Optical devices hybrid

Nonlinear Optical Devices. A transparent, optically active, sol—gel-derived organic—inorganic glass has been synthesized (68). This hybrid consists of a 2,4-dinitroaminophenylpropyl-triethoxysilane covalently bound to a siUcon alkoxide-derived siUca network. This hybrid exhibits a strong electric field-induced second harmonic signal and showed no signs of crystallization. 

Hybrid polymer silica nanocomposites formed from various combinations of silicon alkoxides and polymers to create a nanoscale admixture of silica and organic polymers constitute a class of composite materials with combined properties of polymers and ceramics. They are finding increasing applications in protective coatings (Figure 7.1), optical devices, photonics, sensors and catalysis.1... 

Kim et al. used the exchange reaction to synthesize cross-linked AuNP-PNIPAM core-shell hybrid structures, as well as a brush-type AuNP/PNIPAM hybrid through surface-initiated ATRP in an aqueous medium. The disulfide initiators, [BrC (CH3)2COO(CH2)iiS]2, were bound to AuNPs synthesized by citrate reduction. They have studied the effect of cross-linking on the thermo-responsiveness of the AuN / PNIPAM hybrids for potential use as a stimuli responsive optical device, such as surface plasmon resonance-based sensing materials [91]. 

UV light induced refractive index change has been observed in organic polysilane (PS)-silica and PS-titania hybrid thin films prepared by the sol-gel method.135 The magnitude of the refractive index change was found to be 0.16 for 50 wt % PS-silica and 0.18 for 50 wt % PS-titania hybrid thin films. It was demonstrated that the refractive index change of the hybrid thin films is due to the photodecomposition of PS. These findings indicate potential usefulness of the hybrid thin films as optical devices with refractive index modulated structures. 

Applied substrates require homogeneous and planar surfaces. Planar supports allow accurate scanning and imaging, which rely on a uniform detection distance between the microarray surface and the optical device. Planar solid support materials tend to be impermeable to liquids, allowing for a small feature size and keeping the hybridization volume to a minimum. Flat substrates are amenable to automated manufacture, providing an accurate distance from photo masks, pins, ink-jet nozzles and other manufacturing implements. The flatness affords automation, an increased precision in manufacture, and detection and impermeability. Table 1 shows frequently used support materials... 

In a somewhat similar fashion, Ishii et alP- have demonstrated inkjet fabrication of polymeric microlenses for optical chip packaging. UV curable epoxy resin is deposited onto optical devices by inkjet printing. When the droplets hit the surface, they form into partial spheres due to their surface tension, and are UV-cured to form the microlens with diameters from 20 to 40 tm with /-numbers of 1.0 to 11.0. Their uniformity in a microlens array was measured to be within 1% in diameter and 3 tm in pitch (total count of 36 lenses). They have also demonstrated hybrid integration of inkjetted microlenses with a wire-bonded vertical-cavity-surface-emitting laser (VCSEL) with coupling efficiencies of 4 dB higher than without the microlens. 

Apart from the tuning of the host-guest interactions, the elaboration of efficient optical devices also relies on the optimization of the matrix mechanical properties and thermal stability. This is clearly demonstrated in the development of hybrid materials for NLO, and especially second harmonic generation (SHG). These properties rely on their noncentrosymetric organization of organic chromophores in the condensed phase. Becanse incorporation in a silica... 

In this chapter, the development of NLO polymers with thin film or channel waveguide structures directed toward practical optical devices will be discussed. All optical signal processing polymers and electro-optical polymers are presented. Hybrid polymer optical devices for future applications will also be presented. 

Yu et al. (2003) synthesized hybrid thin films containing nanosized inorganic domains from poly(acrylic) and monodispersed colloidal silica with bound 3-(trimethoxysilyl)propyl methacrylate (MSMA) for potential applications as passive films in optical devices. The latter was polymerized with acrylic monomer to form a precursor solution, which was spin-coated and cured to form hybrid films. The silica content in the hybrid thin films was varied from 0 to 50 wt% (Figure 1.302). The coverage area of silica particles by the MSMA decreased with increasing silica content and resulted in the aggregation of silica particles in the hybrid films, and the silica domains were 20-35 nm in size. 

Bistable optical devices can also be constructed in such a way that the transmitted light signal is converted to an electrical voltage that is used to control the refractive index of the material inside the cavity. These hybrid optical-electrical devices can operate with very low levels of light intensity and as such are especially compatible with integrated optical components. 

Fig. 1 Various functional coatings onto porous silicon surfaces (a) thermally responsive polymer/porous silieon hybrid for biosensing (Perelman et al. 2010), (b) porous sihcon/polymer nanoeomposite for biosensing (Li et al. 2005), (c) BSA protein-adsorbed porous silicon surface (Tay et al. 2004), (d) diamond-eapped porous silicon film for optical devices (Fernandes et al. 1999), (e) biocompatible polymer/porous silieon eomposite fiber (Kashanian et al. 2010), (f) block copolymer-coated surface for templating (Qiao et al. 2007), (g) ZnO-deposited porous silicon (Kayahan 2010), (h) SERS active silver-coated porous silicon (Virgaetal. 2012) (Reproduced, with permission, from Perelman et al. (2010), Li et al. (2005), Tay et al. (2004), Fernandes et al. (1999), Kashanian et al. (2010), Qiao et al. (2007), Kayahan (2010), Virga et al. (2012))...

In this letter we show that if a hybrid aligned (HAN) cell is used an intensity-dependent refractive index can be obtained even with 0 = 0, for optical field amplitude practical application for those optical devices that might use self-focusing to get bista-... 

We have presented a discussion of the theories and experiments on laser-induced optica nonlinearities and some recently observed wave-mixing processes in nematic liquid crystals based on the phase grating induced by two laser pulses. These studies have demonstrated again the unique and interesting physical characteristics of liquid crystals that have attracted the attention of fundamental and applied researchers alike. It is also clear that some practically useful nonlinear optical devices could be constructed. The nematic phase is but one of the several mesophases of liquid crystal that possess these interesting nonlinearities. Cholesterics and smectics [4] and other hybrid forms of nematics [6] also possess large nonlinearities. We anticipate that many more effects will be observed in the near future. 

---