This paper is a description of a verifiable work recipe, it is not an ab initio justification. The optical realm of waves straddles two superimposed media: one matter-free space, the other diffracting material media. Descriptions, initially restricted to isotropic media, soon accounted for anisotrophy and its ensuring birefringence. Subsequently, nonreciprocity, helicity and time reversal asymmetry manifested themselves in e.g., Fresnel-Fizeau- and Faraday effects, natural optical rotation, Sagnac effect (inertial reference sensor); all are to be included in a general description. The constitutive elements of six effects unite in a valency four tensor, leading to a universal wave equation, which retains validity for general coordinates. The use of holonomic references holds a key to such a description. Since the metric field emerges as a constitutive agent of vacuum, a metric-free rendition of the Maxwell equations is a sine qua non for separating field- and constitutive description. Submitted to this principle of constitutive separation, Schrodinger's equation interestingly reveals itself as describing ensembles of identical systems not single systems.

The magnetoelectric (ME) effects go back to the conjecture of Pierre Curie in 1894 that materials might exist that can be polarized electrically by means of a magnetic field and magnetized by means of an electric field. The different kinds of such ME effect known today can be classified on a thermodynamic and symmetry basis. This paper surveys the thermodynamically reversible Induced effects, i.e. the linear and bilinear ME effects, the piezomagnetoelectric and thermodynamically irreversible Spontaneous effects, i.e. electric field, magnetic field and stress induced switching or reorientation of domains with spontaneous polarization, spontaneous magnetization, spontaneous toroidal moment, spontaneous deformation. Examples of insulating materials displaying the different kinds of ME effect are discussed. Useful applications of ME effects are so far restricted to research: determination of magnetic symmetry, a powerful complementary tool to neuron diffraction, study of magnetic phase transitions, magnetic phase diagrams, toroidal moments, poling of antiferromagnetic domains, ME spin chirality control, linear magneto-optic effect, ME spectroscopy at optical frequencies.

Optical activity was found in 1811 by Arago. However, optical activity of solids is extremely small and overwhelmed by existing birefringence, so it could not be measured until the high accuracy universal polarimeter (HAUP) was developed by us in 1983. The HAUP method enables us to measure optical activity and birefringence of any solids even belonging to monoclinic and triclinic systems. The principles of the HAUP and the more generalized one are given. The applications of the HAUP method to various kinds of solids, i.e., the elucidation of the origin of the incommensurate state of ferroelectrics, optical activities or monoclinic crystals, huge optical activity of high polymer sheet, and the first measurement of a protein, lysozyme, crystal are described. These applications illustrate that axial tensorial consideration provides otherwise inaccessible insight of previously unsolved problems. Therefore we stress the necessity of developing a new research field defined as chiral physics, where axial tensors play essential roles.

A theoretical model of a quantum well layer is described for the purpose of analysing nonlinear optical interactions between an electromagnetic plane wave propagating normal to the plane of the quantum well in the ultrafast temporal regime. The model consists of the wave equation for the electromagnetic vector potential coupled to a finite-dimensional quantum system described by the Liouville equation for the density matrix. A 3-level example which represents vector interactions in an isotropic medium is shown to be completely integrable with roational symmetry.

We present summary of wave propagation and interaction in photoreflective polymers. Energy exchange between waves, and higher order generation are studied. Also, possibly applications such as edge enhancement and edge enhanced correlation are described.

Nonlinear magneto-optics and the propagation of light beams are introduced through the use of layered structures. Linear magnetoopotic layers are deployed with varying degrees of complexity in structures that have components that can become optically nonlinear. The properties of spatial solitons in the presence of interfaces are investigated and some new ideas using magnetooptic materials to control spatial solitons are introduced. Some comments on the range of modern magnetooptic materials are made, followed by a derivation of envelope equations for TM modes. The control of spatial solitons through the use of current- strip electrodes is simulated and an interesting split-field method of generating perturbative analytical results is presented. It is emphasized that these systems are very easy to create experimentally to any degree of sophistication. The approach, therefore, is very promising for future all-optical processing.

