Plasmonic structures for enhancement of semiconductor infrared detectors.

Plazmonika je jedna od oblasti nauke koje se u današnje vreme eksplozivno razvijaju. Ona je posvecena elektromagnetici nanokompozitnih metamaterijala koji podržavaju rezonanciju površinskih plazmona polaritona (surface plasmons polaritons, SPP). SPP predstavljaju hibridne ekscitacije nastale sprezanjem elektromagnetnih talasa sa oscilacijama slobodnih nosilaca naelektrisanja na razdvojnim površima izmeðu dva materijala sa razlicitim znakovima relativne dielektricne permitivnosti, npr. provodnika i dielektrika. Posledica ovakvog sprezanja je izmeðu ostalog lokalizacija elektromagnetnog zracenja na podtalasnom nivou, osobina plazmonskih struktura koja je našla veliku primenu u spektroskopiji, integrisanoj optici, senzorici itd. Jedna od znacajnih primena plazmonske lokalizacije je u oblasti u fotodetekcije, pre svega za poboljšanje performansi solarnih celija. Najveci problem proširenja primene plazmonike u fotodetekciji na drugu oblast od interesa, infracrvene (IC) detektore, predstavlja cinjenica da je plazmonska ucestanost vecine provodnika (metala) u ultraljubicastom ili vidljivom delu spektra. Brojne tehnološki pogodne tehnike koje su dale izuzetne rezultate za poboljšanje solarnih celija ostale su zbog toga bez primene u IC oblasti. Ova disertacija se prevashodno bavi proširenjem primenljivosti plazmonike na srednjetalasnu i dugotalasnu infracrvenu oblast i metodama prevazilaženja ogranicenja koje postavljaju sami materijali. U tu svrhu razmatrana su dva pristupa. Jedan od njih podrazumeva upotrebu submikrometarskih cestica od provodnog materijala. Funkcionalnost u IC oblasti postiže se kombinacijom izbora pogodnijeg materijala cestica (elektroprovodni opticki providni oksid umesto metala) i imerzije cestica u dielektrik visokog indeksa prelamanja. Drugi pristup podrazumeva korišcenje tankih metalnih slojeva sa ureðenom matricom apertura koji omogucuju pomeranje spektralne zavisnosti prema crvenom delu spektra menjanjem iskljucivo geometrijskih parametara matrice apertura. Oba pristupa nude mogucnost prakticno proizvoljnog podešavanja frekvencije plazmonske rezonancije i time njenu upotrebu za IC detektore. Analiza ova dva pristupa raðena je numerickim simulacijama, primenom metode konacnih elemenata. Uticaj na performanse infracrvenih detektora odreðivan je kombinovanjem rezultata numerickih modelovanja sa analitickim modelom IC detektora...Plasmonics is one of the fastest growing fields in the contemporary science. Plasmonics studies properties of nanocomposite metamaterials which support surface plasmon polariton (SPP) resonance. SPP are formed by coupling electromagnetic waves with free charge carrier oscillations at an interface between materials with different signs of their relative permittivity i.e. conductor and dielectric. One of the results of this coupling is localization of electromagnetic radiation on subwavelength scale, property of plasmonic structures that has found practical use in the fields of spectroscopy, integrated optics, sensors, etc. One of the principal applications of light localization is in the field of photodetection, primarily for the enhancement of solar cells. The main problem with any attempt to apply plasmonics for photodetector enhancement at longer wavelengths, i.e. for infrared (IR) detectors, is that the plasmon resonance frequency of most conductive materials (metals) is in the ultraviolet or visible part of the spectrum. Because of this many convenient methods yielding excellent results for plasmonic enhancement of solar cells have not been utilized in the infrared. The main goal of this dissertation is bringing plasmonic enhancement of semiconductor photodetectors to medium and long wavelength infrared parts of the spectrum by overcoming limitations imposed by material properties. To achieve this two approaches are considered and analyzed. The first approach implies the use of submicrometer conductive particles. A sufficient shift of plasmonic resonance to the infrared is achieved by both a suitable choice of the particle material (transparent conductive oxides – TCO instead of metal) and by immersion of the particles in dielectric with a large index of refraction. The second approach is based on using thin metallic films with 2D array of holes drilled through them, where redshifting is achieved by tuning the geometrical properties of the hole array. It is shown that both approaches allow one to achieve practically arbitrary positioning of plasmonic resonance in the infrared. The finite element method was used for numerical simulations of the analyzed structures. A combination of the results of numerical modeling with the analytical results for the IR detectors was used to determine the effects of the plasmonic enhancement..

