This PDF file contains the front matter associated with SPIE Proceedings Volume 8464, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Commercial white solid state lighting consists of a blue light emitting diodes (LEDs) that excites a yellow-emitting phosphor powder, which is encapsulated with epoxy on top of the LED die. In this paper, we present the results of replacing the epoxy, with a promising new material, a deoxyribonucleic acid (DNA)-based biopolymer. Using this DNA-biopolymer as the host, has shown the potential for improving both the brightness and color of the light output.

This paper describes preparations of nano-scale patterned electric circuit based on high purity DNA molecules which are obtained from Salmon roe. The patterning on silicon substrate was carried out by an ink-jet method of aqueous solution of DNA. However, the Salmon-based DNA has a so huge molecular weight of over billions that even only 1wt% aqueous solution of DNA becomes gel without any fluidity. So, it is necessary to reduce molecular weights of DNA to increase fluidity of the aqueous solution of DNA, keeping the characteristic feature of double helical structures of DNA molecules to form metal-chlating complexes with various metal cations such as silver or copper cations. Several methods to reduce the molecular weight of DNA, including hydrolytic , enzymatic degradations and ultra-sonification. It was found that the best method to reduce the molecular weights (MW) of DNA was an enzymatic degradation of DNA to increase fluidity, thus being able to apply an ink-jet method for nano-scale patterning on a silicon wafer to form DNA circuit, followed by ion-crosslinking of DNA by dipping the patterned DNA circuit into aqueous solution of copper chloride. The DNA-CuCl₂ patterned circuit was reduced to copper nano-lines for electric circuit, by using hydrazine as a reducing agent. Thus, all DNA devices can be prepared by the combination of DNA transistor and circuit.

The semi-intercalation hypothesis^1–5 which states that an azo-dye Disperse Red 1 (DR1) molecule intercalates in a specific way into a biopolymeric material made of DNA complexed with the cationic surfactant CTMA, has successfully explained the main experimental results⁶ of laser dynamic inscription of diffraction gratings: short response time, low diffraction efficiency, single-exponential kinetics and flat wavelength dependence.⁴ Recent experiments indicate that the inscription of the grating displays some features of non-exponential behavior. To understand this complex dynamics we characterize local environment of polymeric chains in Monte Carlo modelling by analyzing some features of local free-volume (void) distribution.

The bio-organic thin film transistor (BiOTFT) with the DNA and DNA-surfactant complex as a dielectric layer shows memory function. In order to investigate the effect of surfactant structure on the OTFT memory device performance, different kinds of surfactant were introduced. Cetyltrimethylammonium chloride (CTMA), Lauroylcholine chloride (Lau) or Octadecyltrimethylammonium chloride (OTMA) as the cationic surfactant was mixed with DNA to prepare the DNA complex through the electrostatic interaction. In addition, the different molecular weight DNA also has been studied to analyze the effect of DNA chain length on the performance of the physical property. Many kinds of methods including UV-vis, Circular dichiroism (CD), I-V characteristic and atomic force microscope (AFM) have been applied to analyze the property of DNA complex. In conclusion, all of DNA complex with CTMA, OTMA and Lau were revealed to work as the bio-organic thin film transistor memory, and the device fabricated by Lau has the highest ON current and showed better device performance.

In this study, highly stable aqueous solutions of blends containing Deoxyribonucleic acid (DNA) and high k ceramics (BaTiO₃ or TiO₂) nanoparticles were processed. Dielectric and electrical properties of the as-prepared nanocomposites thin films were investigated. Dielectric Constant k values of 14 and capacitance density of 2.5 nF/cm² were achieved for a 40 wt.% BaTiO₃ loading at 1 KHz. The current-voltage (IV) measurements revealed electrical resistivity in the order of 10¹⁴ Ohm-cm with leakage current densities of the order of 10^-9 A/cm² for electric field biases up to 50V/μm.

Pure deoxyribonucleic acid (DNA) is known to be soluble in water only and exhibits poor temperature stability. In contrary, it is well known that the complex of DNA – with cetyltrimethyl ammonium (CTMA) is soluble in alcohols and can be processed into very good optical quality thin films by solution casting and spin deposition. Despite the success of DNA-CTMA, there is still need for new cationic surfactants which would extend the range of available solvents for DNA complex. We test and present experimental results of influence of new surfactants based on benzalkonium chloride (BA), and didecyldimethylammonium chloride (DDCA) for applications in all optical switching.

