Fine-pitch ferroelectric domain gratings are extensively used for generation of light in the visible and near-infrared spectral regions through quasi-phase matched (QPM) frequency conversion. Sub-μm QPM devices enables demonstration of nonlinear optics with counterpropagating waves, a field of nonlinear optics which remains sparsely explored due to the difficulty of fabricatinghigh quality gratings. In recent years, bulk Rb-doped KTiOPO4 (RKTP) has emerged as a highly promising nonlinear materials for fabrication of fine-pitch QPM devices through periodic electric-field poling. RKTP possesses large optical nonlinearity and high resistance to optical damage, while demonstrating improved material homogeneity and lower ionic conductivity than its isomorphs, which are important features for poling. Although fine-pitch QPM gratings, as well as large aperture QPM devices, have been demonstrated, fabrication of sub-μm high quality QPM devices remains a challenge. The primary aim of this research was to develop a reliable method to fabricate high-quality sub-μm periodically poled RKTP crystals (PPRKTP) and exploit them in novel optical applications. For this purpose, a novel poling method was developed. It was based on periodic modulation of the coercive field through ion exchange, where K+ ions are exchanged with Rb+ in the crystal, to modulate the coercive field and the ionic conductivity. This enables periodic poling of higher quality and with shorter period than ever before. High quality PPRKTP with a period of 755 nm were fabricated and used to demonstrate the first cascaded mirrorless optical parametric oscillator (MOPO), as well as the first MOPO pumped by a Q-switched laser. PPRKTP samples for blue light generation were fabricated, and second harmonic generation (SHG) was investigated with a high power 946 nm fiber laser. Up to 2 W of blue power was demonstrated for bulk samples, where the output power was limited by absorption of the SHG, leading to thermal dephasing of the devices. Laser-written waveguides were fabricated in PPRKTP for the first time, and a record high SHG power of 76 mW was obtained. Finally, the high-temperature stability of ferroelectric domain gratings was investigated. This is of utmost importance when a PPRKTP crystal is used as a seed for crystal growth. It was found that for charged domains walls, the domain-wall motion was highly anisotropic with rapid movement in y-direction while only small movements were observed in the x-direction of the crystal. / Ickelinjära ferroelektriska kristaller med artificiella domängitter med perioder av några mikrometer används idag för generering av ljus i de synliga och nära-infraröda våglängdsområdena, genom kvasifasmatchad (QPM) frekvenskonvertering. Med sub-μm QPM domängitter kan man åstadkomma ickelinjära optiska effekter med motpropagerande parametriska ljusvågor. Detta är ett område av den ickelinjära optiken som fortfarande är tämligen outforskat på grund av svårigheten med att tillverka högkvalitativa domängitter.  Under de senaste åren har Rb-dopat KTiOPO4 (RKTP) blivit ett mycket lovande ickelinjärt material för tillverkning av QPM-gitter med mycket korta perioder genom periodisk elektrisk fält polning. RKTP kristallen har en hög optisk ickelinejäritet och den tål höga optiska intensiteter, samtidigt som materialet har bättre materialhomogenitet och lägre jonledningsförmåga än vad dess isomorfa kristaller har. De två senare egenskaperna har visat sig viktiga för att få en lyckad polning. Fastän QPM-gitter med kort periodicitet, liksom QPM-gitter med stor apertur, har demonstrerats, är tillverkningen av högkvalitativa QPM-kristaller med sub-µm perioder fortfarande en utmaning. Det primära syftet med denna avhandling var att utveckla en pålitlig metod för att tillverka högkvalitativa sub-μm periodiskt polade RKTP kristaller (PPRKTP) och utnyttja dem i nya optiska tillämpningar. I detta syfte utvecklades en ny polningsmetod. Den baseras på periodiskt jonutbyte, där K+ joner byts mot Rb+ i kristallen, vilket resulterar i en samtidig modulation av materialets koerciva fält och jonledningsförmåga. Detta möjliggör i sin tur periodisk polning av högre kvalitet och med kortare perioder än någonsin tidigare har uppnåtts. Högkvalitativa PPRKTP kristaller med en period på 755 nm tillverkades och användes för att demonstrera den första kaskaderade spegelfria optiska parametriska oscillatorn (MOPO), liksom den första MOPO processen pumpad av en Q-switchad laser. Vidare utvecklades PPRKTP-kristaller för generering av blått ljus via frekvensdubbling. Dessa utvärderades med hjälp av en högeffekts-fiberlaser vid 946 nm. Upp till 2 W av blått ljus erhölls för bulkkristallerna. Uteffekten begränsades av absorption av det blåa frekvensdubblade ljuset, vilket ledde till urfasning i QPM-gittret p.g.a. termiska effekter. Laserskrivna vågledare tillverkades sedan i PPRKTP för första gången, och en rekordhög effekt på 76 mW erhölls via frekvensdubbling. Slutligen undersöktes stabiliteten hos de periodiskt polade domängitterna vid höga temperaturer. Det är viktigt att domängittrena är stabila när PPRKTP kristallerna används som ympämne för kristalltillväxt. Det visade sig att instabila domänväggar flyttade sig mycket anisotropt, med en snabb rörelse i kristallens y-riktning och en långsam rörelse i kristallens x-riktning. / <p>QC 20170519</p>