A full-wave integral equation Green's function code in the spectral domain has been implemented using the finite Fourier transform consistent with layered structures modelled in a cross-sectional region. The Green's function handles very complex materials, such as uniaxial and biaxial electric or magnetic crystals, rotated crystals, asymmetric off-diagonal element tensor electric or magnetic materials, non- hermitian tensors, simultaneous electric or magnetic behavior, and optical activity. The basis function due to intrinsic asymmetry caused by the material tensors. This asymmetric basis set may be reduced to a perfectly symmetric set in appropriate cases, if desired. Theoretical issues related to determining the permittivity or permeability tensors from the propagation constant, which may be obtained from a design specification or an experimental measurement, will be covered in mathematical generality for rotated systems or arbitrary bias field orientations. Specialization to principal axis crystallographic orientation or bias field direction with respect to the device coordinates will then be made, and subsequently examination of static electric field induced anisotropy in a ferroelectric loaded multi- layered microstrip structure will be treated in a multi-step computational process of de-embedding the permittivity tensor elements from the propagation constant values.

The main applications of inhomogeneous materials with a continuous spatial variation of the electromagnetic properties as substrates for radiation components in the microwave and millimeter wave ranges are presented in this contribution. Firstly, we describe the way to obtain this kind of materials in the considered frequency ranges; secondly, we present some applications of such materials as substrates for integrated planar antennas showing the improvements respect to homogeneous ones. Particularly, we can observe improvements both in the radiation and in the scattering characteristics of such antennas.

Numerical and experimental results on the scattering of an electromagnetic plane wave by an array of novel planar chiral particles are presented in this paper. The geometry of the particles are chosen in order to obtain a depolarization of the scattered wave on a broad frequency band. We also present results corresponding to arrays with the chiral particles connected to passive linear electronic loads. By varying the loads, we demonstrate, theoretically and experimentally, that the properties of depolarization can be electronically controlled. These results suggest a potential application of the studied samples in the design of agile polarization transformers.

The purpose of this paper is to report the experimental results on polyaniline-VO₂ composites in the 45MHz-18GHz frequencies range versus temperature and VO₂ mass concentration. The temperature dependence studied by classical heating and courant pulse and the percolation phenomena study have been carried out in both the semi- conductor state and metallic state. The VO₂ metallic oxide is remarkable through a reversible discontinuity of the electric conductivity which can reach five orders of magnitude at a transition temperature generally located at 68 degree(s)C. This transition is associated with the modification from crystal structure VO₂ which passes from a quadratic structure (metal state) to a monoclinic structure (semiconductor state) at the temperature T_t. The powder of VO₂ sintered in an induction oven. VO₂ was dispersed in a matrix of basic polyaniline, with mass rates of 10%, 30%, 50%, 70% and 90% of vanadium oxide. The strong dynamics of the composites beyond the threshold authorizes the use of a current to induce the temperature within the sample. The simulation of multi-layer of Jauman type, with commendable reflection and transmission in the frequencies range 8-12GHz will be shown.

An electromagnetic wave is transformed in a remarkable way by a transient magnetoplasma medium. The main effect of the temporal change in the parameters of the medium is the splitting of the source wave into new waves whose frequencies are different from the incident wave frequency. Several transient problems [1] involving slow or fast creation or slow or fast collapse of the plasma medium in the presence of a static magnetic field will be discussed. Approximate perturbation solution for the case of rapid temporal change of the plasma medium, based on time-domain Green's function, will be presented. WKP or Adiabatic analysis for the problem of slow temporal change of the plasma medium will also be presented. Finite Difference Time Domain (FDTD) method of numerical solution will be developed. Several interesting results obtained by the author by using the approximate solutions and verified by the FDTD method will be discussed. The more important results are: (1) frequency upshifting with power intensification of a whistler wave by a collapsing plasma medium, (2) conversion of a whistler wave into a controllable helical wiggler magnetic field, (3) mode coupling due to a magnetized plasma in a cavity, and (4) frequency down-shifting due to switched plasma layers in the presence of a background magnetic field. A switched magentoplasma can act like a frequency transformer. The source wave can be generated in an available frequency band and the switched plasma device converts the source wave into a new wave in a frequency band not easily obtainable by other methods. Frequency shifting mechanism can be applied for plasma cloaking of satellites and aircraft and for producing short-chirped-pulses as ultra wide band signals. Recent proof of the principle experiments confirmed many theoretical results. Many more experiments need to be done to study the scalability of the results. Fast Switching of magnetized plasma is a challenging experimental task.

Magnetoelastic thin film sensors can be considered the magnetic analog of surface acoustic wave sensors, with the characteristic resonant frequency of the magnetoeleastic sensor changing in response to different environmental parameters. We report on the application of the magnetoeleastic sensors for remote query measurement of pressure, temperature, liquid viscosity and, in combination with a glucose- responding mass-changing polymer, glucose concentrations. The advantage of using magnetoelastic sensors is that no physical connections, such as wires or cables are required to obtain sensor information allowing the sensor to be monitored from inside sealed containers. Furthermore since it is the frequency response of the sensor that is monitored, rather than the amplitude, the relative orientation of the sensor with respect to the query field is unimportant.

