APPLICATION OF PHOTONICS

SUBMITTED TO :Dr. A KASI VISHWANATHREADER, CENTRE FOR NANOSCIENCE AND TECHNOLOGY

DEVIKA LAISHRAM

CONTENTS WHAT IS PHOTONICS NEED TO STUDY PHOTONICS NANOSCALE QUANTUM OPTICS ALL OPTICAL ROUTING PLASMONICS FOR ENHANCED MAGNETIC STORAGE DIAGNOSIS,THERAPY AND DRUG DELIVERY USING LIGHT NANOSCALE IMAGING CHEMICAL AND BIOLOGICAL SENSORS AT MOLECULAR SCALE NANOTAGGING MANIPULATION OF LIGHT DISTRIBUTION SELF ASSEMBLY OF NANOPARTICLES NANOPHOTONIC MATERIALS WITH TAILORED OPTICAL PROPERTIES GRAPHENE PHOTONICS NANOPHOTONICS ON A CHIP INTEGRATION WITH ELETRICAL CIRCUITS BIODERIVED PHOTOMATERIAL NANOPHOTONICS FOR MEDICINE AND BIOTECHNOLOGY PEBBLE AND NANOCLINICS FUTURE OUTLOOK

What is photonics ???• Photonics is the interaction of light with matter. It is the

technology of light.• “The science and engineering of light-matter interactions

that take place on wavelength and sub wavelength scales where the physical, chemical, or structural nature of natural or artificial nanostructure matter controls the interactions”.

• Optical fibers and waveguides , semiconductor physics , LEDs , laser diodes, photodiodes, avalanche diodes, organic photonic devices , photonic crystal fibers and many other devices are based on interactions between light and matter.

• Photonics began in 1960s with invention of laser and laser diode and optical fibers and Erbium doped fiber amplifiers in 1970s. Earlier applications of photonics were devoted to telecommunications.

The need to study applications of photonics???

• Vital role in reducing energy consumption (lighting, building high speed internet systems & developing novel biomedical sensors).

• At nanoscale, optical phenomena is exploited to challenge existing technological limits and help deliver superior photonic devices.

• Nanophotonics concerns building, manipulating and characterizing optically active nanostructures to create new capabilities in instrumentation for nanoscale, chemical and biomedical sensing, information and communications technologies, enhanced solar cells and lighting, disease treatment, environmental remediation, etc.

• Over the next ten years nanophotonic structures and devices promise dramatic reductions in energies of device operation, densely integrated information systems with lower power dissipation, enhanced spatial resolution for imaging and patterning, and new sensors of increased sensitivity and specificity

• Encompassing areas such as metamaterials , plasmonics, quantum nanophotonics and functional photonic materials, nanophotonics is perceived as a basic research field.

Nanoscale Quantum Optics• Applications include nanoscale light sources, faster non

classical information processing.• Q-informatics transport and process Q-information and

Q-optics provides the basis for optical Q-bits (a quantum state used for information processing).

• Nanoscale Q-optics will allow implementation on-chip of existing concepts and emergence of novel phenomena.

• Q-dot excited states entangled with photon states in photonic crystal cavities resulting in scalable, coupled optical q-bits.

• Emission of single quantum emitters has been manipulated and directed with plasmonic nanoantennas.

• Control of emission with nanostructures provides new sources for q-optics and improve properties of more conventional solid state LEDs and vertical cavity surface emitting lasers.

• Control of optical logic with single quantum systems open new avenues for q-information and applications in security and cryptography.

• Nanoscale control of light emission with highly spatially structured fields would allow the violation of conventional quantum selection rules for absorption and emission offering new prospects for applications.

ALL OPTICAL ROUTING

• Application includes all optical signal processing transparent optical networks.

• To harness full bandwidth of optical and data communications and overcome the bandwidth limitation of electronic components it is imperative to minimize optical-electrical/electrical-optical conversion of information.