This thesis presents experimental studies of three different chemical reaction steps relevant for heterogeneous catalysis: dissociation, desorption, and oxidation. CO on single-crystal metal surfaces was chosen as the model systems. X-ray absorption spectroscopy (XAS) and x-ray emission spectroscopy (XES) provide information about the electronic structure, and were performed on CO/Fe to measure both a non-dissociative, and a pre-dissociative state. The measurement on the pre-dissociative state showed a π →  π* excitation, which implies a partly broken internal π bond in the molecule. Ultrafast laser-induced reactions were used to examine the dynamic properties of desorption and oxidation. Here CO/Ru and CO/O/Ru were used as model systems. Desorption of CO from a Ru surface involve both hot electrons and phonons. In the case of CO oxidation from CO/O/Ru a pronounced wavelength dependence of the branching ratio between desorption and oxidation was observed. Excitation with 400 nm showed a factor of 3-4 higher selectivity towards oxidation than 800 nm. This was attributed to coupling to transiently excited, non-thermalized electrons. Finally, by performing optical pump/x-ray probe XAS and XES changes in the electronic structure during the reaction could be followed, both for desorption and oxidation. In the CO/Ru experiment, two different transient excitation paths were observed, one leading to a precursor state, and one where CO moves into a more highly coordinated site. Using selective excitation in XES, these were shown to coexist on the surface. In the oxidation experiment, probing the reacting species located near the transition state region in an associative catalytic surface reaction was demonstrated for the very first time.

At the MAX-IV lab in Lund, there is a current goal to build a new soft X-Ray laser. The beam will be generated from a free-electron laser (FEL), which is an instrument consisting of high-speed electrons. The electrons move through alternating magnetic fields, causing the beam to become monochromatic. After the FEL, the Xrays will enter a beamline consisting of different optical components, such as mirrors, gratings and slits. This project investigated the necessary parameter values of the components, in order for the new X-Ray laser to focus the beam enough. The project consisted of a theoretical part and a simulation part. The use of so-called Kirkpatrick-Baez mirrors enables the beam to be very focused. The best focus achieved was 7.23um*10.87um for ''Pink beamline'' and the intensity at the end was 71.5%, which meant that only 30% of the rays were lost. For the monochromatic beamline, a loss of intensity is inevitable. With a pair of KBmirrors, this beam was focused to be 6.95um*9.80um. The energy spread is ranging from 6.198 eV to 0.3442 eV. The analytical calculations for the spot size matched well with the simulations. The pink beamline which was built in Ray satisfied the criterias of a spot size and intensity loss. The monochromatic beamline did fullfil the criterias of spot size and narrowing the energy spread. A loss of intensity will for this beamline be inevitable. Studying the misalignment effect showed that the components were most sensitive for vertical misalignment. The most sensitive parameters were the curvature of the mirrors.

Direct volume rendering techniques for scalar fields make use of transfer functions to map optical properties to the field; the field can subsequently be visualized through the drawing of isosurfaces in the volume spanned by the field. The utility of this approach is limited in the case of nested or clustered structures with the same isovalue and further does not easily allow for quantitative measurements of the visualized data. This report explores the use of topological structures (contour trees and Morse-Smale complexes) as an augmentation of traditional direct volume rendering and describes a fully functional implementation in the visualization software Inviwo. The implementation is evaluated through analysis of valency charge density fields in cubic MgO2 and FeO2. It is demonstrated that both contour trees and Morse-Smale complexes provide information and segmentation of initial volume data that allows for selective transfer function application (based on the segmentation), on-demand information on critical points and an overview of the scalar field through a topological representation embedded in the visualized volume. Analysis of the provided charge density fields show that contour trees generate physically irrelevant artefacts and thus are ill-suited for analysing highly symmetric data. On the other hand, the Morse-Smale complex approach is used to extract information of the bond strength of O-O contacts in MgO2 and FeO2 consistent with previous findings, as well as information on electronic charge configuration consistent with previous findings on MgO2. In the case of FeO2, the electronic configuration results are not consistent. This is speculated to be due to a combination of factors, most notably the lack of periodic boundary conditions in the implementation and the more complicated structure of FeO2.   In light of the partially accurate data analysis, as well as the added functionality and utility provided to visualization software, this approach to topology-guided visualization is considered promising and worthy of further study and/or development.

