This PDF file contains the front matter associated with SPIE Proceedings Volume 11277, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

The importance of additive manufacturing for optical components and systems is steadily increasing. Conventional 3D printing processes such stereo lithography (STL) are used to realize passive optical components. The challenge is thereby the surface quality and the volume scattering of the components produced. Irrespective of this, 3D printing of passive optical components has a wide variety of application fields, especially for illumination. The next step in additive manufacturing of optics is to achieve a higher functionalization of the components, thus turning form passive optical components to active optical systems.

Thereby, it is an exciting and challenging question, if one can 3D print a laser completely additive. Therefore, we tried two different approaches. The first approach is comparable to a plastic optical fiber amplifier. For this purpose, laseractive nanoparticles (Nd-YAG) were incorporated into a resin and 3D-printed using a STL system. Due to the DLP projector of the STL system, one can realize a periodic change of the refractive index within the printed sample. Thus, the 3D printed cavity is comparable to a bundle of several thousand active fibers (given by the resolution of the projector). In this way, a POF amplifier was realized. The creation of a 3D printed resonator out of this is challenging and will be discussed. Alternatively, we realized a random laser with the aid of additive manufacturing. For this purpose, we mixed the printing material with Rhodamine and nanoparticles. Finally, the laser was 3D printed. We will discuss the performance of this device as well.

Organic Light Emitting Diodes (OLEDs) are a promising alternative to conventional anorganic semiconductor devices. Especially in terms of manufacturing, new technologies promise a variety of new opportunities. 3D printing processes are able to deposit functional materials on additive manufactured surfaces with simultaneously low material consumption. Furthermore, this may be implemented in conventional 3D printing to achieve a functional process. With this technology it is for example possible to manufacture a fully additive manufactured illumination system, based on polymer OLEDs. We use solvable functional inks for each semiconductor layer, which are ready to use in inkjet printing systems. Here we present the transfer from commonly used anorganic ITO (indium tin oxide) to an inkjet printed, transparent anode on an additive manufactured resin substrate. In addition, we discuss the 3D printing technologies involved in the manufacturing process as well as the geometrical layer design and contacting methods used. Challenges here by are the surface quality and wetting properties of the substrate surface and each individual layer. We evaluate our results by the electrical and optical characteristics. Additionally we discuss manufacturing parameters and their effect on the device functionality.

Analysis of a 3D printed chip from different quantum dot nanocomposites capable of multiple wavelength photoluminescent emission has been presented. The optical analysis of the result includes the minimization of photoluminescence scattering in arbitrary directions from the chip via structural modifications to the chip design. Other challenges include unwanted transmission of the Quantum Dots UV excitation via photopolymer chip base, contaminating the specimen on the chip. Comments on the feasibility of using this chip as a cheap alternative for narrow-spectrum, multi-wavelength light source for spectrometric analysis of photosensitive samples, have been made, especially with respect to the lifetime and stability of photo luminescence.

Organic room temperature phosphorescence (RTP) is used to realize rewriteable (>40 cycles), transparent and flexible optical tags with high resolution (>700 dpi). The devices contain an organic biluminescent emitter doped into polymethylmethacrylate (PMMA). They show phosphorescence, which in general is quenched by molecular oxygen. However, by illuminating with ultraviolet light (365 nm), this molecular oxygen locally vanishes at the irradiated area, enabling RTP at defined spots. Further, by illuminating with infrared light, the system can be refilled with oxygen leading to quenching of the RTP again. Therefore, any luminescent pattern can be written into and erased from the tag using light only.

Measuring the photoluminescence quantum yield (PLQY) is a method often used within numerous fields of luminescent material science. Determining its absolute value relies on counting photons and hence, it is a very sensitive technique. Therefore, systematic errors that may occur during the measurement are discussed widely. However, the statistical uncertainty within those measurements remains mainly unconsidered. Here, we propose a new way of data analyses that exploits multiple measurements and a subsequent evaluation using the weighted mean. This leads in an efficient way to a very low statistical uncertainty. Additionally, time-dependent influences on the measurement can be identified that way.