• Processing of optical information by all optical means allows the full available bandwidth to be exploited and to reduce the energy loss.

• Nanophotonics improves all optical signal processing and decrease the on chip footprint of the individual components.

• It shows engineering of the light matter interactions required to achieve all optical signal processing

• Increasing the strength of those interactions minimises the required output intensity of the controlling light source to obtain a desired functionality.

3 distincts routes exist to obtain desired light matter interactions.• Ultralow nanophotonic resonators have on chip

footprint of roughly a wavelength squared and the resonant nature of the structure reduces the index change required to switch the light.

• Slow light in photonic or plasmonic structures has an enhanced light matter interaction,allows ultrasmall add/drop filters to be fabricated, slow light needs to balance the slowdown factor with bandwidth Kramers-Kronig relations.

• Plasmonic structures allow non linear processes to be greatly enhanced due to achievable electric field enhanacements, enhancing second and third order optical non linearities and thus controlling light with light in plasmonic waveguides,plasmonic crystals and using metamaterials to achieve switching below 1 ps timescale in few 100 nm size devices,plasmonics has high inherent bandwidth.

Plasmonics for enhanced magnetic storage • For high speed read/write and high

density data storage.• To improve writeability the medium is

heated to lower the switching field of high anosotropic small grain media.

• After the media is written it cools for long term storage.

• The size of region to be heated is below diffraction limit and use near field device like nanophotonic antenna (Au,Cu,Ag) with size and shape optimised for creation of surface plasmons.

• Plasmonic antennas having high writing speed has densities upto 1 Tb/sq.inch.

• A resonant antenna structure(spehere or rod shaped) is combined with optical notch which concentrates the incident optical field.

Recent improvements in track width and optical efficiecny were obtained using antennas with advantageous near-optical effects on pattererned media

Diagnosis,therapy and drug delivery using light• Plasmon-based cancer therapy where nanoscale noble metal nanoparticles are used

for targeted destruction of tumour tissue.• It is due to combinaton of surface chemistry – finding the malignant tissue leading

to aggregate of the particlse around the tumour and careful design of the optical properties of nanoparticles.

• Resonant light absorption of the particle occurs in a spectral regime (near-infrared) where human tissue is transparent leading to heat induced apoptosis of the malignant tissue.

• Mutli shell particles including magnetic layers would allow for their use as contrast reagents for magnetic resonance imaging leading to THERANOSTICS where the same nanophotonic unit(multi shell nanoparticle) is used both for diagnosing and treating malignant tumour.

• Light induced drug release – opening of cages delivering the drug lies in exploitation of changes in conformation of complex biomloecules induced by UV, challenge is improving response of molecular systems to lower energy radiation by limiting harmful side effects on cells in the immediate vicinity of illumination spot.

• Combining with microfluidic circuits, nanoplasmonic sensing opens new opportunities to develop novel analytical platforms to detect, from singe drop of blood, diseases such as cancer at an earlier stage and perform treatment monitoring.

Nanoscale imaging: biological and single imaging inspection tools for nanofabrication and quality control biological/cell tags.

• Super resolution techniques surpass the diffraction limit for visible light and allow researchers to resolve objects at nanometre scale

• It relies on high NA lenses and far field operation where the point spread function is engineered to break diffraction limit.

• Stimulated emission depletion (STED) is used for nanoscale biological imaging and in technical inspection and quality control in nanofabrication.

• Super resolution depends on detection of luminiscent labels like dye labels and fluorescent proteins ,controlled tagging of cells and quantum dots for in vitro biomedical studies.

• Optical nanoantenna images single molecules in high concentration ,operating at 25 nm scale gives improved sensitivity and specificity for wide range of inspection purposes.

• Tip enhanced scanning microscopy’s scalability in frequency , allows nanoscale imaging with wavelength of choice to manipulate specific resonance of material system

Chemical & Biological sensors at the molecular scale Applications include disease diagnosis, treatment monitoring, mobile sensors, monitoring pollution in water and soil ,monitoring chemical exposure,detection of pathogens in food products.

