We describe state-of-the-art optical communication subsystems that leverage advances in optical components based on microphotonic integrated circuits. The optical ICs are based on nanoengineered polymeric materials with optimal optical, electrical, mechanical, and thermal properties. Photonic components based on these polymeric chips have met all performance and reliability requirements in the telecommunication industry, and passed Telcordia GR-1209 and GR-1221 qualification. Subsystems based on these components, such as variable multiplexers (VMUX) and reconfigurable optical add/drop multiplexers (ROADM), have met the requirements of Telcordia GR-1312 and GR-63, and are deployed in optical networks.

The exploitation of nanotechnology from proof of principle to realizable commercial applications encounters considerable challenges in regards to high volume, large scale, low cost manufacturability and social ethics. This has led to concerns over converting powerful intellectual property into realizable, industry attractive technologies. At The Technology Partnership we specifically address the issue of successful integration of nanophotonics into industry in markets such as biomedical, ophthalmic, energy, telecommunications, and packaging. In this paper we draw on a few examples where we have either developed industrial scale nanophotonic technology or engineering platforms which may be used to fortify nano/microphotonic technologies and enhance their commercial viability.

Recent important advances in subwavelength nanostructures offer extraordinary control over the properties of light. We can now manipulate the propagation, storage, and generation of light, as well as practically prescribe light-matter interaction based on first-principles. Photonic crystals, in particular, offer the unique ability for arbitrary control of dispersion as well as ultrahigh quality factor (Q) and modal volume (V_m) nanocavities. In this talk, we will present, to our knowledge, the first near-field experimental observations of near-infrared subwavelength imaging in negative refraction photonic crystals, as well as discuss our efforts in enhanced nonlinearities in photonic crystal nanocavities.

We present on the design, fabrication and integration of micro/nano-scale photonic crystal devices and plasmonic optical devices for VLSI photonic integration application. Using photonic crystals, we design and fabricate nanoscale directional couplers, multimode interference devices, power splitters, wavelength splitters, triplexers, filters, and develop their integration and interconnection schemes and technology. Using plasmonic structures, we design and fabricate horizontal directional couplers, vertical directional couplers, and chirped grating plasmonic structures to generate subwavelength lightwaves to be focused onto nano-potonic devices and modules. We examine scientific and technological issues concerning the miniaturization, interconnection, and integration of these nano-scale photonic devices for applications toward functional VLSI integrated circuits and systems.

The polarization-dependent superprism phenomenon was demonstrated using holographic polymer-dispersed liquid crystal (HPDLC) films. The HPDLC film is designed and fabricated using three coplanar beams. The fabricated HPDLC film contained two-dimensional (2D) ordered nano-sized LC domains (~150nm in diameter) embedded in a polymer matrix; its periodicity was estimated using a scanning electron microscope to be ~350nm. The dispersion of white light from this HPDLC superprism was ~50°, and the deflection of light output from it was consistent with the theoretical value obtained by the plane wave expansion method.

This work addresses feature size effects (the lag-effect and roughness development) in chemically assisted ion beam etching (CAIBE) etching of InP based photonic crystals. Photonic crystal fields with varying hole size and periods were etched with different etching times. The slope of the etch depth versus diameter curves (lag-curves) reveals a hole size dependence, with a critical aspect ratio higher than 25. A model for the etch rate specific to Ar/Cl₂ CAIBE is proposed. We calculate the etch rate using a physico-chemical model which takes in to account the effect of Ar-ion sputtering and surface chemical reactions. In addition, it combines the aspect ratio dependence of the gas conductance of the etched holes. The origin and evolution of the bottom roughness of the etched holes is examined. The impact of the feature size dependence of the etching on the photonic crystal optical properties is then assessed by measuring the quality-factor of one dimensional Fabry Perot cavities using the Internal Light Source method, and discussed in terms of hole shape and depth. A systematic trend between the determined quality factor (Q) and the lag-effect is evidenced: Q decreases from about 250 to 60 when the hole depth drops from 5 μm to 2 μm.

