This PDF file contains the front matter associated with SPIE Proceedings Volume 11165, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists

We live in a world in flux with technology changing at a pace unprecedented in human history. Over the past decade, a powerful wave of innovation based on digital platforms and apps has arisen due to their wider dissemination in our hyper-connected world. In the next decade, “deep” technologies will play a major role in pushing further the technological frontiers. Deep-tech innovations lie at the crossroads of massive shifts in demand led by megatrends (such as global climate change, demographic shifts, resource scarcity) and scientific progress (such as the fusion of the physical, digital and biological domains). Deep technologies are disruptive solutions built around unique, protected or hard-to-reproduce technological or scientific advances. In that next wave of innovation, advances in new materials and processing methods will continue to play a central role. In this talk, we will discuss how printable organic conjugated semiconducting molecules and polymers are creating new disruptive technologies that are impacting all industries. We will present recent advances in various solid-state device platforms including, organic light-emitting diodes (OLEDs), organic photodetectors (OPDs), organic photovoltaic devices (OPVs), and organic thin-film transistors (OTFTs). We will emphasize the importance of interfaces in devices and show examples on how to engineer their electrical properties. We will present a simple processing technique for the electrical doping of organic semiconductors over a limited depth near the surface of the film that is based on immersing the film into a polyoxometalate solution. Such approached can drastically reduce the fabrication cost of such devices, simplify device architecture, and lead to all-organic devices fabricated by all-additive printing techniques. As an illustration of the simplicity and versatility of this process we will discuss how high-performance organic solar cells with simplified architecture can be implemented. Finally, we will present the results of a detailed operational lifetime study of OTFTs showing that organic photonics and electronics can yield a stability level superior to that of amorphous silicon.

Due to advances in the heat seeking technology combat loses from heat seeking missiles have exceeded 95%. That is why today the need for compact, broadly tunable mid and longwave IR sources for IR countermeasures is more urgent than ever. Laser radar, high speed IR communications and remote sensing of chemical and biological agents are other military and security applications of such sources. Many other commercial applications in areas such as environmental sensing, industrial production, spectroscopy and medicine also encourage their development. The existing direct laser sources in these wavebands have low output power, limited wavelengths and poor tunability. That is why efforts into development of frequency conversion devices, especially those that are based on quasi-phase matching have been made to provide alternatives. In non-polar materials frequency conversion can be achieved in thick periodic structures grown on OP templates. In this work we report several studied OP materials, the most mature of which is OPGaAs where we have achieved 60% conversion efficiency. We show how these materials achieve their limits bringing us to the idea of combining them by heteroepitaxy (especially when native substrates are unavailable) or by growing ternaries attempting to combine their best NL properties. For example, GaAs exhibits strong two-photon absorption (2PA) in the convenient pumping range of 1–1.7 µm, which easily deteriorates the OPGaAs device performance. Replacing GaAs with GaP, which nonlinear susceptibility is similar but its 2PA in the same frequency range is with 3 orders of magnitude lower, is soon followed by disappointments related to the high price and low quality of the commercially available GaP substrates. Fortunately, the attempts to grow heteroepitaxially GaP on GaAs and OPGaP on the high quality OPGaAs templates led unexpectedly to good results in spite of the relatively large lattice mismatch (-3.26%) between GaP and GaAs. More heteroepitaxial cases (some more favorable) such as ZnSe/GaAs (+0.238 %), α-GaSe/GaP (-0.607 %), etc. were also attempted, leading by the fact that in some of these cases large enough crystalline substrates are not available. Although that the state-of-art results – smooth surface morphology (1-2 nm in 5x5 µm AFM scanning spot), high crystalline quality (XRD: FWHM within 50-60 arcsec) and excellent domain fidelity for the growth on OP-templates were achieved with the GaP/GaAs growths, growth of ZnSe/GaAs may also be considered as successful (with the remark that the high vapor pressure of the Zn-source restricts the duration of growth. There is much more to ask for the growths of GaSe where the growth of the cubic α-phase GaSe/GaP were more successful than the growth on the hexagonal β-phase GaSe/GaN. High resolution TEM images of the interface allowed to learn more about the growth mechanisms. For example, during fast growth processes (HVPE) the strain built due to the lattice and the thermal mismatch relaxes faster by formation of voids or roughening of surfaces, which may postpone the formation of the typical misfit dislocations observable during slow growths (MOCVD, MBE). All this allowed to predict success for other heteroepitaxial cases – for instance ZnTe/GaSb.

The widespread usage of harmful pulsed laser sources emitting brief but intense radiations implies to search for appropriate and convenient forms of protection. Nonlinear optical nanomaterials can serve this purpose when properly embedded in a solid medium, resulting in nanohybrid passive optical limiting filters. This work focuses on the optical limiting behavior of polymer-dye nonlinear nanohybrids, for which we combined azophloxine, a red azo-dye, with two polymer hosts, namely PMMA and polylactide (PLA). Transmittance measurements in the nonlinear regime were performed at the wavelength of 1064 nm with nanosecond pulses at a low pulse repetition rate. The nonlinear optical properties resulting from energy dependent transmittance assessments reveal that the dye concentration is of major relevance regarding the PMMA nanohybrids, and to a lesser extend for the PLA based systems. The PLA synthesis concept described in this study offers an easy way to directly attach the dye covalently to the polymer chain. The originality and novelty of this synthesis technique is to be pointed out since it has never been mentioned elsewhere to date. For the various types of nanohybrids investigated, significant differences in the optical limiting response were observed. A molecular model claiming for the dye aggregation in the PMMA nanohybrids is discussed. Two different absorption regimes responsible for the optical limiting action have been identified to be reverse saturable – excited state absorption on the one hand and multi-photons absorption on the other hand.