In this talk, which is tutorial in nature, I present a review of the phenomenon of magmetostriction in magnetic materials. Magnetostriction has its origin in the spin-orbit coupling of the electrons responsible for the magnetization. Terfenol-D (Dy_0.73Tb_0.27Fe_1.95) has such an enormous magnetostriction parameter that is has acquired smart material status. Suitably oriented crystals have strain changes of approximately equals 0.2% when the magnetization direction is rotated by 90 degree(s). Devices based on t his material include microphones, inch-worm motors, actuators, etc. On a fundamental level, magnetostriction provides an interation mechanism between photons and phonons. Calculations and experimental data for 17 GHz microwave reflection and transmission measurements are presented. Finally, possible experiments at optical frequencies are suggested.

The purpose of this paper is to highlight some recent developments in electromagnetic homogenization theory. The aim of any homogenization formalism is to derive or at least provide solid estimates for the constitutive parameters of a homogenized composite medium (HCM) based on a knowledge of the constitutive parameters and various geometrical/topological quantities pertaining to the constituent mediums. Best know among the various formalisms are those associated with the names of Maxwell Garnett and Bruggeman. Both linear and nonlinear homogenization problems shall be considered here.

We present and discuss the optical properties of thin film materials, which are inhomogeneous on the nanometer scale. Particular emphasis will be given to the specific optical behavior of the cluster matter. The cluster shape, cluster size, and the inter-cluster-distance control the latter. When the dielectric functions on the constituents are given, the influence of these spatial parameters on the optical properties may be understood in terms of the Generalized Mie Theorie (GMT), which provides a quantitative description to the optical behavior of such systems, no matter whether the cluster arrangement is preferable one-, two-, or three-dimensional. We will mainly focus on the case, when two-dimensional cluster aggregates are embedded into ultrathin solid films with a thickness of only a few nanometers. In this case, the film thickness appears as a third spatial parameters that is crucial for the optical behavior of the whole system. An appropriate choice of the material combination allows us to manipulate the optical film properties by even subnanometer changes of the mentioned spatial parameters. For instance, absorption line shifts for some hundred nanometers in wavelength may be achieved this way. As examples, amorphous hydrogenated carbon as well as metal island films in various environments will be discussed.

A theory of optical, infrared, and microwave response of metal- dielectric inhomogeneous films is developed. The generalized Ohm's law is formulated. In this approach electric and magnetic fields outside a film can be related to the currents inside the film. Our computer simulations, show that the local electric and magnetic fields experience giant spatial fluctuations. The fields are localized in small spatially separated peaks: electric and magnetic hot spots. In these hot spots the local fields (both electric and magnetic) exceed the applied field by several orders of magnitude. The high-order field moments that characterize the average enhancement of Raman scattering and nonlinear optical processes are very large and frequency independent in a wide spectral range.

The novel composite material based on middle density polyethylene on one hand and thermoplastic chalcogenide glass on other hand has been worked out. Both materials used in the research are highly transparent in the middle and far IR but refraction indexes of components differ dramatically. The basic materials, polymer and glass, have close viscosities at the temperature of polyethylene processing. This fact allowed use of the extrusion technique for homogenization purposes. We proved, that the controlled structure of a composite could be derived through the varying of technological parameters of the mixing process. Single- and twin screw extrusion processes obtained compositions, which contain up to 50% particles of chalcogenide glass, which were dispersed in the polymer matrix. The highly homogeneous compositions that contain perfect spherical glass particles of 1-2 micrometers in diameter dispersed into polymer matrix were obtained as well. Highly oriented structures involving chalcogenide glass fibers immersed in the polymer matrix were prepared under high stretch speeds as well. Such fiberlike structures exhibited pronounced polarization properties. We studied the optical properties of the composite and came to the conclusion that the controlled structure of the composite allows variation in its optical properties. It was established that it is possible to produce a composite that is opaque in the visible and near IR, and highly transparent in the 2-25-micrometers wave length band. Light scattering on oriented and disordered structures was studied by the IR spectro-goniometer. The novel composite which was developed by our group is intended for various IR-optics applications.

