2004 Fiscal Year Final Research Report Summary
Directional Couplers using Organic Nonlinear Material Bacteriorhodopsin
| Project/Area Number |
14550004
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Applied materials science/Crystal engineering
|
|---|
| Research Institution | The University of Electro-Communications |
|---|
Principal Investigator |
OKADA Yoshiko The University of Electro-Communications, Faculty of Electro-Communications, Assistant Professor, 電気通信学部, 助手 (50231212)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
ISHIHARA Teruya RIKEN(The Institute of Physics and Chemical Research), Frontier research system, Team Leader, フロンティア研究機構励起子工学研究チーム, チームリーダー (60168250)
|
|---|
| Project Period (FY) |
2002 – 2004
|
| Keywords | bacteriorhodopsin / potonic crystal slab / waveguide mode / potoinduced transmission change / optical switching / 方向性結合器 |
|---|
| Research Abstract |
We have studied photonic crystal slab coated with bR-PVA layer for light-controlled optical switching. The photonic crystal slab was fabricated on a quartz substrate by means of the electron-beam lithography and reactive ion etching technique. We fabricated ten gratings with grating pitch L are from 600 to 720 nm. The transmitted intensity of light through the sample was measured at room temperature, as a function of the photon energy. In a thin waveguide, only the zero order TE and TM light mode can propagate. One of the typical results of the coupling to the waveguide modes is the appearance of sharp dips in the transmission spectrum. We altered the incident angle from-40 to 40 degrees. The polarization of the incident light is parallel to the grating line. We have observed the sharp transmission dips excited by waveguide modes and the photoinduced transmission change caused by refractive index change of bR. Quality (Q) factor of this resonator is estimated to be about 10^3 from the typical dip width (FWHM) 0.95 nm.
Since the waveguide modes have a significant evanescent component, coupling to or from an external wave is strongly influenced by the refractive index of the material above the grating area. Thus, a change of refractive index of bR modulate the transmission spectra. In our measurements, the maximum shift of transmission dip was approximately 2.0 nm. These results demonstrate the feasibility of using a protein as a programmable active material in integrated optical devices. We have proposed that the shift of dips can be applied for light controlled optical switching. Hence, the fabrication of nanoscale structured optical device such as photonic crystal slab coated with bR polymer is a primary technological task. Not only chemical but also genetic control of optical properties of bR offers a great possibility for design of integrated optical device.
|