• Nanophotonics are use as transducer in biochemical sensors exploiting concepts of optical antennas and surface enhanced Raman spectroscopy,surface plasmon resonance and surface enhanced mid infrared absorption spectroscopy

• Sensitivity of nanaphotonic sensors is characterized by figure of merit, defined as a shift compared to the width in surface plasmon resonance.

• FOM reach 10 for sensors based on isolated plasmonic particles and about 50 for sensors based on extended metallic fil supporting surface plasmon polaritons(SPP).

• Nanophotonics sensing sites show electromagnetic field enhancement in a narrow spectral range.

• Design of sensing sites showing field enhancement would enable molecular fingerprinting of complex molecules via interrogation of their rotational, vibrational and electronic resonances on same sensing site and allow simultaneous multispectral imaging of different molecular species.

Nano Tagging : anti counterfeiting,food safety tags and medical diagnostics

• Arrays of nanoscale optical resonators and metamaterials allow the creation of novel optical responses like negative refraction,highly enhanced light scattering in spectrally narrow windows, nanoscale bar codes and microscale radio frequency active tags.

• A major challenge is in development of suitable fabrication strategies applicable to flexible substrates.

• Patterning of materials like organic layers - organic metamaterials might allow knowledge transfer from the area of plastic electronics in order to create cheap tags on flexible substrates amenable to planar or solution processing.

• Non contact high capacity nanophotonics tagging for bio medical based assays based on use of nanostructured barcodes is a new technique.

• High encoding capacity along with the applicability of the manufactured bar codes to multiplexed assays allows accurate measurement of variety of molecular interactions leading to new opportunities in genomics, proteomics high throughput screening and medical diagnostics.

Manipulation of Light Distribution at the Nanoscale• Applications include :

1. Light generation,

2. Light harvesting ,

3. High efficiency and high colour purity phosphors

4. Polarised colour-converters for LED TVs and backlighting.

• Nanostructures induce strong modification of light emission kinetics in luminescent materials.

• Light materials emission can be suitably controlled for increased emission efficiency spatial manipulation, angular distribution, polarisation, spectral linewidth .

• Emission kinetics can be modified by exciton plasmon coupling; metallic nanostructures provide localised plasmons with resonances tuned by the material, shape and size and act as optical nanoantennas in close proximity of emitters.

• Quantum confined emitters are place in close proximity with proper spectral matching for nonradiative energy transfer from donor to acceptor(between Q-dots or between nanowires and crystals). Non radiative mechanism is to control excitation energy flow.

• Strongly coupled exciton-photon systems can radically change the emission and lasing properties of devices. These devices have shown Bose-Einstein condensation and room temperature polariton lasing.

• For emitting devices like LEDs the emission at grazing incidence beyond critical angle is trapped in the device or coupled in a tp guided layer , resulting in narrow escape cone for the emitted light.

Self assembly of Nanoparticles• Applications include

1. Heterogeneous integration

2. Opto-biotechnology

3. Environmental sensors

4. Medical sensors

5. Artificial nano scale materials

6. Bio-circuits

7. Artificial and organs

8. Energy harvesting

• Self assembly techniques or bottom up nanostructures offers an alternative to top-down methods like e-beam lithography nad interference lithography.

• Bottom up techniques such as DNA or protein linked metal nanoparticles have succeded in manufacturing dimers, trimers or more complex nano particle oligomers.

Nanophotonic materials with tailored optical properties

• By nanostructuring new nanophotonic materials with exceptional optical properties can be crafted : nano arrays with extra ordinary transmission, perfect absorbers, switchable and tuneable materials, media with huge non linear response, novel polarising elements and even negative refractive materials.

Graphene photonics

• Applications include solar cells ,LEDs, touch screens, photodetectors, ultrafast lasers.