Plasmonic structures for enhancement of semiconductor infrared detectors.

Plazmonika je jedna od oblasti nauke koje se u današnje vreme eksplozivno razvijaju. Ona je posvecena elektromagnetici nanokompozitnih metamaterijala koji podržavaju rezonanciju površinskih plazmona polaritona (surface plasmons polaritons, SPP). SPP predstavljaju hibridne ekscitacije nastale sprezanjem elektromagnetnih talasa sa oscilacijama slobodnih nosilaca naelektrisanja na razdvojnim površima izmeðu dva materijala sa razlicitim znakovima relativne dielektricne permitivnosti, npr. provodnika i dielektrika. Posledica ovakvog sprezanja je izmeðu ostalog lokalizacija elektromagnetnog zracenja na podtalasnom nivou, osobina plazmonskih struktura koja je našla veliku primenu u spektroskopiji, integrisanoj optici, senzorici itd. Jedna od znacajnih primena plazmonske lokalizacije je u oblasti u fotodetekcije, pre svega za poboljšanje performansi solarnih celija. Najveci problem proširenja primene plazmonike u fotodetekciji na drugu oblast od interesa, infracrvene (IC) detektore, predstavlja cinjenica da je plazmonska ucestanost vecine provodnika (metala) u ultraljubicastom ili vidljivom delu spektra. Brojne tehnološki pogodne tehnike koje su dale izuzetne rezultate za poboljšanje solarnih celija ostale su zbog toga bez primene u IC oblasti. Ova disertacija se prevashodno bavi proširenjem primenljivosti plazmonike na srednjetalasnu i dugotalasnu infracrvenu oblast i metodama prevazilaženja ogranicenja koje postavljaju sami materijali. U tu svrhu razmatrana su dva pristupa. Jedan od njih podrazumeva upotrebu submikrometarskih cestica od provodnog materijala. Funkcionalnost u IC oblasti postiže se kombinacijom izbora pogodnijeg materijala cestica (elektroprovodni opticki providni oksid umesto metala) i imerzije cestica u dielektrik visokog indeksa prelamanja. Drugi pristup podrazumeva korišcenje tankih metalnih slojeva sa ureðenom matricom apertura koji omogucuju pomeranje spektralne zavisnosti prema crvenom delu spektra menjanjem iskljucivo geometrijskih parametara matrice apertura. Oba pristupa nude mogucnost prakticno proizvoljnog podešavanja frekvencije plazmonske rezonancije i time njenu upotrebu za IC detektore. Analiza ova dva pristupa raðena je numerickim simulacijama, primenom metode konacnih elemenata. Uticaj na performanse infracrvenih detektora odreðivan je kombinovanjem rezultata numerickih modelovanja sa analitickim modelom IC detektora...Plasmonics is one of the fastest growing fields in the contemporary science. Plasmonics studies properties of nanocomposite metamaterials which support surface plasmon polariton (SPP) resonance. SPP are formed by coupling electromagnetic waves with free charge carrier oscillations at an interface between materials with different signs of their relative permittivity i.e. conductor and dielectric. One of the results of this coupling is localization of electromagnetic radiation on subwavelength scale, property of plasmonic structures that has found practical use in the fields of spectroscopy, integrated optics, sensors, etc. One of the principal applications of light localization is in the field of photodetection, primarily for the enhancement of solar cells. The main problem with any attempt to apply plasmonics for photodetector enhancement at longer wavelengths, i.e. for infrared (IR) detectors, is that the plasmon resonance frequency of most conductive materials (metals) is in the ultraviolet or visible part of the spectrum. Because of this many convenient methods yielding excellent results for plasmonic enhancement of solar cells have not been utilized in the infrared. The main goal of this dissertation is bringing plasmonic enhancement of semiconductor photodetectors to medium and long wavelength infrared parts of the spectrum by overcoming limitations imposed by material properties. To achieve this two approaches are considered and analyzed. The first approach implies the use of submicrometer conductive particles. A sufficient shift of plasmonic resonance to the infrared is achieved by both a suitable choice of the particle material (transparent conductive oxides – TCO instead of metal) and by immersion of the particles in dielectric with a large index of refraction. The second approach is based on using thin metallic films with 2D array of holes drilled through them, where redshifting is achieved by tuning the geometrical properties of the hole array. It is shown that both approaches allow one to achieve practically arbitrary positioning of plasmonic resonance in the infrared. The finite element method was used for numerical simulations of the analyzed structures. A combination of the results of numerical modeling with the analytical results for the IR detectors was used to determine the effects of the plasmonic enhancement..