Autocloning technique is an attractive deposition method to make photonic crystals since it can produce various photonic crystals by changing the substrate periodicity and the structure of the stacking materials. We report a novel method to fabricate autocloned photonic crystals. This method has better step-coverage, higher deposition rate and large deposition area than the sputtering method. We successfully preserved the periodic surface corrugation after the deposition of multilayer stacks by using an E-beam gun evaporation with ion-assisted deposition (IAD). Freedoms of the shaping process can be controlled by the power of IAD and the time of the ion source etching. The ion source etching is a physical etching process without any chemical reaction and dangerously reactive gas. The process parameters were described in this paper. During the deposition process, the refractive index can be adjusted by changing the deposition rate and the substrate temperature. The deposition rate was about 0.7~1 nm/s for SiO₂ which is almost ten times faster than the sputtering method. So this method is good for the mass production of photonic crystals.

A simple method for fabricating three-dimensional photonic crystals with all fourteen Bravais lattice structures and arbitrary lattice constant is proposed. The lattice structure is defined by three primitive translation vectors. The vectors form three triangles on the non-parallel three planes, which shape a tetrahedron, and a united two tetrahedrons forms a parallelepiped, which corresponds to a primitive cell of the lattice. All atoms lie at the vertexes of the parallelepiped where these three planes intersect. This means that all crystal lattices can be described by three sets of periodically aligned planes. The periodically aligned planes, or walls, can easily be fabricated by recording two-beam interference fringes in the recording material with a recording threshold such as a photoresist. Therefore, triple exposure of the twobeam interference fringes can create arbitrary crystal lattice structure. The optical arrangement of the practical interferometer is simplified when the angles between the normal to the recording plane and the three planes are equal. In this arrangement the triple exposure is followed subsequently by simply rotating the recording material around the normal to the recording plane. To create a lattice with arbitrary lattice plane with respect to a recording plane, two axes rotating stage must be used to rotate and tilt the recording plane. This method can create all fourteen Bravais lattices with arbitrary lattice constant while the conventional four-beam interference method creates only a limited number of lattice constants. Mathematical proof and numerical analysis results of this method are also shown.

Under the DARPA COMP-I (Compressive Optical MONTAGE Photography Initiative) program, the goal of this project is to significantly reduce the volume and form factor of infrared imaging systems without loss of resolution. The approach taken is to use an array of small lenses with extremely short focal lengths rather than the conventional approach of a single aperture lens system with large diameter and focal length. The array of lenses creates multiple copies of the scene on a single focal plane detector array, which are then used to reconstruct an image with resolution comparable to or higher than that of the conventional imaging system. This is achieved by a computational method known as super-resolution reconstruction. Work at the University of Delaware towards this end includes participation in the design and optimization of the optical system along with fabrication of some of the optical elements. Grayscale lithography using a high-energy beam sensitive (HEBS) glass photomask and proportional dry etch pattern transfer are the key techniques enabling the fabrication process. In this paper we will discuss the design of the imaging system while focusing on the fabrication aspects of the project.

Optical lithography is continually evolving to meet the ever demanding requirements of the micro - and nano- technology communities. Since the optical exposure systems used in lithography are some of the most advanced and complex optical instruments ever built, they involve ever more complex illuminator designs, nearly aberration free lenses, and hyper numerical apertures approaching unity and beyond. Fortunately, the lithography community has risen to the challenge by devising many inventive optical systems and various methods to use and optimize exposure systems. The recent advancement of water immersion technology into lithography for 193nm wavelengths has allowed the numerical aperture (NA) of lithographic lenses to exceed 1.0 or a hyper-NA region. This allows resolution limits to extend to the 45nm node and beyond with NA>1.3. At these extreme NAs, the imaging within the photoresist is accomplished by not only using water immersion but also using polarized light lithography. This paper will review the current state-of-the-art in immersion, hyper-NA lithography. We show the latest results and discuss the various phenomena that may arise using these systems. Furthermore, we show some of the advanced image optimization techniques that allow lithographic printing at the physical limits of resolution. In addition, we show that the future of optical lithography is likely to go well beyond the 30nm regime using advancements in 193nm double-patterning technology and/or the use of extreme ultra-violet (EUV) optical systems.

