Spiropyrans and Spirooxazines for Memories and Switches

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Active plasmonics is a burgeoning and challenging subfield of plasmonics. It exploits the active control of surface plasmon resonance. In this review, a first-ever in-depth description of the theoretical relationship between surface plasmon resonance and its affecting factors, which forms the basis for active plasmon control, will be presented. Three categories of active plasmonic structures, consisting of plasmonic structures in tunable dielectric surroundings, plasmonic structures with tunable gap distances, and self-tunable plasmonic structures, will be proposed in terms of the modulation mechanism. The recent advances and current challenges for these three categories of active plasmonic structures will be discussed in detail. The flourishing development of active plasmonic structures opens access to new application fields. A significant part of this review will be devoted to the applications of active plasmonic structures in plasmonic sensing, tunable surface-enhanced Raman scattering, active plasmoni...

Active Plasmonics: Principles, Structures, and Applications

Hybrid Resonant Organic Inorganic Nanostructures for Optoelectronic Applications V. M. Agranovich,* Yu. N. Gartstein, and M. Litinskaya NanoTech Institute, Chemistry Department, The University of Texas at Dallas, Richardson, Texas 75083, United States Institute of Spectroscopy, Russian Academy of Science, Troitsk, Moscow Region 142190, Russia Department of Physics, The University of Texas at Dallas, P.O. Box 830688, EC36, Richardson, Texas 75083, United States Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada

Hybrid resonant organic-inorganic nanostructures for optoelectronic applications.

The review describes the photochromic and fluorescent characteristics of various diarylethene (DAET) derivatives, and presents recent research into their applications. This comprises a discussion of the optical characteristics of some DAET-based molecules exhibiting red, green, or blue (RGB) colors or fluorescence. Molecular calculations of the optical properties of DAET interpret intriguing experimental observations and predict photochemical or photophysical properties. In particular, stabilization of HOMO in the BTFO n ( n  = 1, 2, 3, 4) increases the energy difference between the HOMO and the LUMO, which leads to the blue-shift of absorption and emission bands as the number of oxygen attached to sulfur ( n ) increases. Various devices and application studies have been designed as photon-mode systems based on photochemical control of the fluorescence energy. The photochromic DAET materials have shown promise as optical data storage, switching devices, and biological applications such as the development of biomaterial sensors, analysis of biological dynamics, and live cell imaging.

Photochromic fluorescence switching from diarylethenes and its applications

An all-optical ultrafast switch which operates at a wide wavelength range has been demonstrated based on photoinduced changes of real and/or imaginary parts of complex refractive index in a composite thin film of silver and polymer containing photochromic spiropyran dye. Very fast switching ON and OFF of a reading beam within 20 ns in a 400–800 nm range was achieved at the incident angle of guided-wave mode using a photochromic spiropyran-doped polystyrene thin film and a ns pulsed UV or visible laser as a writing beam. These responses were caused by the changes of complex refractive index due to photochromism. No applied power was required to hold the switched state. An image was also written to the probe beam by irradiation through a pattern.

Ultrafast wide range all-optical switch using complex refractive-index changes in a composite film of silver and polymer containing photochromic dye

An all-optical switch has been proposed based on photoinduced changes of an imaginary part of complex refractive index in a composite thin film made by silver and polymer thin films containing photochromic dye. Very fast switching on and switching off of a reading beam was demonstrated at the incident angle of guided wave mode using a photochromic spiropyran-doped polystyrene thin film and a ns pulsed laser as a writing beam. These responses were caused by the changes of an extinction coefficient due to photochromism. No applied power was required to hold the switched state.

Ultrafast all-optical switch using complex refractive index changes of thin films containing photochromic dye

Ultrafast all-optical spatial light modulation based on complex refractive index changes of copper phthalocyanine-doped polymer film upon photoexcitation in guided mode geometry

A novel all-optical parallel switching device was demonstrated by using photoinduced changes of a complex refractive index in a guided mode thin film composed of silver and polymer containing photochromic dyes An incident angle of a probe beam was set at a value corresponding to the minimum reflection due to the guided mode Pulsed laser excitation caused changes of absorption of the polymer films due to photochromism, which resulted in the increase of reflection because the guided mode condition was changed According to the Kramers-Kronig relationship the real part also changes, which results in the shift of the minimum Appropriate wavelength can be selected for all-optical switching in this geometry We used photochromic spiropyran dispersed in polystyrene Self-held parallel switching was achieved upon UV or visible laser excitation with response times less than 20 ns

Kyoichi Sasaki

Papers

Ultrafast wide range all-optical switch using complex refractive-index changes in a composite film of silver and polymer containing photochromic dye

Ultrafast all-optical switch using complex refractive index changes of thin films containing photochromic dye

Ultrafast all-optical spatial light modulation based on complex refractive index changes of copper phthalocyanine-doped polymer film upon photoexcitation in guided mode geometry

Reflection-Mode All-Optical Parallel Switching in Guided Wave Geometry Including Photochromic Compounds

Optical waveguide studies on photoinduced electrochromism in ultrathin films of ion-pair charge-transfer complexes of 4,4′-bipyridinium ions