We present a new phase separation phenomenon “nanophase separation”, which occurred in comb-shaped polymers. We have found that comb-shaped polymers such as poly(alkyl acrylamides) and poly(alkyl acrylates) formed a highly oriented lamellar structure by annealing the film under humid condition. The effect of temperature and humidity to the lamellar formation suggested that the nanophase separation, which is the phase separation between alkyl side chains and main chain is the driving force for the lamellar formation. We combined the nanophase separation to the microphase separation in block copolymer to prepare a vertically aligned nanocylinder film.

Moth-eye surfaces can prevent reflection with minute unevenness structure of nanometer size. A nano-imprinting process, which generates minute patterns of polymers using a mold, is a promising candidate for a high-throughput patterning process. In the present report, first of all, I describe the nano-imprinting processes based on the highly ordered anodic porous alumina. Anodic porous alumina, which is formed by the anodization of Al in acidic solution, is a typical naturally occurring ordered material. The Anodic porous alumina can be formed even on the curved surface. We have been researching a continuous manufacturing process of the moth-eye surfaces on polymer films with the roll molds. Second, I mention optical characteristics of the moth-eye surfaces. Third, I report multi-functionalities of the moth-eye surfaces.

Self-assembled nanoparticle (NP) clusters exhibit unique electromagnetic responses and have attracted considerable interest due to their potential for controlling colors, refractive indices, and electromagnetic enhancement via the strong interaction between light and matter. Surface-enhanced Raman scattering (SERS) from molecules adsorbed on the nanoparticle clusters is one of the notable properties of NP clusters. In this report, gold NP clusters based on polymer core−shell particles incorporating magnetic iron oxide NPs were prepared via a self-assembly method.The enhancement factor of the SERS signal was determined by the size of composited gold nanoparticles.These composite particles are expected to be applicable to the is situ SERS analysis of chemical species in chemical reaction media and biological samples.

Near-infrared luminescent lanthanide (Ln)-doped nanomaterials are currently attracting high interest in view of their sharp f-f emission peaks and long luminescence lifetimes, which establish a unique value for the development of optical amplifiers, lasers and biosensors. To improve the optical pumping of the weakly absorbing lanthanide ions (Ln³⁺), the doped nanoparticles are coupled with an organic dye sensitizer able to efficiently harvest light and subsequently transfer the absorbed energy to the emitter. However, this through-space “remote” sensitization is severely subjected to energy losses due to competitive energy migration or deactivation routes limiting the overall luminescence quantum yields. The implementation of the Förster’s model of resonance energy transfer on the basis of advanced ultra-fast transient absorption and photoluminescence spectroscopy with the support of density functional theory calculations demonstrate that the sensitization efficiency from the dye to the doped nanoparticle is strictly regulated by the geometry and localization of the transition dipole moment of the dye molecule. Within the nanoparticle, the energy transfer pathways can be harnessed through the spatial confinement of ‘energy bridges’, accepting energy from the surface dyes and donating to core emitters. We show that the FITC (fluorescein-isothiocyanate) dye allows reaching exceptional sensitization efficiency close to unity for the NIR-emitting triad Nd³⁺, Er³⁺ and Yb³⁺.

Transparent photothermal (PT) materials absorbing NIR light have attracted strong interest for wireless soft robots, photothermal therapy, sensors, and wearable optoelectronic devices. Since PT materials convert light energy to heat energy, they can function as highly programmable wireless heaters and PT actuators, depending on the intensity and wavelength of the light source. However, transparent PT materials have been rarely researched because of the difficulty in absorption separation between the visible and NIR region in a molecule. Furthermore poor solubility of NIR dyes limit their application as a transparent film. Herein we present a transparent NIR dye having a transparency at visible region over 90 %. With a transparent binder, the NIR dye was fabricated as an NIR absorbing film, which showed high NIR photothermal conversion efficiency over 75 %. Taking advantage of the high photothermal effect of the film, we were able to generate a transparent photothermal heater that could be applied into desalination and actuation. The mechanism and application potential for the photothermal effect will be discussed based on the optical properties of the NIR dyes.

Norbornene-dicarboximide (NDI) has been selected to be utilized as promising alternative for electro-optic (EO) application. Herein, NDI unit was incorporated to hexyl as well as FTC chromophore substituent for controlling thermal-physical properties and achieving EO activity, respectively. NDI monomers with different pendants were thoroughly polymerized to obtain EO copolymers with high EO chromophore loading density, appropriate molecular weight, as well as high glass transition temperature. This work will be discussed about the EO polymers with distinct design and its effect to physical properties and device characteristics.