Kärnkraftsolyckan i Tjernobyl ledde till en spridning av radioaktiva ämnen över Europa och Sverige. År 2018 är det 32 år sedan kärnkraftsolyckan ägde rum och den enda radioaktiva isotopen som finns kvar i det svenska ekosystemet som följd av olyckan i en betydande mängd är Cs-137, på grund av dess 30-åriga halveringstid. Genom att bestämma aktiviteten hos svamp kan halten Cs-137 i mark uppskattas. Hösten 2018 kommer det tvärvetenskapliga massexperimentet Strålande jord att utföras i syfte att kartlägga denna halt i hela Sverige. Syftet med detta examensarbete var att nå resultat som är användbara vid aktivitetsbestämning av svamp. Ett numeriskt verktyg för analys av data ifrån gammaspektroskopi har konstruerats. Två metoder för att beräkna händelser (counts) i energitoppar i gammaemissionsspektra har formulerats och varit byggstenar för det vidare arbetet. Under arbetets gång har följande bestämts: effektiviteten hos en high purity germanium (HPGe) detektor, aktiviteten hos två svampprover, attenueringskoeffcienten av 662 keV-gamma för samma svampprover samt för vatten. För att kunna approximera en burk med svamp som en isotropt strålande punktkälla och få goda resultat behöver aktivitetsmätningarna göras med ett långt avstånd mellan provet och detektorn. Att mätningar måste göras på ett långt avstånd gör att approximationen bara är lämplig för ett svampprov med hög aktivitet, vilket blev tydligt i detta examensarbete då aktiviteten hos ett lågaktivt svampprov inte kunde bestämmas med god statistik trots att enskilda mätningar gjordes under närmare en veckas tid. Systematiska fel har inte tagits hänsyn till i detta arbete, utan enbart statistisk osäkerhet. / The nuclear disaster in Chernobyl brought radioactive substances over Europe and Sweden. In 2018 it has passed 32 years since the disaster and the only radioactive isotope that reamins in the swedish ecosystem at a signicant level is Cs-137. By determining activity of mushroom, the amount of Cs-137 in the ground can be estimated. In the fall of 2018, the interdisciplinary mass-experiment Strålande jord will take place with the purpose to map this amount all over Sweden. The purpose of this work was to reach results that could be of use when determining the activity of mushroom. A numerical tool for analysing data from gamma spectroscopy has been constructed. Two different methods for calculating counts in energy peaks from gamma emission spectra have been made and have been the basis for the further work. During this work the following has been determined: The efficiency of a high purity germanium (HPGe) detector, the activity of two different mushroom samples, the attenuation coefficient of gamma at 662 keV for these samples and for water. In order to be able to approximate a can filled with mushroom as an isotropic radiating point source and get accurate results, the activity measurements need to be carried out with a great distance between the sample and the detector. A consequence of this is that this approximation is only suitable for high-activity mushroom, which became evident when the activity of a low-activity mushroom could not be decided with decent statistics even though single measurements were carried out in almost a weeks time. Systematic errors are not considered during this work, only statistical uncertainties.

A majority of research within the field of energetic materials have been centered around the stable crystalline phase, whilst there has been less about the amorphous phase and the implications of these types of material. In this study, Molecular Dynamics simulations with the General Amber Force Field (GAFF) is used to predict fundamental properties of the nitramine explosives HMX and CL-20 in the amorphous phase. Amorphous structures are obtained by compressing a molecular gas to 4 GPa followed by relaxation and equilibration. The simulations indicate that the amorphous phases of HMX and CL-20 have lower densities than the corresponding crystal phases, 12.7% and 7.3% respectively. Both HMX and CL-20 was found to compress more easily when subject to external pressure, the difference was most significant for HMX.As a second part of this study an amorphous composition of CL-20/HMX/Polyvinylacetate(PVAc) (50/45/5 -wt%) was studied. This was obtained by compressing a molecular gas to varying pressures followed by relaxation and equilibration. Results indicate that the simulated density around 1.64 [g/cm3 ] fall close to experimental observations of 1.7 [g/cm3 ]. The density was observed to not vary significantly for pressures higher than 0.4 [GP a] in accordance to experimental data.

