ALL-OPTICAL REFLECTANCE CONTROL BASED ON PHOTOINDUCED COMPLEX REFRACTIVE INDEX CHANGES IN GUIDED MODE THIN FILMS CONTAINING INDIUM OR GALLIUM PHTHALOCYANINES

2002 ◽  
Vol 11 (03) ◽  
pp. 205-218 ◽  
Author(s):  
TOSHIHIKO NAGAMURA ◽  
ATSUSHI NAITO ◽  
IORI YOSHIDA ◽  
YU CHEN ◽  
MICHAEL HANACK
Keyword(s):  
Thin Film ◽  
Refractive Index ◽  
Complex Refractive Index ◽  
Nanosecond Laser ◽  
Polymer Thin Film ◽  
Optical Reflectance ◽  
Guided Mode ◽  
All Optical ◽  
Silver Thin Film ◽  
Index Changes

Tetrasubstituted indium or gallium phthalocyanines and their dimers bridged with various ligands were dispersed in a polymer thin film, which was spin-coated on silver thin film vacuum-evaporated on a glass slide. All-optical reflectance control was achieved by complex refractive index changes upon photoexcitation of phthalocyanines by nanosecond laser in such a guided mode geometry. They gave rise in less than ns pulse width, and a few to a few tens of microseconds decay characteristic to the lifetime of the excited triplet state. Repeated and reversible reflectance changes were achieved. Axially bridged phthalocyanine dimers showed almost the same photoresponses as monomers.

Dispersion Properties of Photonic Crystal Fibers - Issues and Opportunities

2003 ◽  
Vol 797 ◽  
Author(s):  
J. Lægsgaard ◽  
S. E. Barkou Libori ◽  
K. Hougaard ◽  
J. Riishede ◽  
T. T. Larsen ◽  
...  
Keyword(s):  
Refractive Index ◽  
Photonic Crystal ◽  
Optical Fibers ◽  
Photonic Crystal Fibers ◽  
Complex Refractive Index ◽  
Dispersion Properties ◽  
Guided Mode ◽  
Index Contrast ◽  
Mode Group ◽  
Crystal Fibers

ABSTRACTThe dispersion, which expresses the variation with wavelength of the guided-mode group velocity, is one of the most important properties of optical fibers. Photonic crystal fibers (PCFs) offer much larger flexibility than conventional fibers with respect to tailoring of the dispersion curve. This is partly due to the large refractive-index contrast available in silica/air microstructures, and partly due to the possibility of making complex refractive-index structures over the fiber cross section. We discuss the fundamental physical mechanisms determining the dispersion properties of PCFs guiding by either total internal reflection or photonic bandgap effects, and use these insights to outline design principles and generic behaviours of various types of PCFs. A number of examples from recent modeling and experimental work serve to illustrate our general conclusions.

Determination of thin film refractive index and thickness by means of film phase thickness

Open Physics ◽  
2008 ◽  
Vol 6 (2) ◽  
Author(s):  
Milen Nenkov ◽  
Tamara Pencheva
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Refractive Index ◽  
Barium Titanate ◽  
Spectral Region ◽  
Complex Refractive Index ◽  
Refractive Index Dispersion ◽  
New Approach ◽  
Phase Thickness

AbstractA new approach for determination of refractive index dispersion n(λ) (the real part of the complex refractive index) and thickness d of thin films of negligible absorption and weak dispersion is proposed. The calculation procedure is based on determination of the phase thickness of the film in the spectral region of measured transmittance data. All points of measured spectra are included in the calculations. Barium titanate thin films are investigated in the spectral region 0.38–0.78 μm and their n(λ) and d are calculated. The approach is validated using Swanepoel’s method and it is found to be applicable for relatively thin films when measured transmittance spectra have one minimum and one maximum only.

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