We analyze microstructure and optical properties of thin light-guiding nanocompositte planar structures produced by implantation of MeV Ag into LiNbO₃. The structures demonstrate such prominent features as change of color from yellow to pink accompanied by the appearance of light guiding after heat treatment of the implanted sample at 500 degree(s)C for one hour in open air. TEM analysis shows that before heat treatment the implanted region consists of amorphous and porous lithium niobate and nanoclusters of metallic silver localized near the edge of the nuclear stopping region. The surface plasmon resonance peak attributed to the nanoclusters is located near 430 nm giving yellow color to the sample. After heat treatment the implanted region re-crystallizes in the form of randomly oriented sub-micron grains of lithium niobate doped with enlarged and dispersed silver nanoclusters. Optical prism coupling analysis shows that the implanted region performs as a planar light guide with the refractive index apparently higher than the nuclear stopping region beneath it. In addition, the surface plasmon resonance peak of the nanoclusters moves to 550 nm giving pink color to the sample. Using computer simulations based on the Mie model, we explain such significant red frequency shift of the plasmon resonance by the increase of the effective refractive index of the host material after recrystallization and elimination of porosity caused by heat treatment. Theoretical data are in good agreement with experimental spectra of the optical extinction of the sample before and after heat treatment. This is also in agreement with the fact that the implanted planar structure becomes a light guide with substantially increased effective refractive index. Fabricated nanostructure can find application in ultra-fast photonic switches where light guiding is combined with the optical nonlinearity of the third order enhanced by the plasmon resonance.

In this paper we make an initial attempt at quantifying the potential of Thin Film Helocoidal Bianisotropic Mediums for optical filters that are also polarization sensitive. Using multiple twist discontinuities we are also able to demonstrate a novel multi-pass narrow-band polarization sensitive filter.

The spectral signatures of non-axially excited, absorbing TFHBM layers are determined. The dispersive properties of the medium are described using a single-resonance Lorentzian model. Special emphasis is placed on the effect of absorption in the Bragg wavelength-zones, wherein the circular Bragg phenomenon occurs. Optical phenomena such as the optical rotation, circular dichroism and ellipticity transformation absorbing TFHBM layers are investigated. The effect of absorption on the functionality of TFHBM-based devices, such as multi-notch filters, are noted.

We have developed novel techniques for the preparation of micropatterned structures from thin films prepared by the block copolymerization of monomers using UV free-radial polymerizations. The process involves polymerizing the first monomer layer in the presence of an iniferter (initator-transfer agent-terminator) with a dithiocarbamate group to make a photosensitive polymer. Upon application of the second monomer layer on the first polymer layer and irradiation, a copolymer is formed between the two layers. Patterns are created on the films by applying a mask and selectively irradiating the surface. We have successfully polymerized poy (ethylene glycol) (PEG) onto a highly crosslinked material of poly(ethylene glycol) dimethacrylate. Various patterns have been created to determine the precision that can be achieved with this method. Preliminary results show that the patterns in the second monomer layer can be from 5 micrometers to 100 micrometers thick, with feature size as small as 5 micrometers , allowing the use of this material to high aspect ratio structures for micro-fluidics. In addition, applications of this type of material are also in bioMEMS, biomaterials, and biosensors for the selective adhesion of cells and proteins.

The last few years have seen a growing interest in the analysis of heterogeneous materials. These investigations lead to many applications as for example the development of absorbing materials or frequency selective surfaces. To analyse these structures we developed a method based on the domain integral representation of the fields. In a way to minimize the domain of integration, we considered the case of stacked gratings embedded or not in a slab. Then by using the Floquet's theorem, the domain of integration is limited to the reference element of each grating. An interesting application of such gratings is photonic band-gap materials. Indeed, these structures present a high reflection coefficient over a broad frequency bandwidth. Various photonic band-gap materials have been realized with metallic and dielectric gratings. Bistatic free-space measurements, performed from a 4 Ghz to 18 Ghz are compared to the simulations. The results obtained show a good agreement between the reflected field obtained with the model and the measurements. Since the localization of the frequency bandwidth is well evaluated we can use this model to build reflectors to antennas for example. An other important application of such structures is absorbing materials. This aspect will be presented as well.

The model describes the reflection, refraction and absorption of light rays by a single cylindrical filament according to the classical laws of optics. The overall light transmittance and reflectance of a single filament are then assumed to apply to an entire layer of such filaments. The optical behavior of the entire filament assembly is derived by adding successive filament layers, with the same optical characteristics, to those already present. The model describes the effects of varying the relative refractive index of the filament material and the filament radius on the transmittance and reflectance of the filament matrix, and in individual filaments, influences the perceived color depth. The dye may be evenly distributed throughout each filament or located in a ring close to the filament periphery. The model also considers the case where filaments near the surface of the assembly are colored while those in the interior are not. The results are discussed in relation to practical coloration experience.