Biopolymers such as DNA can be used as a host material for nonlinear optical dyes for photonic applications. In previous work by Heckman et al. (Proc. SPIE 6401, 640108-2), the chromophore Disperse Red 1 (DR1) was combined with CTMA-DNA (a water-insoluble DNA/surfactant complex) to produce an electro-optic waveguide modulator. However, DR1 does not bind strongly to DNA and has a low first hyperpolarizability (β). We have used theory-aided design to develop and synthesize a novel chromophore with strong affinity for DNA and higher β than DR1. We have also developed a surfactant containing a photocrosslinkable moiety that can be used to harden thin films of the DNA/surfactant/dye composite under ultraviolet light. The optical and thermal properties of these materials and outlook for device applications will be discussed.

We succeeded to observe fluorescence enhancement and tunable laser emission from spin coated films of DNAcetyltrimetylammonium (CTMA) complex doped with weakly fluorescent cyanine dyes, DiQC₂(1) and DiQC₂(3) which were optically excited by interfering two beams forming a induced dynamic grating. Wavelength tuning of the laser emission was achieved by varying the angle between the pumping beams determining the grating period on the film. Degradation processes of the dye-doped films of DNA complex and PMMA were investigated and compared by monitoring absorption spectra after continuous excitation with a pulsed laser. Roles of DNA for fluorescence enhancement and improved durability were confirmed for these cyanine dyes.

Aside from salmon DNA, other DNA sources were explored namely, herring and onion, to prepare DNAsurfactant complex, which will be used as a template for dyes undergoing Forster Resonance Energy Transfer (FRET). Also, salmon DNA of low and high molecular weight were compared. This study aims to assess the effect of using different DNA sources and molecular weight on the efficiency of energy transfer between the dyes, coumarin 480 (Cm 480) and 4-[4-(dimethylamino)styryl]-1-docosyl-pyridinium bromide (Hemi 22 and to understand the fundamental properties of DNA-CTMA as a supporting matrix for optoelectronics applications.

In this Keynote presentation, we will review the use of selected biosystems in relevant optical applications: Complementary DNA strands can be used to put chromophore couples, e.g. for energy transfer between donor and acceptor, at a desired distance. By using the appropriate oligonucleotide length, we have spaced donor and acceptor at the Förster distance to show the influence of a carefully designed photonic bandgap on the Förster resonant energy transfer (FRET) efficiency. Amylose can be used to optimize the conformation of extended chromophores. Long conjugated systems show enhanced optical properties, but only in the all-trans conformation. This unlikely situation has been enforced by including the elongated molecule as a guest in the amylose host. The theoretically predicted enhancement in nonlinear optical polarizability, linear with conjugation length, has been demonstrated, but only when the chromophore was in the amylose. Fluorescent proteins can be used in cellular imaging. We will focus on the recent development (by genetic engineering) and characterization (by hyper-Rayleigh scattering) of fluorescent proteins for combined multiphoton fluorescence and second harmonic imaging. A small rainbow of fluorescent proteins has been characterized for their nonlinear optical properties.

The combined association of magnetic and luminescent properties into a unique object (especially nanoparticle) has recently driven considerable interest since it offers non-invasive dual imaging and permits contactless addressing and vectorization. We report on the use of organic materials, known to emit in the solid state and form size-controlled nanoparticles upon precipitation. They generate cohesive magnetofluorescent hybrid nanospheres without requiring prior coating of the inorganic entities. Their internalization in living cells is successfully proved by two-photon laser scanning fluorescence microscopy and TEM imaging. Deeper photophysical analyses reveal two kinds of structure depending on the solvent and concentration conditions.

Organic nanocrystals (ONCs) similarly to inorganic ones show interesting size effects. It has been already observed that their luminescence properties can be changed in terms of enhanced luminescence and spectral shift of fluorescence bands as compared to bulk materials. Usually these effects are observed for much larger size of nanoparticles from 50 nm up to 1000 nm. Noncentrosymmetric and fluorescent organic crystals are rare but particularly interesting as they exhibit both nonlinear optical properties like Second Harmonic Generation (SHG) and fluorescence. Such ONC's could serve as fluorescent and SHG probes for bio-imaging purposes simultaneously. This could be beneficial for situation in which the dynamics of ordering of biological systems has to be studied. Here, we report on 3-(1,1-dicyanoethenyl)-1-phenyl-4,5- dihydro-1H-pyrazole (DCNP) compound which forms nanocrystals, exhibits large shifts of fluorescence maximum with size and strong SHG signals. When embedded in polymeric or biopolymeric matrix DNA-CTMA shows efficient amplified spontaneous emission. The unique properties of this compound in its various forms from molecules, ONC's to macroscopic single crystals are studied and discussed.