In this paper we demonstrate the design, fabrication, and characterization of a near-field photonic crystal nano-probe. By exploiting the ability of photonic crystals to strongly confine and guide light, we are able to produce optical spot sizes that are well below the diffraction limit. This offers in particular the advantage of higher resolution as compared to conventional optical probing techniques, while retaining the desirable features of speed, non-invasiveness, reliability, and low cost. Such a device has applications in scanning near-field optical microscopy (SNOM), nanolithography, high density optical data storage, and many other technologies. We describe the implementation of a photonic crystal device in the silicon-on-insulator (SOI) platform, as well as discuss progress being made in gallium-based alloys to further reduce the wavelength of operation and therefore the probe spot size.

This paper presents a novel fiber optic Fabry-Perot (FP) structure with a micrometric diameter tip. The fabrication of micro scale probes has become essential in intracellular surgery, in cell sensing, manipulation, and injection. It is of great importance in many fields, such as genetics, pathology, criminology, pharmacogenetics, and food safety. With such a tiny protrusion, the sensor can be inserted into micron size cells, say, for DNA analysis. With the FP cavity inside the fiber, the change of optical path difference (OPD) caused by the environment can be demodulated. In addition, the structure is intrinsically capable of temperature compensation. What's more, it is simple, cost-efficient, and compact. Last but not the least, the structure shows promise for nanometric protrusion. Once this goal is achieved, the sensor can be inserted into most cells. The sensor could pave the way for faster, more accurate medical diagnostic tests for countless conditions and may ultimately save lives by allowing earlier disease detection and intervention.

Traditional optical fibers have been developed to achieve novel characteristics for both macro- and micro-applications. Inorganic optical waveguides using two-dimensional photonic crystals and silicon-on-insulator technology are examples of recent trends for macro- and micro-scale optical applications, respectively. As bio-photonics devices operate mostly with visible light, visible-transparent materials such as metal oxides and polymers are preferred as the guiding medium. Although polymers have tremendous potential because of their enormous variation in optical, chemical and mechanical properties, their application for optical waveguides is limited by conventional lithography. We present a non-optical lithographic technique, called two-polymer microtransfer molding, to fabricate polymer nano-waveguides, on-chip light sources and couplers. Micro-sources using quantum dots emitting red light (625nm) are successfully embedded in a waveguides array as the on-chip light sources. Fabrication of a grating coupler is also attempted for various external light sources including lasers and white light. We have quantified propagation losses of the waveguides using CCD photometry. The guiding loss is approximately 1.7dB/mm. We also demonstrated that the surface roughness of the fabricated waveguides can be reduced by chemical etching. We demonstrate that low cost, high yield, high fidelity, and tailorable fabrication of bio-photonic devices are achievable by the combination of the presented techniques.

One of the important points in synthesis of nano-particles (NPs) is regulation of the size of particles. Use of a protein cavity as a grow field of NP is one candidate procedure to make the size uniform. Here fabrication of nanometric aluminium and indium particles using protein, ferritin, are described. Aluminium NPs were observed as nano-crystals however indium NPs were amorphous. The indium NPs thus formed have uniform spherical shape with diameter of 6.6 ± 0.5 nm, while aluminium NPs were somewhat irregular in shape with about 6 nm diameter. At some special condition, proteins are going to crystallize and that would provide regularly arranged sites for NPs. This means crystallization of proteins provides regular array of NPs. Regular two-dimensional (2D) arrays of indium nanoparticles are successfully produced by crystallising ferritin with indium NP (In-ferritin) on a solid surface using the denatured protein film method or direct spreading. The lattice constant of NP arrays obtained by the denatured protein film method is 13.3 nm with hexagonal packing, and arrays of more than 4 μm² in area can be obtained by transfer onto silicon wafer. Square lattice with spacing of 9.3 nm is also obtained by direct spreading of salt free In-ferritin on solid surface. The square lattice is expect to be bilayer because spacing of 9.3 nm cannot be performed by monolayer.

We report on a quantum dot (QD) structure grown on a 4'' GaAs substrate by metal organic vapor phase epitaxy (MOVPE), which consists of five stacked InAs/InGaAs/GaAs QD layers embedded in the center of a typical in-plane waveguide. The density of the QDs is about 2.5 x 10¹⁰ cm^-2 per QD layer. The photoluminescence (PL) peak wavelength at 1322 nm corresponding to the interband transition of the QD ground states was observed at room temperature with a full width at half-maximum of 49 meV. A good uniformity of the QD structure across the 4'' wafer was verified with a variation of the PL peak wavelength of 0.9 % from the wafer center to the edge. Top p-contacts and a bottom n-contact were processed on the QD structure, and electroluminescence (EL) spectra were measured at different temperatures. An EL peak corresponding to the QD ground states emission was obtained at 1325 nm at room temperature.