Ruthenium complexes has been geometrically optimized with different combinations of basis sets. Using single point calculation, the Density of States and partial Density of States has been calculated. RuIII-OH2 experienced a shift towards higher binding energies. The Ru atom plays a vast role in the contribution to the HOMO level of each complex, dominating in RuII-OH2. The nitrogen atom gives a small contribution for each complex in the HOMO region except for RuII-OH2 where it only appears at higher binding energies. The energy difference between RuII-OH2 and RuIII-OH/RuIV-O is about 1.1 eV whereas it experimentally is shown to be around 1.5 eV for the same complexes.

Optical frequency comb spectroscopy (OFCS) combines two previously exclusive features, i.e., wide optical bandwidth and high spectral resolution, enabling precise measurements of entire molecular bands and simultaneous monitoring of multiple gas species in a short measurement time. Moreover, the equidistant mode structure of frequency combs enables efficient coupling of the comb power to enhancement resonant cavities, yielding high detection sensitivities. Different broadband detection methods have been developed to exploit the full potential of frequency combs in spectroscopy, based either on Fourier transform spectroscopy or on dispersive elements.There have been two main aims of the research presented in this thesis. The first has been to improve the performance of mechanical Fourier transform spectrometers (FTS) based on frequency combs in terms of sensitivity, resolution and spectral coverage. In pursuit of this aim, we have developed a new spectroscopic technique, so-called noise-immune cavity-enhanced optical frequency comb spectroscopy (NICE-OFCS), and achieved a shot-noise-limited sensitivity and low ppb (parts-per-billion, 10−9) CO2 concentration detection limit in the near-infrared range using commercially available components. We have also realized a novel method for acquisition and analysis of comb-based FTS spectra, a so-called sub-nominal resolution method, which provides ultra-high spectral resolution and frequency accuracy (both in kHz range, limited only by the stability of the comb) over the broadband spectral range of the frequency comb. Finally, we have developed an optical parametric oscillator generating a frequency comb in the mid-infrared range, where the strongest ro-vibrational molecular absorption lines reside. Using this mid-infrared comb and an FTS, we have demonstrated, for the first time, comb spectroscopy above 5 μm, measured broadband spectra of several species and reached low ppb detection limits for CH4, NO and CO in 1 s.The second aim has been more application-oriented, focused on frequency comb spectroscopy in combustion environments and under atmospheric conditions for fast and sensitive multispecies detection. We have demonstrated, for the first time, cavity-enhanced optical frequency comb spectroscopy in a flame, detected broadband high temperature H2O and OH spectra using the FTS in the near-infrared range and showed the potential of the technique for flame thermometry. For applications demanding a short measurement time and high sensitivity under atmospheric pressure conditions, we have implemented continuous-filtering Vernier spectroscopy, a dispersion-based spectroscopic technique, for the first time in the mid-infrared range. The spectrometer was sensitive, fast, robust, and capable of multispecies detection with 2 ppb detection limit for CH4 in 25 ms. / Optisk frekvenskamspektroskopi (OFCS) kombinerar två tidigare icke förenliga egenskaper, dvs. ett brett optiskt frekvensområde med en hög spektral upplösning, vilket möjliggör noggranna mätningar av hela molekylära absorptionsband och detektion av flera gaser samtidigt med en kort mättid. Eftersom frekvenskammar har en regelbunden struktur med jämnt separerade laser moder kan man effektivt koppla kammen till en optisk kavitet och därmed möjliggöra frekvenskamsdetektion med hög känslighet. Olika metoder har utvecklats för att utnyttja frekvenskammarnas fulla potential för spektroskopi, baserad på antingen Fouriertransform-spektroskopi eller dispersiva element.Forskningen som presenteras i denna avhandling har haft två huvudmål. Det första har varit att förbättra prestandan hos mekaniska Fourier-transformspektrometrar (FTS) baserat på frekvenskammar med avseende på känslighet, upplösning och spektral täckning. I strävan efter detta har vi utvecklat en ny spektroskopisk teknik, benämnd brusimmun kavitetsförstärkt optisk frekvenskamspektroskopi (NICE-OFCS), och uppnått en hagelbrusbegränsad känslighet och detektionsgränser ner till låga ppb koncentrationer (miljarddelar, 10−9) för CO2 i det när-infraröda frekvensområdet enbart med användning av kommersiellt tillgängliga komponenter. Vi har också utvecklat en ny metod för insamling och analys av kambaserade FTS-spektra, som betecknas ha sub-nominell upplösning. Metoden gör det möjligt att uppnå ultrahög spektral upplösning och hög frekvensnoggrannhet (båda i kHz-området, endast begränsad av kammens stabilitet) över kammens hela frekvensområde. Slutligen har vi utvecklat en optisk parametrisk oscillator som genererar en frekvenskam i det mid-infraröda frekvensområdet, där de starkaste rotations-vibrationsmolekylära absorptionslinjerna finns. Med hjälp av denna kam och en FTS har vi för första gången demonstrerat frekvenskamspektroskopi över 5 μm. Vi har detekterat bredbandsspektra av flera molekylära gaser och har, för mättider på 1 s, uppnått detektionsgränser ner till låga ppb halter för CH4, NO och CO.Det andra syftet har varit mer applikationsorienterat: att använda frekvenskamspektroskopi i förbränningsmiljö och under atmosfäriska förhållanden för snabb och känslig multiämnesdetektion. Vi har för första gången demonstrerat kavitetsförstärkt optisk frekvenskamspektroskopi i en flamma, där vi har detekterat högtemperaturspektra av H2O och OH i det när-infraröda området med användning av FTS och visat teknikens potential för termometrisk karakterisering av flammor. För applikationer som kräver en kort mättid och hög känslighet under atmosfäriska förhållanden har vi utvecklat ett detektionssystem baserat på Vernier-spektroskopi med kontinuerlig filtrering, vilket är en dispersionsbaserad teknik, för första gången i det mid-infraröda frekvensområdet. Det befanns att spektrometern var känslig, snabb, robust och kapabel till multiämnesdetektion med en detektionsgräns på 2 ppb för CH4 för korta mättider (25 ms).