In this paper we present our current research in exploring a DNA biopolymer for photonics applications. A new processing technique has been adopted that employs a modified soxhlet-dialysis (SD) rinsing technique to completely remove excess ionic contaminants from the DNA biopolymer, resulting in a material with greater mechanical stability and enhanced performance reproducibility. This newly processed material has been shown to be an excellent material for cladding layers in poled polymer electro-optic (EO) waveguide modulator applications. Thin film poling results are reported for materials using the DNA biopolymer as a cladding layer, as are results for beam steering devices also using the DNA biopolymer. Finally, progress on fabrication of a Mach Zehnder EO modulator with DNA biopolymer claddings using nanoimprint lithography techniques is reported.

DNA-based bio-dielectrics incorporating sol-gel have been investigated for energy storage applications. Salmon DNA hybrid films blending sol-gel-ceramics with DNA-CTMA have potential for increased dielectric constants and higher environmental stability compared to DNA only films. Thin film capacitor devices were fabricated and characterized, showing stability in dielectric properties and reliability in voltage breakdown measurements, attaining values consistently at 300 V/um. Temperature-dependent dielectric properties as well as dielectric stability as a function of thermal cycling of these hybrid films are also discussed.

Monodispersed semiconductor nanocrystals or quantum dots (QDs) specifically immobilized on the surface of purple membranes (PMs) containing bacteriorhodopsin (bR) can harvest light in the UV to blue region, which cannot be absorbed efficiently by the PMs alone, and transfer the harvested energy to the retinal chromophores of bR via highly efficient Förster resonance energy transfer (FRET). CdTe or CdSe/ZnS QDs with a quantum yield as high as 70% have been used to estimate different parameters characterizing the improvement of the bR biological function caused by nanocrystals. AFM examination has shown that the most FRET-efficient QD–PM hybrid structures are characterized by the highest level of QD ordering; hence, AFM imaging of bR–PM hybrid materials provides the basis for optimization of the assembly design in order to engineer bio-hybrid structures with advanced optical and photovoltaic properties. Oriented bR-containing proteoliposomes tagged with QDs at a QD-to-bR molar ratio of up to 1:5 have been engineered and used to analyze the photoresponse, with the bR proton pumping considerably increased. Finally, the kinetics of the potential/current generation in films of oriented bR containing or not containing QDs have been analyzed. Incorporation of QDs resulted in an increase in the potential/current generation rate and in an almost fourfold increase in the rate of Mform formation. Thus, the improvement of the bR native function by QDs may be caused by two reasons: an extension of the range of utilized light and an increase in the rate of the bR photocycle.

Supercontinuum laser sources provide a very useful tool to characterize materials and scattering media such as nanomaterials in suspensions, aerosols or paint coatings. Onera, The French Aerospace Lab, has developed a fast, in-line and comprehensive optical characterization method. The hyperspectral polarized angular light measurements by tumor cells exhibit a unique signature. We propose an original way to probe tumor cells in in-vitro samples. First experimental results are presented with potential applications. This is the first time in our knowledge that hyperspectral, polarimetric and angular signature of MCTS is reported.

The nano crystalline biphasic calcium phosphates of hydroxyapatite (HAp)/β-tricalcium phosphate (β-TCp) in the ratio 80:20 and 72:28 with interconnected porosity have successfully been prepared by co-precipitation method using mixed catanionic surfactants as template. The sample was calcinated at various temperatures for 8 h. The samples were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, Field emission scanning electron microscopy (FESEM) and thermal analyser. The samples calcinated at 750°C and 850°C show 75% and 89% of crystallinity respectively. Usually to obtain the biphasic calcium phosphates, either the medium will be set as acidic by altering the pH or the Ca/P ratio can be set below the value of 1.5. However this experiment was neither conducted with low Ca/P ratio (≤1.5) nor at low pH (≤7) to obtain the mixed phase. The combination of surfactants and calcination temperature controls the HAp/β-TCp ratio.