Bio-Inspired Nanomembranes as Building Blocks for Nanophotonics, Plasmonics and Metamaterials

Nanomembranes are the most widespread building block of life, as they encompass cell and organelle walls. Their synthetic counterparts can be described as freestanding or free-floating structures thinner than 100 nm, down to monatomic/monomolecular thickness and with giant lateral aspect ratios. The structural confinement to quasi-2D sheets causes a multitude of unexpected and often counterintuitive properties. This has resulted in synthetic nanomembranes transiting from a mere scientific curiosity to a position where novel applications are emerging at an ever-accelerating pace. Among wide fields where their use has proven itself most fruitful are nano-optics and nanophotonics. However, the authors are unaware of a review covering the nanomembrane use in these important fields. Here, we present an attempt to survey the state of the art of nanomembranes in nanophotonics, including photonic crystals, plasmonics, metasurfaces, and nanoantennas, with an accent on some advancements that appeared within the last few years. Unlimited by the Nature toolbox, we can utilize a practically infinite number of available materials and methods and reach numerous properties not met in biological membranes. Thus, nanomembranes in nano-optics can be described as real metastructures, exceeding the known materials and opening pathways to a wide variety of novel functionalities

Brochosome-Inspired Metal-Containing Particles as Biomimetic Building Blocks for Nanoplasmonics: Conceptual Generalizations

Recently, biological nanostructures became an important source of inspiration for plasmonics, with many described implementations and proposed applications. Among them are brochosome-inspired plasmonic microstructures—roughly spherical core-shell particles with submicrometer diameters and with indented surfaces. Our intention was to start from the nanoplasmonic point of view and to systematically classify possible alternative forms of brochosome-inspired metal-containing particles producible by the state-of-the-art nanofabrication. A wealth of novel structures arises from this systematization of bioinspired metal-containing nanocomposites. Besides various surface nanoapertures, we consider structures closely related to them in electromagnetic sense like surface nano-protrusions, shell reliefs obtained by nano-sculpting, and various combinations of these. This approach helped us build a new design toolbox for brochosome-inspired structures. Additionally, we used the finite elements method to simulate the optical properties of simple brochosome-inspired structures. We encountered a plethora of advantageous optical traits, including enhanced absorption, antireflective properties, and metamaterial behavior (effective refractive index close to zero or negative). We conclude that the presented approach offers a wealth of traits useful for practical applications. The described research represents our attempt to outline a possible roadmap for further development of bioinspired nanoplasmonic particles and to offer a source of ideas and directions for future research

Plasmonic structures for enhancement of semiconductor infrared detectors.