The Optical Frequency Comb Spectroscopy (OFCS) Group at the Department of Physics at Umeå University develops new techniques for extremely high sensitivity trace gas detection, non invasive temperature measurements, and other applications of OFCS. Their setup used primarily for trace gas detection contains several components that have been developed in-house, including a Fourier Transform Spectrometer (FTS) and an auto-balancing detector. This is the one used in this thesis work and it includes a high frequency data acquisition card (DAC) recording interferograms in excess of 10^7 double-precision floating point samples per sweep of the FTS's retarder. For acquisition and analysis to be possible in both directions of the retarder the interferograms needs to be analysed in a sub-second timeframe, something not possible with the present software. The aim of this thesis work has thus been to develop a system with optimized analysis implementations in MATLAB. The latter was a prerequisite from the group to ensure maintainability, as all members are well acquainted with it.Fulfilling its primary purpose MATLAB performs vector and matrix computations quite efficiently, has mostly fully mutable datatypes, and with recent just-in-time (JIT) compilation optimizations vector resizing performance has improved to what in many instances is perceived as equivalent to preallocated variables. This memory management abstraction, however, also means that explicit control of when arguments are passed by value or by reference to a function is not officially supported. The following performance ramifications naturally increase with the size of the data sets (N) passed as arguments and become quite noticeable even at moderate values of N when dealing with data visualization, a key function in system. To circumvent these problems explicit data references were implemented using some of the undocumented functions of MATLAB's libmx library together with a custom data visualization function.The main parts of the near real time interferogram analysis are resampling and a Fourier transformation, both of which had functionally complete but not optimized implementations. The minimal requirement for the reimplementation of these were simply to improve efficiency while maintaining output precision.On experimentally obtained data the new system's (DAQS) resampling implementation increased sample throughput by a factor of 19 which in the setup used corresponds to 10^8 samples per second. Memory usage was decreased by 72% or in terms of the theoretical minimum from a factor 7.1 to 2.0. Due to structural changes in the sequence of execution DAQS has no corresponding implementation of the reference FFT function as the computations performed in it have been parallelized and/or are only executed on demand, their combined CPU-time can however in a worst-case scenario reach 75% of that of the reference. The data visualization performance increase (compared to MATLAB's own, as the old system used LabVIEW) depends on the size in pixels of the surface it is visualized on and N, decreasing with the former and increasing with the latter. In the baseline case of a default surface size of 434x342 pixels and N corresponding to one full sweep of the FTS's retarder DAQS offers a 100x speed-up to the Windows 7 version of MATLAB R2014b's plot.In addition to acquiring and analyzing interferograms the primary objectives of the work included tools to configure the DAC and controlling the FTS's retarder motor, both implemented in DAQS.Secondary to the above was the implementation of acquisition and analysis for both directions of the retarder, a HITRAN reference spectra generator, and functionality to improve the user experience (UX). The first, though computation time allows for it, has not been implemented due to a delay in the DAC-driver. To provide a generic implementation of the second, the HITRAN database was converted from the text-based format it is distributed in to a MySQL database, a wrapper class providing frequency-span selection and the absorption spectra generation was developed together with a graphical front-end. Finally the improved UX functionality mainly focused on providing easy-access documentation of the properties of the DAC.In summation, though the primary objectives of optimizing the data analysis functions were reached, the end product still requires a new driver for the DAC to provide the full functionality of the reference implementation as the existing one is simply too slow. Many of DAQS' components can however be used as stand-alone classes and functions until a new driver is available. It is also worth mentioning that National Instruments (NI), the DAC vendor, has according to their technical support no plans to develop native MATLAB drivers as MathWorks will not sell them licenses.