Dielectric versions of helicoidal bianisotropic mediums (HBMs) have been realized recently as chiral sculptured thin films (STFs). With a view to understanding their structure-response relationships, these STFs are modeled as periodically arranged stacks of dielectric ellipsoidal inclusions in air. The inclusions are assumed to be randomly dispersed and similarly oriented in each stack, and the Bruggeman formalism is adopted for local homogenization. The constitutive properties are examined as functions of inclusion shape, volume fraction, and orientation angles. Optical signatures of the modeled thin-film HBM (TFHBM) layers, assumed axially excited, are calculated after solving a boundary value problem. Several conclusions drawn from the calculated spectrums of co- and cross-polarized reflectances and transmittances, true and apparent circular dichroisms, true and apparent linear dichroisms, ellipticity transformation, and optical rotation are presented.

The serial bideposition (SBD) technique is used to produce biaxial thin films with large linear birefringence and chiral (handed) media with large circular birefringence. Thin film wave plates and chiral reflectors of SBD silicon that have been fabricated show promise for applications in the wavelength range 800-2200nm. In particular we have deposited quarter-wave plates of metric thickness less than 1micrometers for the 800nm wavelength used in CD players, and half-wave plates of metric thickness about 3micrometers for the 1550nm optical communications wavelength. An observation of the Bragg resonance in a silicon chiral film in the 600-800nm wavelength range where the absorption is high but the linear birefringence is approximately equals 0.35, suggests possible applications even at the 633 HeNe wavelength. Polarizing elements that we have designed and fabricated for use with circularly polarized light in the visible and near infrared spectral regions are described. These include a two-layer Fabry-Perot filter that uses a structural phase discontinuity instead of a physical spacer layer to define the wavelength of a narrow spectral hole at the center of the Bragg dip. Further strategies, also based on phase discontinuities, are explored for adapting other filter designs from isotropic thin film filter theory to the circular case.

An approach is presented for the determination of the residual stresses and elastic moduli of particle systems resulting from computer simulations of particle or atomic deposition. The proposed technique is based on fundamental concepts of elasticity and is capable of capturing the variation of stresses and moduli as functions of position within the system. Application to a perfect FCC crystal and a simple particle system is demonstrated.

The anisotrophy of the morphology in oblique incidence, evaporated, columnar films has been studied previously only qualitatively, primarily by scanning electron microscopy. However, using atomic force microscopy and power spectral density analysis, new approaches are developed to quantify these anisotrophies in morphology in terms of their distribution functions of size, shape, spacing, and height. In addition, the biaxial stress of oblique angle columnar thin films prepared with varying angle of vapor incidence was measured by using a laser scanning method to determine changes in curvature. From this data, approaches to a quantitative model are proposed to describe the changes in morphology with varying angles of vapor incidence as related to ballistic aggregation and self-shadowing processes.

A novel new type of superlattice (SL) structure which consists of strongly coupled asymmetric double-well (ADW) in one period have been investigated to introduce a new degree of freedom for the device funtionality. The GaAs/A1As ADS-SL contained in a p-i-n diode structure was grown by molecular beam epitaxy, and the electroabsorption properties were measured by low temperature photocurrent spectroscopy. It is found that the introduction of the confinement potential asymmetry with respect to electric field will lead to the selectivity of spatially indirect Stark-ladder transitions associated with two different types of the localized hole states, thus providing a new way of modulating the oscillator strengths. Assignment of the possible optical transitions from the miniband to the Stark-ladder regimes as a function of field strength is elucidated in detail by transfer matrix calculations.

The phenomena for which the laws of geometrical optics are invalid in the case of beams are already very well-known. Such effects are known as non-speculars and many works about them already exist in the literature. Classically, the angular and longitudinal displacements are considered the basic non-specular effects, but there are the focal and width changes that, in any sense, are related with the previous ones. The foundation of these non-specular effects are related with the energetic interchanges that take place at the inrerface between two media, and an entropic foundation has been developed recently. From the optical point of view, the non-specular effects have been studied because they are important for guided waves and integrated optics. An experimental verification is more simple in the microwaves region because the range in angular change has a small value (the order of magnitude is 10^-3 radians), and the lateral displacement is comparable with the wavelength of the incident radiation. In this work, an impedance method (through the input impedance of the interface) is used to characterize different non-conventional structures: film on a medium with complex refraction index or multilayers with fractal distribution. The characterization of the reflection and transmission from the equivalent interface can be studied; also, very important is the relation between the angular and longitudinal changes with the entropy function for these cases.