Plazmonika je jedna od oblasti nauke koje se u današnje vreme eksplozivno razvijaju. Ona je posvecena elektromagnetici nanokompozitnih metamaterijala koji podržavaju rezonanciju površinskih plazmona polaritona (surface plasmons polaritons, SPP). SPP predstavljaju hibridne ekscitacije nastale sprezanjem elektromagnetnih talasa sa oscilacijama slobodnih nosilaca naelektrisanja na razdvojnim površima izmeðu dva materijala sa razlicitim znakovima relativne dielektricne permitivnosti, npr. provodnika i dielektrika. Posledica ovakvog sprezanja je izmeðu ostalog lokalizacija elektromagnetnog zracenja na podtalasnom nivou, osobina plazmonskih struktura koja je našla veliku primenu u spektroskopiji, integrisanoj optici, senzorici itd. Jedna od znacajnih primena plazmonske lokalizacije je u oblasti u fotodetekcije, pre svega za poboljšanje performansi solarnih celija. Najveci problem proširenja primene plazmonike u fotodetekciji na drugu oblast od interesa, infracrvene (IC) detektore, predstavlja cinjenica da je plazmonska ucestanost vecine provodnika (metala) u ultraljubicastom ili vidljivom delu spektra. Brojne tehnološki pogodne tehnike koje su dale izuzetne rezultate za poboljšanje solarnih celija ostale su zbog toga bez primene u IC oblasti. Ova disertacija se prevashodno bavi proširenjem primenljivosti plazmonike na srednjetalasnu i dugotalasnu infracrvenu oblast i metodama prevazilaženja ogranicenja koje postavljaju sami materijali. U tu svrhu razmatrana su dva pristupa. Jedan od njih podrazumeva upotrebu submikrometarskih cestica od provodnog materijala. Funkcionalnost u IC oblasti postiže se kombinacijom izbora pogodnijeg materijala cestica (elektroprovodni opticki providni oksid umesto metala) i imerzije cestica u dielektrik visokog indeksa prelamanja. Drugi pristup podrazumeva korišcenje tankih metalnih slojeva sa ureðenom matricom apertura koji omogucuju pomeranje spektralne zavisnosti prema crvenom delu spektra menjanjem iskljucivo geometrijskih parametara matrice apertura. Oba pristupa nude mogucnost prakticno proizvoljnog podešavanja frekvencije plazmonske rezonancije i time njenu upotrebu za IC detektore. Analiza ova dva pristupa raðena je numerickim simulacijama, primenom metode konacnih elemenata. Uticaj na performanse infracrvenih detektora odreðivan je kombinovanjem rezultata numerickih modelovanja sa analitickim modelom IC detektora...Plasmonics is one of the fastest growing fields in the contemporary science. Plasmonics studies properties of nanocomposite metamaterials which support surface plasmon polariton (SPP) resonance. SPP are formed by coupling electromagnetic waves with free charge carrier oscillations at an interface between materials with different signs of their relative permittivity i.e. conductor and dielectric. One of the results of this coupling is localization of electromagnetic radiation on subwavelength scale, property of plasmonic structures that has found practical use in the fields of spectroscopy, integrated optics, sensors, etc. One of the principal applications of light localization is in the field of photodetection, primarily for the enhancement of solar cells. The main problem with any attempt to apply plasmonics for photodetector enhancement at longer wavelengths, i.e. for infrared (IR) detectors, is that the plasmon resonance frequency of most conductive materials (metals) is in the ultraviolet or visible part of the spectrum. Because of this many convenient methods yielding excellent results for plasmonic enhancement of solar cells have not been utilized in the infrared. The main goal of this dissertation is bringing plasmonic enhancement of semiconductor photodetectors to medium and long wavelength infrared parts of the spectrum by overcoming limitations imposed by material properties. To achieve this two approaches are considered and analyzed. The first approach implies the use of submicrometer conductive particles. A sufficient shift of plasmonic resonance to the infrared is achieved by both a suitable choice of the particle material (transparent conductive oxides – TCO instead of metal) and by immersion of the particles in dielectric with a large index of refraction. The second approach is based on using thin metallic films with 2D array of holes drilled through them, where redshifting is achieved by tuning the geometrical properties of the hole array. It is shown that both approaches allow one to achieve practically arbitrary positioning of plasmonic resonance in the infrared. The finite element method was used for numerical simulations of the analyzed structures. A combination of the results of numerical modeling with the analytical results for the IR detectors was used to determine the effects of the plasmonic enhancement..

Super Unit Cells in Aperture-Based Metamaterials

An important class of electromagnetic metamaterials are aperture-based metasurfaces. Examples include extraordinary optical transmission arrays and double fishnets with negative refractive index. We analyze a generalization of such metamaterials where a simple aperture is now replaced by a compound object formed by superposition of two or more primitive objects (e.g., rectangles, circles, and ellipses). Thus obtained "super unit cell" shows far richer behavior than the subobjects that comprise it. We show that nonlocalities introduced by overlapping simple subobjects can be used to produce large deviations of spectral dispersion even for small additive modifications of the basic geometry. Technologically, some super cellsmay be fabricated by simple spatial shifting of the existing photolithographic masks. In our investigation we applied analytical calculations and ab initio finite element modeling to prove the possibility to tailor the dispersion including resonances for plasmonic nanocomposites by adjusting the local geometry and exploiting localized interactions at a subwavelength level. Any desired form could be defined using simple primitive objects, making the situation a geometrical analog of the case of series expansion of a function. Thus an additional degree of tunability of metamaterials is obtained. The obtained designer structures can be applied in different fields like waveguiding and sensing