The receptive field of a visual neuron is the particular region in which a stimulus will modify the firing of that neuron. Retinal ganglion cells have a coaxial-shaped structure formed by the central excitatory and outer inhibitory regions. These regions respond oppositely to light. This shape can be mathematically modeled by a balanced Difference of Gaussian (DOG) function. In digital image processing, the DOG filter is used for detecting objects' edges. Bacteriorhodopsin (bR) is a photosensitive protein which resembles the visual pigment rhodopsin. When bR is illuminated, it generates a positive transient photocurrent, and, when light is switched off, a negative transient photocurrent is produced. This peculiar behavior is similar to the response of ganglion receptive fields. In this study, we fabricate a two-dimensional binarized DOG (b-DOG) filter, in which the central part mimics the excitatory part of the ganglion cell receptive fields, whereas the outer ring reproduces the effect observed in their outer inhibitory regions. This filter consists of photosensitive protein bR films and electrolyte solution that are sandwiched between ITO electrodes. To analyze the spatial-temporal frequency sensitivity, we use moving sine wave gratings with different pitches with a controlled scanning speed. When the temporal frequency is kept constant, the spatial frequency sensitivity matched with the Fourier transform of the b-DOG function. On the other hand, when the spatial frequency does not vary, the temporal frequency sensitivity corresponded well with the Fourier transform of Difference of Gamma function. Difference of Gamma function is known as the impulse response of the visual nerve of animals. We separately analyze the independent spatial and temporal frequencies collected from the spatial-temporal characteristics of the filter. The spatial-temporal frequency characteristics of b-DOG filter are similar to those of the X-type retinal ganglion cells. However, unlike the retinal ganglion cell, the b-DOG filter is a perfect linear filter. The analog image processing using this b-DOG filter is performed by scanning a standard test image. It is found that an edge can be detected just by scanning the image and plotting the zero-crossing point. With increasing input image size, the spatial frequency peak detected by the b-DOG filter shifts towards higher frequencies. Since there are only sharp edges where high spatial frequency components are present, the detected results of the analog filter are similar to that of the digital filter. Consequently, the phase difference between the input and output image is approximately the same for all pixels, and it agrees with the digital edge detection results. Some illusion images are scanned on the b-DOG filter to verify the occurrence of the illusion similar to vision. The Hermann grid illusion generated with lower-order vision was observed. It is found that no luminance information is necessary for the Herman grid illusion, because this b-DOG filter does not extract image luminance. The visual function elements similar to X-type retinal ganglion cells prepared in this study are useful to constructively understand the visual information processing mechanism of the organism.

Electrochromism (EC) is defined as reversible color change caused by electrochemical redox reactions. EC display has various advantages comparable to conventional displays, such as high visibility under sun light, a memory effect, and color variation. EC display has been attracting significant interest for strong candidate in information displays such as electronic paper (E-paper). We reported Ag deposition-based EC device which showed reversible color change from transparent to chromatic coloration, black and silver-mirror in a single device. Also, by improving voltage-application sequence, three chromatic color such as magenta, cyan and yellow have been successfully observed in the Ag deposition–based EC device in our previous study. This is due to the localized surface plasmon resonance (LSPR) of Ag nanoparticles deposited on the electrode. Namely, LSPR band is known to change its absorption wavelength depending on the size and shape of the nanoparticles. In this study, this device newly enabled us to achieve green coloration and we analyzed relationship between optical properties and morphology of silver nanoparticles at four chromatic states with theoretical calculation.

This work explores additive manufacturing technology to fabricate hybrid circuits comprising of optical and electronic materials as photonic and electrical interconnects, respectively. Several polymeric optical materials have been investigated (including SU8, PDMS, UV15 and Norland adhesives) as waveguides directly printed on commercial circuit boards such as FR4 and Rogers TC600. An optical waveguide printed over RF (radio frequency) transmission lines and surface mount electronic components is demonstrated. As an application, the waveguide is used as an alternative to traditional electrical interconnects to control an RF switch for routing an RF signal from a single source to different locations. This work also investigates the feasibility of printed polymeric waveguides as a sensing platform for monitoring humidity and temperature changes in electronic circuits. Results show that the SU8 waveguide responds significantly to change in temperature and humidity and the response is appropriate for logistics applications such as cold chain supply.

In this study, we present the results of copper azide Cu(N₃)₂ initiation by pulsed lasers. The threshold energy and energy density are defined. A comparison of the obtained results shows the similarity of initiation of silver azide and copper azide. An approach to improving the safety of the use of cooper azide is proposed.