In the present study, we fabricated novel electro-optic (EO) phase modulators using EO polymer waveguides and gold antenna arrays for continuous-wave terahertz (THz) detection. We used a cyclo-olefin polymer (COP) with very small absorption losses and low dielectric constants in the THz region as a substrate, enabling relatively large antenna size with small absorption loss for increasing modulation efficiency. By irradiating W-band (75-110 GHz) electromagnetic waves on the devices, we observed modulation sidebands in the measured optical spectra and successfully demonstrated the electromagnetic wave detection.

The effects of incorporation into a solid matrix on the photophysical properties of a nonlinear material have been of interest for some time in our group. It is well known in the literature that for a nonlinear absorbing dye to be the most effective, high concentrations are generally needed. Understanding how the larger concentration and placement into a solid matrix affects their photophysical properties is the key of this study. Here we look at two metallated substituted tetrakis(cumylphenoxy) phthalocyanines with either Pb or In as the central metal. A detailed study of their photophysical properties based on concentration allows for a better understanding of the constraints this environment has to a given material.

Here, we present our development of several experimental methods, which, when applied together, can provide a thorough characterization of the nonlinear refraction and absorption properties of materials. We focus mainly on time-resolved methods for studying both transient absorption and refraction that reveal molecular dynamics including excited-state absorption, singlet-triplet transfer, instantaneous electronic nonlinear refraction, and molecular reorientation. In particular, we will describe our recent studies of new materials including organometallic compounds and organic solvents such as Tetrachloroethylene (C₂Cl₄).

We demonstrate transmission of 43-Gb/s NRZ optical signals through a 2.3-cm-long single-mode polymer waveguide at the eight wavelengths of the Local Area Network Wavelength Division Multiplexing (LAN-WDM). The polymer optical waveguides have a propagation loss of 0.4 dB/cm and a polarization dependent loss (PDL) of less than 0.5 dB over the entire O-Band (100 nm wide from 1260 to 1360 nm). The coupling loss between the polymer waveguide and a single mode fiber is 0.5 dB/facet. Error-free optical transmission at the data rate of 43- Gb/s was achieved without noticeable penalty in all the LAN-WDM channels ranging from 1273.55 to 1309.14 nm. To investigate the possibility of high-capacity WDM transmission that utilize eight optical signals with different wavelength, we also studied the performance of the polymer waveguide at high input powers. First, we observed that there is a linear relationship between the input power and the output power with the input light power of up to 90 mW. This observation shows that the polymer waveguide has a high damage threshold against high input power and there is no excess loss caused by thermal effect. Second, we assessed the nonlinear optical effect of the polymer waveguide by launching an ultrashort optical pulse with a peak power of 500 mW and observed no signal distortion due to cross phase-modulation (XPM) or four-wave mixing (FWM). These results suggest the polymer waveguide is potentially available for high-capacity data transmission at 344 Gb/s or more by 8-channel LANWDM.

Transient absorption (TA) measurements on nanosecond through microsecond time scales were performed on solutions of tris(2,2'-bipyridine)ruthenium(II) and anthracene in various relative concentrations. Following energy transfer from the ruthenium trisbipyridine sensitizer, the anthracene acceptor undergoes dimerization, which has been shown to occur via triplet-triplet annihilation. Values of the associated rate constants were determined by fitting the experimental TA data to the nonlinear kinetic model implied by the law of mass action. We report values of 6.9 × 10⁸ liter mol⁻¹ s⁻¹ and 7.9 × 10⁹ liter mol⁻¹ s⁻¹, respectively, for the rate constants for energy transfer and for anthracene dimerization.

We present our recent research results on luminescence of halide perovskites under various excitation sources: photoexcitation, electrical current and high-energy radiation. Our photonics crystal can reduce the emission rate of perovskite film by preventing the photoluminescence coupling to the film, but enhance the out-coupling efficiency by 23.5 times. Our solution-grown single-crystal perovskite hetero-structure was successful with different halide compositions. A pristine single-crystal light emitting device was demonstrated with excellent protection and encapsulation from material synthesis to device characterization. Lastly, with engineered perovskite materials we demonstrate a multifunctional scintillator for high-energy radiation from X-rays, gamma rays to thermal neutrons.