Change the reduction temperature from 293 to 873 K permitted to prepare Ag-(natural clinoptilolite) samples with varying contribution of the different states of silver. At temperatures <EQ 473 K small Ag_n^m+ clusters (n < 10) and Ag_n subcolloidal particles (n approximately equals 10) are formed. Reduction at temperatures >= 573 K leads to disappearance of silver clusters and subcolloidal particles and formation of large silver particles on external zeolite surface. Prepared samples are stable in air.

We consider anisotropic stress in substrates coated with vacuum- deposited optically-anisotrpic thin films. Birefringent films with tilted-columnar and normal-columnar nanostructures and thin film helocoidal bianisotropic mediums are considered. In the case of tilted- columnar nanostructures, the sign and relative magnitude of the stresses parallel to the deposition plane and perpendicular to the deposition plane depend on deposition angle. We show that an ion-assisted overcoat, applied with the primary purpose of protecting optical properties, can be designed to provide effective compensation of stress.

In the work the range of deposition temperatures for the Ag-Cu systems, in which the oriented phase layering takes place, has been experimentally determined. The mechanism of this process has been analyzed. During the simultaneous deposition the well-oriented film structures with practically parallel mutual orientation of crystal lattices of Cu and Ag phases of high dispersity, alternating across the film thickness, have been received. At room temperature the two-phase nanocrystal heterosystem with lateral grain size of 10-20 nm has been formed. The closeness in the parameters of crystal lattices is, mainly, caused by the decrease of a_Ag to the values of 0.402-0.405nm in the substrate temperature range up to 570 K, which corresponds to solubility of Cu in Ag nanocrystals as much as 17%. When the substrate temperature increase in relatively narrow temperature range near 520 K, the oriented crystallization with parallel conjugation of the substrate and the lattices of Ag and Cu takes place with the grain structure dispersity preserved. The well defined double diffraction on the grains of both nanocrystal phases and the homogeneous concentration of components for the whole film thickness support the relative position of the phases as the alternating lamellae. Thus, during the film growth the direction leads to the formation of irregular layered compositions, consisting of very fine mutually oriented lamellae of both phases as large as several nanometers in diameter. The numerical values are in agreement with the experimental results.

In this work, using an electronic computer, the initial stages of condensation of two-component films have been investigated. The process of cluster formation from several atoms is described by a system of differential rate equations. It has been shown that the ratio of the number of clusters from the atoms of one or the other kind is dependent on the activation energy values for the surface diffusion of adsorbed atoms. The calculations of clusters density and sizes allow to make conclusions about the substructure of two-component films.

We report numerical time-domain simulations that reveal the continued reflection of an axially propagating optical pulse as it travels through a dielectric thin-film helicoidal bianisotropic medium (TFHBM) half- space, when the handedness of the pulse is the same as that of the medium. This phenomenon is dubbed pulse bleeding, and is a central feature of the spatio-temporal anatomy of the circular Bragg phenomenon.

ZnS:Mn has been in-filled in photonic crystals of submicron polymer spheres. The effect of the photonic bandgap on the photoluminescence (PL) properties of ZnS:Mn has been investigated. Because of the overlap of the transmission dip of the photonic crystal and photoluminescence band of ZnS:Mn, both supression and enhancement in the PL of the phosphor have been observed. A strong dependence of the fluorescence lifetime on the emission wavelength in the range of the stop band has been found. This strong dependence is believe to arise from the very low photon DOS (density of state) within the stop band of the ZnS:Mn in- filled photonic crystal as result of a high dielectric contrast between ZnS:Mn and the polystyrene spheres.

It is demonstrated that threshold reduction of two-photon polymerization is achievable by means traditionally employed for sensitivity enhancement for single photon photoinitiation, such as heavy atom enhancement or intersystem crossing, electron donor agent, concentration increase of initiator. It is shown that measured threshold is in reverse proportion to square root of initiator concentration, whereas observed length of induction period exhibits reverse proportionality to the square of light intensity. Overall, experimentally observed threshold values of two-photon induced photopolymerization are effected by all intermediate stages of energy transformation in the photochemical sequences leading to photoinitiation, in particular inter-system crossing of excited initiating molecules as well as by monomer reactivity.