We present degenerate and nondegenerate two-photon absorption spectra in a series of CdSe and CdTe quantum dots. The measurements show that the two-photon absorption (2PA) spectrum is strongly dependent on the quantum dot size and that the 2PA coefficient decreases as the quantum dot size decreases, and it is larger for the frequency nondegenerate process. Previously we had shown a theoretical analysis of these results based on a simple model using the effective mass approximation. Although this model works well for larger quantum dots, it fails for the smaller ones. Here we use the more (formula available in manuscript) model for the band structure and consider the hole band mixing in quantum dots to describe our data. This theory better describes the spectral structures for smaller quantum dots and also predicts the decrease of the 2PA coefficient with the decrease of quantum dot size. This is due to the reduction of the number of possible transitions and the blue shift of the optical bandgap from quantum confinement. This theory predicts the reduction of the 2PA coefficient with size, although our experimental results show an even stronger reduction.

In this paper, we report the effort to prepare a stable and homogeneous heat transfer nanolubricant and nanogrease in the oils (e.g. DURASYN^(R) 166) with the motivation of enhancing its properties such as thermal conductivity and lubricity. The process of making these fluids involves the dispersion of carbon nanoparticles into the oil through intermittent sonication and the use of additives such as surfactants. The rheology data indicats that the nanolubricant and nanogrease are non Newtonian fluids although the base DURASYN^(R) 166 oil is Newtonian fluid. The good characteristic results of the carbon nanotube greases are also reported.

As device sizes continue to approach nanoscale dimensions, it is essential to develop methodologies that enable more accurate and reliable fabrication of sub-10nm linewidths for devices. In this paper, we present a strategy of combining low-temperature and ultrasonic processing to produce uniform sub-10nm metal lines using electron beam lithography. Specifically, a cold development process that increases both the initial and critical electron beam doses, and thus further improves the tunability, during ultrasonic development was employed. The use of ultrasonic development in combination with cold development caused a larger decrease in the critical dose than the decrease of the initial dose, which results in a resist contrast that is higher than when ultrasonic or cold development are used alone. The increase in the contrast helps to achieve finer line patterns. Additionally, the increase of contrast and critical dosage results in higher pattern uniformity and reproducibility. Using this strategy, metal lift-off patterns with an average linewidth of less than 10nm were achieved using a conventional beam voltage of 15kV, providing narrower average linewidths than are obtained without this strategy (typically 20-30 nm). Thus, this methodology provides a way to reliably fabricate sub- 10nm uniform patterns for the development of the next generation of nanoscale electronic devices, interconnects, and, ultimately, integrated circuits.

A comprehensive model for distributed Bragg Reflector (DBR) based on thin film optics is developed. Detailed refractive index calculations for GaN, AlN, AlGaN and InGaN are included in this model. Our model can predict DBR performances for index variations, layer thickness fluctuations, and different numbers of quarter-wave stack pairs in a DBR.

The use of fiber optics can greatly reduce device size while maintaining the sensitivity. Recently, nanostructures, especially metallic nanoparticles, have been incorporated into fiber optical sensors to obtain high sensitivity and specificity. Here, we propose a new way to integrate aligned nanorods onto optical fibers using a modified oblique angle deposition (OAD) technique. By rotating the optical fiber with a proper tilting angle, aligned nanorods from materials such as metals, semiconductors and metal oxides have been successfully deposited. With a slight modification, multilayer film/nanorod and nanorod/nanorod structures have also been demonstrated. This method has the advantage to coat aligned nanorods on optical fibers at low temperature, and is particularly promising for preparing nanostructured fiber optical probes for sensor applications. We also demonstrate that the optical fiber with its tip coated with Ag nanorod arrays can act as a Surface Enhance Raman Scattering (SERS) sensor.

Reflectance spectrum calculations of double- and triple-layer antireflection coatings based on porous silicon layer are performed using the optical matrix approach method. Obtained results are compared with the reflectance spectrum of the SiO₂/TiO₂ double-layer antireflection coating. A low reflectance value of both double- and triple-layer antireflection coatings made of porous silicon is observed in comparison to that SiO₂/TiO₂ antireflection coating. These results are of importance for solar cells application.