This thesis presents the synthesis methods and the characterizations of magnetic Fe3O4 nanoparticles, silica spheres with Fe3O4 nanoparticles embedded, and three dimensional magnetic photonic crystals (MPCs) prepared from the spheres. The structure, material composition, magnetic and optical properties, photonic band gaps (PBGs), as well as how these properties depend on the concentration of the magnetic nanoparticles, are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), superconducting quantum interference device (SQUID), Faraday rotation (FR) and optical spectrophotometers. Well-organized, face center cubic (fcc)-structured, super-paramagnetic 3D MPCs have been obtained and their PBGs are investigated through optical spectra. Fe3O4 nanoparticles are synthesized by standard co-precipitation method and a rapid mixing co-precipitation method with particle size varied from 6.6 nm to 15.0 nm at different synthesis temperature (0°C ~ 100°C). The obtained Fe3O4 nanoparticles, which show crystalline structure with superparamagnetic property, are embedded into silica spheres prepared at room temperature through a sol-gel method using the hydrolysis of tetraethyl orthosilicate (TEOS) in a base solution with different concentrations. By controlling the synthesis conditions (e.g., chemicals, the ratio of chemicals and stirring time), different size of MPC spheres in range of 75 nm to 680 nm has been obtained in a narrow distribution. The sphere suspensions in ethanol are dropped on glass substrate in the permanent magnetic field to achieve well organized 3D MPCs with (111) triangular close packed crystal plane of fcc structure parallel to the surface of substrate. From the transmission &amp; forward scattering spectra (TF), five PBGs have been distinguished for these MPCs and they are defined as 1st, 2nd, 3rd, 4th and 5th PBGs according to the order of peaks that appear in mathematic fitting analysis. The positions (peak wavelengths) of PBGs show sphere size dependence: with the increase of the sphere size, they increase linearly. Comparing with pure SiO2 PCs at certain sphere size, the positions of PBGs for MPCs containing moderate Fe3O4 conc. (4.3 wt. %) are at longer wavelengths. On increasing the Fe3O4 conc., however, the PBGs shift back to shorter wavelength. The PBGs shift to longer or shorter wavelength is due to the combined effect of refractive index n increasing, as well as the increase of refractive index difference Δn, which are caused by the embedded Fe3O4 nanoparticles. The transmission spectra (T) with varied incidence angle of p- and s- polarized light are studied, obtaining angular dependent and polarization sensitive PBGs. It is found that with the increase of the incidence angle, the 1st PBGs shift to shorter wavelength while the 3rd ones shift to longer wavelength. High Fe3O4 conc. MPCs (6.4 wt. %) show enhancement of this angular dependence. It is also found that the PBGs show dependence on the polarize direction of incident light. Normally, at a certain incidence angle the PBGs sift more for p- polarized incident light than for s-polarized light with respect to normal incidence. This polarized dependence can also be enhanced for high Fe3O4 conc. MPCs. With a high concentration of Fe3O4 nanoparticles, the polarization sensitivity of p- and s- increased. These PBG properties indicate applications of 3D MPCs as functional optical materials, coatings, wavelength and polarization fibers for fiber optical communications devices and dielectric sensors of magnetic field, etc.. / QC 20110224