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

Applied Physics Letters

Nagai

Furube

et al. 2004

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Ultrafast and large absorption change in the optical telecommunication wavelength region was achieved in solid films by making transitory expansion of a π-electronic system with photoinduced electron transfer and reverse reactions between redox-active ion pairs. Femtosecond dynamics of absorption changes at about 500–1550 nm due to single electron transfer was studied for a poly(tetramethyleneoxide) film containing 2,7-bis(4-pyridiniumyl)fluorene unit as part of the main chain. It showed ON response in less than 100 fs and fastest OFF response in 240 fs at the telecommunication wavelength. This polymer film may be applied to tetrahertz all optical information processing in the telecommunication system.

mentioning

confidence: 99%

Ultrafast optical switching at the telecommunication wavelength by single electron transfer between fluorene-containing redox polymer and its counter anion

Applied Physics Letters

Nagai

Furube

et al. 2004

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“…Very recently we made a preliminary report on synthesis and photoresponses of fluorene-containing redox polymer, which showed new absorption up to 2000 nm by photoinduced electron transfer from tetraphenylborate (TPB À ) anion in addition to extremely fast photoinduced forward and thermal back electron transfer between iodide anion in the NIR region [14]. We also proposed all-optical spatial light modulation and parallel switching based on photoinduced complex refractive index changes in guided mode geometry [15][16][17][18][19][20][21][22][23][24][25][26]. Both transient bleaching and absorption type materials can be used in this system.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast photoresponsive materials and molecular photonics applications by guided wave mode geometry

Science and Technology of Advanced Materials

Nagai

Matsumoto

et al. 2006

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Molecular photonics, information processing based on strong interactions of photons and molecules, has attracted much attention, since it can fully utilize many superior properties of both photons and molecules. We have developed polymeric materials showing ultrafast absorption changes in the visible to near-infrared regions including the telecommunication wavelength by photoinduced electron transfer and reverse reactions between substituted pyridinium and its counter anion. By selecting the counter anion we succeeded in making steady and ultrafast absorption changes. Time-resolved absorption and fluorescence spectroscopy upon femtosecond laser excitation revealed reaction mechanism and ultrafast dynamics. In order to fully utilize such photoresponses in molecular photonics, we proposed guided wave mode (GWM) device composed of a prism, a low refractive index polymer film, and a photoresponsive polymer film. The reflectance in this GWM is controlled by many factors such as thickness values and complex refractive indices of two polymer layers as well as an incident angle and wavelength. We successfully achieved sensitive, all optical, and very fast control of reflectance by means of photoinduced complex refractive index changes upon femtosecond laser excitation. r

“…3 We have also investigated a reflectance type guided wave mode ͑GWM͒ geometry for ultrafast all-optical modulation by the use of two different polymer thin films or a thin polymer film on a metal film. [4][5][6] These GWM films demonstrated much higher modulation sensitivity and wavelength tunability as compared with simple transmittance type device such as FESLAP.…”

mentioning

confidence: 99%

“…1 together with the structure of CuT4, in which we added a polarizer, a quarter-wave plate, and an analyzer to the composite polymer GWM system we reported previously. [4][5][6] Absorption and transient absorption spectra are shown in Fig. 2͑a͒ for an ARTON® ͑JSR, Co. Ltd.͒ film containing CuT4.…”

mentioning

confidence: 99%

Ultrafast all-optical light modulation in the near infrared region by phase sensitive polymer guided wave mode geometry containing porphyrin tapes

Matsumoto

Applied Physics Letters

Aratani

et al. 2009

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A phase sensitive detection was introduced into reflection type all-optical light modulation based on guided wave mode (GWM) geometry. A polymer film containing a copper porphyrin tape and a low refractive polymer film formed GWM at specific incident angle and wavelength. Sensitive changes of output intensity were observed upon femtosecond laser excitation depending on azimuthal angles of the analyzer, which was caused by phase changes at the GWM by Δk alone. The present system has a great advantage as compared with the conventional GWM or simple transmission methods for all-optical light modulation especially for materials showing the ground state absorption.