Hybrid organic-inorganic halide perovskites are the most promising materials for photovoltaic applications and especially low-cost, high-efficiency solar cells. Application these promising materials as absorbing thin films inside solar cells caused rapid increase of the power conversion efficiency even above 20% as well as research explosion. Theoretical and experimental investigations are primarily focused on unique electronic properties of these materials result including high carrier mobility, low carrier recombination rates and tunable spectral absorption range. The application field of hybrid perovskites has quickly expanded in terms of the types of materials by substituting one or more of the organic or inorganic ions in one of the most studied perovskites, to obtain the metal halide perovskites AMX₃. However, most of the work focused on optimizing the components of solar cells, namely absorbing range of the material and charges collection form the solar cells structure. In contrast, the influence of the technical factors on the device fabrication has been much less explored. This applies especially to techniques for manufacturing multi-layer structures using high vacuum environment, although undoubtedly these techniques allow obtaining the highest quality tin films. This work contains investigation results of the structural properties of the AMX₃ perovskites thin films and their influence on the electrical properties multilayer structure of the solar cells. Organic-inorganic AMX₃ halide perovskites containing methylammonium lead iodide (CH₃NH₃PbI₃) thin films are used for experimental investigations.

Due to the large exciton binding energy, two-dimensional perovskite has demonstrated the potential as high-performance while low-cost scintillator. In our experiment, first we systemically investigate the effect of Li-ion dopant in phenethylammonium lead bromide, (PEA)2PbBr4 perovskite crystals under soft X-ray radiation of 15 keV. Successful inclusion of Li at four doping concentrations was confirmed by X-ray photoelectron spectroscopy. Li doping causes no substantial change in the crystal structure judging from the X-ray diffraction pattern but induces stronger emission tail as observed in the temperature-dependent X-ray luminescence (XL). Upon higher Li concentration, the emissions become broader due to possible Li trap emission as indicated by increasing traps induced by more Li in the X-ray thermoluminescence spectra. The behavior of negative thermal quenching is found in the XL and it can yield a benefit such as the possible light yield improvement in the X-ray imaging application. After the soft X-ray characterizations, we further explore our crystals in gamma-ray detection. In the gamma-ray pulse height measurement, relatively broad peaks can be resolved with the light yield of about 10,000 photons/MeV at 662 keV. The result from alpha particle pulse height measurement also indicates that we could even utilize our crystals in alpha particle detection at 5.8 MeV. Based on this feature and Li-ion capability as dopants, our crystals promise a good performance in thermal neutron detection. Finally, we can realize a versatile radiation detector that works in broad range of energy from soft to high energy radiation.

Biopolymers, including deoxyribonucleic acid (DNA) and nucleobases, have unique electromagnetic and optical properties, such as low optical loss, low electrical resistivity and large bandbap, which make them ideal for use as charge carrier blocking layers. Applications include, organic light emitting diodes (OLEDs), polymer dielectric capacitors, and nonlinear (NLO) polymer electro-optic (EO) modulators. They have demonstrated increases in device performance, by as much as 3X-6X, for all three applications. This significantly reduces the constraints on developing new organic LED, polymer dielectric and NLO polymer materials. The most recent results of this work will be presented at the conference.

Time-resolved circular dichroism (TR-CD) is a powerful tool for probing the conformational dynamics of molecules over large time-scales. By using Binaphthol and two bridged derivatives (PL1 and PL2) as chiral prototypes, we present the first comprehensive study of this type in the middle UV, combining femtosecond TR-CD and quantum mechanical calculations (TD-DFT). We show that excitation of the three compounds induces large variations of their transient CD signals, in sharp contrast to those of their achiral transient absorption, which arise both from the alteration of the electronic distribution and the change of the dihedral angle in the excited state.

This presentation will illustrate our different recent approaches in order to fulfill main requirements for in vivo bio-imaging. We will present our results based on : (1) molecular engineering approaches for enhancing organic based chromophores biphotonic properties and further spectroscopic requirements in the NIR1 ; (2) methods of hydrosolubilisation and biocompatibility for these biphotonic chromophores2 .Intravital fluorescence imaging or photodynamic therapy will be then discussed as a function of chromophores characteristics.