Plasmonic enhancement of light trapping in photodetectors

We consider the possibility to use plasmonics to enhance light trapping in such semiconductor detectors as solar cells and infrared detectors for night vision. Plasmonic structures can transform propagating electromagnetic waves into evanescent waves with the local density of states vastly increased within subwavelength volumes compared to the free space, thus surpassing the conventional methods for photon management. We show how one may utilize plasmonic nanoparticles both to squeeze the optical field into the active region and to increase the optical path by Mie scattering, apply ordered plasmonic nanocomposites (subwavelength plasmonic crystals or plasmonic metamaterials), or design nanoantennas to maximize absorption within the detector. We show that many approaches used for solar cells can be also utilized in infrared range if different redshifting strategies are applied

PLASMONIC ENHANCEMENT OF LIGHT TRAPPING IN PHOTODETECTORS

We consider the possibility to use plasmonics to enhance light trapping in such semiconductor detectors as solar cells and infrared detectors for night vision. Plasmonic structures can transform propagating electromagnetic waves into evanescent waves with the local density of states vastly increased within subwavelength volumes compared to the free space, thus surpassing the conventional methods for photon management. We show how one may utilize plasmonic nanoparticles both to squeeze the optical field into the active region and to increase the optical path by Mie scattering, apply ordered plasmonic nanocomposites (subwavelength plasmonic crystals or plasmonic metamaterials), or design nanoantennas to maximize absorption within the detector. We show that many approaches used for solar cells can be also utilized in infrared range if different redshifting strategies are applied

Analysis of acoustic cloaks for anti-sonar camouflage based on local resonance in acoustic metamaterials

Non-visual camouflage plays a significant role in the art of military deception. One of the fields of interest is auditory camouflage, where the goal is to remove the acoustic signature of an object, whether it is generated by the object itself or scattered from a surveillance device like sonar. A recently proposed approach to auditory camouflage is acoustic cloaking, where the object is made 'invisible' in acoustic sense by surrounding it with a cloak of acoustic metamaterial. Acoustic metamaterial is basically an artificial structure tailored to enable control of acoustic wave dispersion through Bragg scattering, where the features of the structure have subwavelength dimensions. The operation of an acoustic cloak is based on negative effective dynamic mass and bulk modulus which can be obtained by local resonances. This leads to a possibility to fully tailor the path of acoustic waves (infrasound, audible waves or ultrasound) around the camouflaged object, effectively enabling one to make waves avoid the object and render it invisible. In this contribution we perform a full finite element modeling of the elements of an acoustic cloak, analyze it and consider coordinate transformation necessary to ensure acoustic concealment of a macroscopic object. We investigated spatial distribution of acoustic waves for two different scatterers, one of them being a cylindrical object with circular basis, another one a cylinder with elliptical basis. All our calculations were performed for a realistic sea water medium, modeled by an empirical formula. We considered the frequency dispersion of the acoustic field in different spectral ranges, from infrasound to audible frequencies. For elliptic cloaks we applied a very simple approach that nevertheless furnished better acoustic cloaking than some more complex layered profiles previously published

Subwavelength nickel-copper multilayers as an alternative plasmonic material

In this contribution we consider numerically and experimentally the use of bimetallic superlattices, i.e. allmetal plasmonic crystals consisting of two alternating materials with negative values of their relative dielectric permittivities. We use the copper-nickel multilayers. Copper is a good plasmonic material, but not widely used due to surface oxidation impairing its electromagnetic properties over time. The layers of nickel, also a plasmonic material, serve a dual purpose of being a protection against copper oxidation and ensuring formation of surface waves at the alternating interfaces between the two materials. At the same time, the multilayers serve as couplers between the propagating and the surface waves.[http://www.photonica.ac.rs/2017/