism for specific recognition and facilitate important cellular functions. Various biophysical techniques have been employed to elucidate this conformational specificity of protein-DNA interactions. These techniques are not sufficiently high-throughput to perform systematic investigation ofvarious protein-DNA complexes and their functions. Microarray-based high-throughput methods enable large-scale and comprehensive evaluation of the binding affmities of protein-DNA interactions, but do not provide conformational information. In this dissertation, we developed a tool that enables high-throughput quantification of both conformational specificity and binding affinity of protein-DNA interactions. Our approach is to combine quantitative detection of DNA conformational change and protein-DNA binding in a DNA microarray format. The DNA conformational change is measured by spectral self-interference fluorescence microscopy that determines surface-immobilized DNA conformation by measuring axial height offluorophores tagged to specific nucleotides. The amount of bound protein and DNA are measured by white light reflectance spectroscopy that quantifies molecular surface densities by measuring bioniolecule layer thicknesses. By implementing a dual-spectral imaging configuration, we can perform the two independent interferometric measurements in parallel using two separate spectral bandwidths. [TRUNCATED