• Grapehene is a novel material combining both optical and electronic properties.

• The carrier density in graphene can be controlled by applying an external voltage such that the electromagnetic reaction results in a tuneable spectral response.

• Grapehene will add electro-optical capability to metamaterials especially in IR and tetra hertz domain.

• By proper tuning, graphene offers the potential of larger field enhancement than in the case of metals.

Nanophotonics on a Chip

IBM vision of silicon photonics for optical interconnects in future electronics

• Future electronics will rely on nanophotonics for transmitting information across the chip.

• This will enable the electronics industry to continue scaling in size and bandwidth without the existing limitations in power.

• The optical elements are required to be compatible with silicon, the material of choice for electronics, i.e, silicon nanophotonics.

• Light amplification and emission can be achieved by using silicon as a nonlinear optical material as refractive index for silicon is very high, and extremely compact waveguides can be created that confine light very tightly .

• This results in the ability of the devices to operate at very low power levels.

Integration with Electronic Circuits for Ultrasmall, Ultrahigh-speed Information Communications

Applications

SEM image of a Si-based ring resonator coupled to a waveguide. Inset shows the entire ring structure (Alameda 2004).

• With rapid advances in CMOS and CMOS-compatible processing techniques Si-based device like coupled resonator-waveguide have started to gain popularity, despite the indirect gap nature of Si (Hogan 2010).

• Ultrasmall dimensioned lasers utilizing semiconductor or metal materials can provide highly efficient optical sources that can be readily integrated on-chip.

Bioderived photonic material• The green fluorescent protein and its variants exhibit strong

emission that can be generated by both one-photon and two-photon excitations.

• By choosing an appropriate variant, one can select the excitation and the emission wavelength.

• The optical properties of these proteins are very much dependent on their nanostructures (Yang et al., 1996; Prasad, 2003).

• GFP has extensively been used as biological fluorescent markers for in vivo imaging and fluorescence resonance energy transfer (FRET)imaging to study protein–protein and DNA–protein interactions.

Bacteriorhodopsin.

• Naturally occurring protein for which a broad range of photonic applications

• Its robustness, ease of processing into optical quality films is suitable photophysics and photochemistry of the excited state, and flexibility for chemical and genetic modifications make this protein of significant interest for photonic applications (Birge et al., 1999).

• These applications include random access thin film memories , photon counters and photovoltaic converters , spatial light modulators, reversible holographic media, artificial retinas , two-photon volumetric memories and pattern recognition systems.

DNA

• Naturally occurring DNA exhibits a number of properties useful for photonics.

• The constituent nucleotide building blocks of DNA (involving heterocyclic ring bases) are optically transparent (nonabsorbing) over a wider spectral range, from 350 nm to 1700 nm.

• Their specificity in hybridization (selectivity in base pairing to form double strand) and their ability to bind on their surface through electrostatic attraction ( DNA being negatively charged), or intercalate within the double strand, allows them to incorporate various photonic active structural units.

• Their dielectric properties are suitable for them to be used as cladding layer for polymer electro-optic devices.

Nanophotonics for Biotechnologyand Nanomedicine

• Nanophotonics enables one to use optical techniques for tracking of drug intake elucidating its cellular pathway and monitoring subsequent intracellular interactions.

• For this purpose, bioimaging, biosensing, and single-cell biofunction studies, using optical probes, are proving to be extremely valuable.

• In the area of nanomedicine-based molecular recognition of diseases, light-guided and light-activated therapies provide a major advancement.

• Nanoparticles containing optical probes, light-activated therapeutic agents, and specific carrier groups directs the nanoparticles to the diseased cells or tissues, provide targeted drug delivery, with an opportunity for real-time monitoring of drug efficacy.

PEBBLE Nanosensors for In Vitro Bioanalysis

• A probe encapsulated by biologically localized embedding (PEBBLE), introduced by Kopelman and co-workers enables optical measurement of changes in intracellular calcium levels, pH, and other biologically significant chemicals.