A DNA memory is a storage system utilizing inherent features of DNA, which is promising as a fundamental technology of nanoscale computing. Realizing a practical DNA memory requires establishment of a method for accessing to and controlling certain DNA strands among a lot of strands in a solution with high accuracy and selectivity. For addressing this issue, we have proposed a DNA memory using photonic techniques: the photonic DNA memory. Manipulation of information by using DNAs on a nanoscale and light on a microscale is effective in achieving a high capacity and flexible memory. This paper reports on experimental results of photonic translation of DNAs containing data between microscopic beads and a substrate. The technique is expected to be useful in writing, transferring, and reading necessary information in a photonic DNA memory effectively. In the experiments, we prepared a glass substrate coated with titanylphthalocyanine for light absorption and gold for DNA attachment. Data container DNA strands, which were labeled by fluorescence-dye for observation, were attached on the substrate by hybridization with their complementary strands immobilized on the substrate; then a solution containing 6-micrometer-diameter beads on which DNA strands including the complementary sequence of the data container DNA was placed on the substrate. After a bead was irradiated with a laser beam and translated on the substrate, the fluorescence intensity of the substrate decreased and that of the bead increased. The result indicates that the data container DNA was moved from the substrate to the bead owing to change of the temperature of the solution at the irradiated area.

Investigations of optical recording processes in amorphous chalcogenide layers were extended to the compositionally modulated amorphous nanomultilayers made of different pairs of chalcogenide glasses from As-S(Se) systems or pairs of chalcogenide glasses and metals, dielectrics. This type of recording is connected to the light-stimulated mass transport across the interfaces, possible phase transformations and correlated changes of optical parameters (absorption, refraction, reflection). The interconnections between the compositional modulation at nano-scale dimensions (~3-10 nm) and possible improvement of recording parameters (the rate and degree of optical bleaching, darkening, local changes of the thickness and of the refractive index, spatial resolution) were established.

Anti-reflection structure having sharpened corn shape is reproduced by nano casting method. Firstly, the master quartz structure is transferred to UV curable resin to fabricate the replicated mold of the master structure using nano casting method. Next, the anti-reflection structure is transferred to PMMA film using the replicated mold by the nano casting method. To avoid the defects at the mold releasing, thin sacrifice layer is coated on the replicated mold. Also, the molecular weight of the PMMA is optimized to improve the yield of the releasing process and transferred pattern shape. Fine anti-reflection structure is fabricated by the proposed process using the nano casting method without damages to the master structure.

The brilliant metallic blue in wings of Morpho butterflies has a mysterious feature. The blue luster is produced from the butterfly's scale, which does not contain a blue pigment at all. The origin of the coloration is then attributed to a microscopic structure that can also explain its high reflectivity. However, its optical characteristics on the scattered wavelength contradicts obviously the grating or multilayer, because it appears blue from wide angle. The mystery of the lack of multi-coloration has recently been explained using a model with a peculiar optical structure, and experimentally proven by fabricating the optical film by controlling the parameters in nanoscale. The reproduced Morpho-blue was found to be important from viewpoint of a wide variety of applications. However, the fabrication process of the nano- structure is too costly due to conventional lithography method. To solve the problem, nano-casting lithography (NCL) was newly applied using UV curable polymer to replicate the nanostructure and improve heat-resistance for the following process of deposition. After fabrication of the nano-patterned polymer structure by the NCL, TiO₂ and SiO₂ layers were deposited and the Morpho-blue structure was successfully replicated in low cost. The reflective characteristic of the replicated structure was found to reproduce the basic properties of the natural Morpho-blue, as well as the originally fabricated Morpho-blue.

We present techniques to generate multiple vortex with different topological charge by means of diffractive optical elements. Analytical formulae to describe the Fresnel and Fraunhofer diffraction of the Gaussian beam by a helical axicon (HA) are introduced. The relations are presented as a series of the hypergeometric functions. By setting the axicon parameter equal to zero, the solution for the HA changes to that for the spiral phase plate (SPP). The performance of the aforesaid optical elements is tested both through computer simulation and by experiments using a spatial light modulator, in view of optical miroparticle manipulation.