Disk lasers offer the beneficial properties of low thermal lensing, excellent heat dissipation, and the amplification of ultrashort pulses. Biomaterials can be used to produce flexible and wearable devices due to their suitable mechanical characteristics and non-toxicity. In this study, we demonstrate biomaterial disk lasers using the suppression of the coffee stain effect. They show whispering gallery mode laser emission with low threshold levels below 10 nJ/µm2. Their modes and threshold levels are controlled by varying the size of the disks. They are transferrable on curved surfaces and still continue their operation on those surfaces.

Organic light-emitting diodes (OLEDs) suffer from strong electrothermal feedback when operated with high currents. The interaction between conductivity, heat and power dissipation results in a positive feedback loop. When running an IV scan, former modeling revealed a so-called “switched-back” region where the local current density and brightness decreases although the total device current still increases. Here, we prove the existence of a switched-back region. We demonstrate that its appearance agrees with the simulation that solely uses electrothermal modeling. Our study aims to improve the long-term stability of high brightness OLED lighting tiles e.g. as applied in the automotive sector.

In recent years, PPDT2FBT is getting researchers’ attention due to its applications in solar cells and optoelectronic devices. Although the main applications of this material are based on the optical properties. However, the optical dispersion of this material has not been studied yet over the UV and visible spectral range. We report the optical properties of PPDT2FBT for the wavelength range of 300 nm to 900 nm using a variable angle spectroscopic ellipsometry (SE). The refractive index (n) and extinction coefficient (k) of spin coated PPDT2FBT thin films were determined at room temperature. Glass of known optical properties was used as the substrates for convenience. To build an optical model the surface morphology was studied using atomic force microscopy (AFM). Then an optical model was developed based on the extracted properties. The optical properties were found to be consistent with the UV-Vis data. The bandgap was estimated from the absorption properties. Finally, the developed ellipsometry model was used for thickness measurement of PPDT2FBT thin films. The measured data agreed well with the data collected using other direct thickness measurement techniques of the same thin film. This developed model can be useful for designing effective optoelectronic devices as well as measuring the thickness of thin films in a nondestructive way.

The research found the alternative optical properties of the firefly eye from its crystalline cone. The eye of the firefly has the periodic indices of refraction and configuration of 190 parabolic layers as a one-dimensional photonic crystal on the optical axis treated ommatidium of the firefly. The paper performed anatomy of the firefly eye to reveal the structural compound eye of the firefly and simulated a dioptric portion of the firefly eye. The results realized the behavior of the visual output according to the optical raytracing by using geometric optics. The research applied the transfer matrix to observe the transmission efficiency and found that there exists the filtering capability on the optical axis. Based on the incident of collimating light, the efficiency of the superposition eye is higher than that of the apposition eye, by more 900 times.

This work shows the development of a fiber optic taper machine by applying a controlled melting temperature, which is induced by a 30W CO₂ laser. The laser is made to influence the fiber, heating it and making it malleable. Then the tension axis of the device moves, having three independent axes X, Y and Z on the laser system, it is possible to mark the fiber in order of generate gratings. The device was designed entirely with low-cost materials, which are made for process optimization, such as resources. The software implemented is designed in Arduino for an IOT card that operates with HTML interface, is controlled from a website with which different variables can be handled for the operation of the taper machine, such as distance, speed and time. The device is controlled by means of Wi-Fi, through a website generating accessibility to the free operation of the engines, which can be executed over the same network. The machine has an aluminum base on which are two endless screws, connected each to a step-by-step motor that when turning in opposite directions move each one, a Fiber Holding Blocks on which the fiber is held to be stretched. The electronic circuit is located in a box attached to the motor system.

Multi-mode planer optical waveguides have been fabricated on PDMS coated glass substrate using off stoichiometry thiolene- epoxy (OSTE⁺) polymer thin film, by an optical photolithography technique. The light wave-guiding phenomena has been observed in this novel OSTE⁺ polymer waveguide using prism coupling method. Four discrete propagating optical modes have been observed, upon monochromatic light (635 nm) excitation. These modes were recorded using a USB camera at different angular positions. The evanescent wave absorption of these modes has been exploited for refractive index based photonic sensing applications.