• It provides a major advancement in the field of nanoprobes and nanomedicine.

• PEBBLEs are nanoscale spherical devices, consisting of sensor molecules entrapped in a chemically inert matrix.

• An example of a PEBBLE nanosensor is the calcium PEBBLE that utilizes calcium Green–1 and sulforhodamine dyes as sensing components.

• the PEBBLE technology offers the following benefits:

- It protects the cells from any toxicity associated with the sensing dye.

- It provides an opportunity to combine multiple sensing components (dyes , ionphores ) and create complex sensing schemes.

- It insulates the indicator dyes from cellular interferences such as protein binding.

NANOCLINICS FOR OPTICAL DIAGNOSTICS ANDTARGETED THERAPY

Illustrated representation of a nanoclinic.

• Nanoclinics have a complex surface functionalized silica nanoshell containing various probes for diagnostics and drugs for targeted delivery. It provide a new dimension to targeted diagnostics and therapy.

• They are produced using multistep nanochemistry in a reverse micelle nanoreactor and surface functionalized with known biotargeting agents.

• Nanoclinics are ~30-nm silica shells that can encapsulate various optical, magnetic, or electrical probes and externally activatable therapeutic agents.

• The size of these nanoclincs is small enough for them to enter the cell, in order for them to function from within the cell.

• Through the development of nanoclinics, new therapeutic approaches to disease can be accomplished from within the cell.

FUTURE OUTLOOK

POWER GENERATION AND CONVERSION• utilizing inorganic:organic hybrid nanostructures and nanocomposites can produce

broadband harvesting of solar energy while using flexible low-cost, large-area roll-to-roll plastic solar panels and solar tents.

• rare-earth-doped nanoparticle up-converters and quantum cutters. can be utilized to harvest solar photons at the edges of solar spectrum specifically in the IR and in the deep UV.

• for lighting applications especially in mercury-free efficient lighting sources, display and security, quantum-cutter nanoparticles can be utilized.

INFORMATION TECHNOLOGY• society has to deal with the rapid increase of information and the need to store,

display, and disseminate it, increased processing speed, increased bandwidth (more channels to transmit information), high-density storage, and highresolution, flexible thin displays are going to demand new technological innovations.

• wireless communications, coupling of photonics to RF/microwave will play a major role in future information technology.

• Photonic crystal-based integrated photonic circuits, as well as hybrid nanocomposite-based display devices and RF/photonic links, are some specific examples

SENSOR TECHNOLOGY• There is an ever-increasing need to enhance the capability of sensor technology for

health, structural, and environmental monitoring. • new strains of microbial organisms and the spread of infectious diseases that

require rapid detection and identification. This requires point detection as well as environmental monitoring.

• Another area of major concern, worldwide, is the threat ofchemical and biological terrorism. The detection not only for danger posed to health, through chemical and biological agents, but for structural damage.

• Nanophotonics-based sensors utilizing nanostructured multiple probes provide the ability for simultaneous detection of many threats, as well as the ability for remote sensing where necessary.

NANOMEDICINE• Nanomedicine utilizing light-guided and light-activated therapy, with ability to

monitor real-time drug action, will lead to new approaches for more effective and personalized molecular-based therapy.

• A major concern already raised by many is any long-term adverse health effects (such as toxicity, accumulation in vital organs, obstruction of circulatory system, etc.) produced by nanoparticles.

REFERENCES• Nanophotonics European Association foresight

report june 2011.• Nanophotonics by Paras N Prasad• Applications: Nanophotonics and Plasmonics

by Evelyn L. Hu, Mark Brongersma, Adra Baca32 • Nanophotonics: Interactions, Materials, and

Applications by Yuzhen Shen, Christopher S. Friend, Yan Jiang, Daniel Jakubczyk, Jacek Swiatkiewicz, and Paras N. Prasad*

THANK YOU