Investigations of interdiffusion effects in chalcogenide nanomultilayers were extended towards the Bi(Sb)/As₂S₃ structures. It was shown that the interdiffusion in these nanocomposites was mainly determined by thermal effects due to the direct heating or to the influence of the intensive laser beam unlike the chalcogenide-chalcogenide nanostructures, where the photo-induced effects may dominate. Solid-phase synthesis, efficient amplitude-phase modulated optical relief recording can be performed this way.

In this work, we report three-dimensional memory by recording optical bits with irradiation of near-infrared femtosecond laser pulses and by reading photoluminescence change in the blue due to permanent reduction of Eu³⁺ to Eu²⁺ in sodium borate glasses. We produced a multilayered micro-bit pattern which was read out by detecting the blue emission from the 405 nm excitation with a high S/N ratio. The readout was performed by using a scanning reflection-type confocal microscope.

We have developed a reliable process to fabricate high quality 2D air-hole and dielectric column InP photonic crystals with a high aspect ratio on a STS production tool using ICP N₂+Cl₂ plasma. The photonic crystals have a triangular lattice with lattice constant of 400 nm and air-hole and dielectric column radius of 120 nm. Large efforts have been devoted on developing a proper mask. We obtained a perfect, clean and vertical profiled SiN_X mask. The next main effort is InP pattern transfer in Cl₂+N₂ plasma. Etching selectivity, smooth sidewall and etch profile are directly related to plasma process condition, besides the quality of SiNX mask. We have optimized the N₂+Cl₂ plasma condition to obtain high aspect ratio, vertical profile and smooth sidewall InP structures. Cylindrical holes (2 micron depth) and rodlike pillars (2.4 micron height) are uniformly fabricated. An aspect ratio of 18 for 100nm trench lines has been obtained. AFM measurement evidences that etched surfaces are smooth. The root mean square roughness of pillar and hole is 0.7 nm and 0.8 nm, respectively. The optical transmission characterization of ridge waveguides has been carried out. Transmission spectrum of 1 micron wide waveguide has been obtained.

Nanocrystalline silicon layers ( 3-35nm ) have been formed upon single-crystal silicon substrates of very large area (100 cm²), multicrystalline silicon substrates and metallurgical silicon substrates by stain etching. We studied optical and structural properties of nanocrystalline silicon by photoluminescence, reflection, scanning tunnel microscopy, scanning electron microscopy, Auger electronic spectroscopy and SIMS methods. Researches of properties of nc-Si, received by a method of chemical processing, have confirmed an opportunity of creation of this multifunctional material with stable characteristics. The authors have observed the sensors systems with use of nanocrystalline silicon as a sensitive layer, which properties depend on thickness of a received layer and are controlled by parameters of technological process. On an example of the photoluminescent sensor with nc-Si layer it is shown, that such sensor can be successfully used for definition of small concentrations of toxins (pesticides phosalone 10^-8-10^-9 mol/l ), and also for specific biological pollutant, such as protein components, polysaccharides, cells used during biotechnological synthesis.

Highly transparent polycrystalline lanthanum-modified lead zirconate titanate (PLZT) thick films were prepared using aerosol deposition method (ADM) of calcined complex powders. Effects of incident angle of aerosol and particle size as well as annealing temperature on optical and electro-optic properties of films were investigated. The film with higher transparency was obtained with smaller particle, because the aggregation frequency of particles in aerosol decreased with reducing the particle size. The transparency of the films increased with decreasing the incident angle of aerosol. This is presumably due to the fact that the optimal incident angle of aerosol results in the reduction of impurity and pore, which makes the film to be denser micro-structurally. The XRD peaks of as-deposed films shifted to lower angle side, indicating that large compressive stress, which was generated by mechanical collision of particles, acted in the films. But the stress was eliminated through annealing process. The birefringence change in annealed film increased exponentially with an applied electrical field to reach 0.0036 at 100kV/cm. To make a multimode waveguide, the PLZT film with 22 μm thick was formed into a silicon groove, which was fabricated through anisotropic wet etching process. The far field profile of multimode optical wave transmitted through the fabricated PLZT waveguide was successfully observed and could be controlled with an applied electrical field.