scholarly journals Enhancement of the evanescent wave coupling effect in a sub-wavelength-sized GaAs/AlGaAs ridge structure by low-refractive-index surface layers

2014 ◽  
Vol 22 (S6) ◽  
pp. A1559 ◽  
Author(s):  
Xue-Lun Wang ◽  
Guo-Dong Hao ◽  
Tokio Takahashi
Keyword(s):  
Refractive Index ◽  
Evanescent Wave ◽  
Coupling Effect ◽  
Surface Layers ◽  
Wave Coupling ◽  
Ridge Structure ◽  
Sub Wavelength ◽  
Low Refractive Index

Enhanced light extraction in GaN-based light-emitting diodes by evanescent wave coupling effect

2014 ◽  
Vol 7 (10) ◽  
pp. 102101 ◽  
Author(s):  
Guo-Dong Hao ◽  
Ahmed Mohammed Jahir ◽  
Tokio Takahashi ◽  
Mitsuaki Shimizu ◽  
Xue-Lun Wang ◽  
...  
Keyword(s):  
Evanescent Wave ◽  
Light Emitting Diodes ◽  
Coupling Effect ◽  
Light Extraction ◽  
Wave Coupling ◽  
Light Emitting

scholarly journals Hollow Fiber Coupler Sensor

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 806 ◽  
Author(s):  
Nithin Kuruba ◽  
Tao Lu
Keyword(s):  
Refractive Index ◽  
Hollow Fiber ◽  
Evanescent Wave ◽  
Directional Coupler ◽  
Experimental Results ◽  
Refractive Indices ◽  
Coupling Mechanism ◽  
Hollow Core ◽  
Wave Coupling ◽  
Fiber Coupler

We present a bi-conical optical directional coupler composed of solid and hollow core fibers. Through an evanescent wave coupling mechanism, the detection of liquid refractive index and its temperature are demonstrated. The experimental results illustrated that the sensor offers a sensitivity of 4.03 ± 0.50 volts per refractive index units (V/RIU) for refractive indices ranging from 1.331 ± 0.003 to 1.403 ± 0.003 with a resolution of 3.5 × 10 − 3 refractive index units (RIU).

Photochemical Deposition of Transparent Low Refractive Index SiO2 Topcoat for Laser Head at Room Temperature

2004 ◽  
Vol 843 ◽  
Author(s):  
Y. Tezuka ◽  
M. Murahara
Keyword(s):  
Refractive Index ◽  
Evanescent Wave ◽  
Room Temperature ◽  
Visible Region ◽  
Antireflection Coating ◽  
Mixed Gas ◽  
Laser Head ◽  
Photochemical Deposition ◽  
Glass Slab ◽  
Low Refractive Index

ABSTRACTA transparent, low refractive index SiO 2 film was photo-chemically laminated on a glass slab laser head by the Xe2* excimer lamp in the atmosphere of NF3 and O2 mixed gas at room temperature; which made it possible to inhibit the decrease in the laser output power caused by the evanescent wave leakage.The transparent SiO2 film of 260nm thickness was laminated on the non-heated substrate by the lamp irradiation for one hour. The hardness of the film before annealing was 3 by Mohs’ Scale of Hardness, and its hardness improved to 5 after annealing at 250 degrees centigrade for one hour. The refractive index of the film was 1.42, being lower than the index of silica glass that is 1.46. Furthermore, the transmittance in the visible region increased by 2% with it s antireflection coating.

Anti–scatter coating on slab laser head for preventing evanescent wave by photo–oxidation of silicone oil

2005 ◽  
Vol 890 ◽  
Author(s):  
Takayuki Funatsu ◽  
Nobuhiro Sato ◽  
Yuji Sato ◽  
Takayuki Okamoto ◽  
Masataka Murahara
Keyword(s):  
Thin Film ◽  
Refractive Index ◽  
Evanescent Wave ◽  
Room Temperature ◽  
Silicone Oil ◽  
Total Reflection ◽  
Excimer Lamp ◽  
Laser Head ◽  
Slab Laser ◽  
Low Refractive Index

ABSTRACTA low refractive index, hard SiO2 film was photochemically coated on the surface of slab laser head at room temperature by using silicone oil and a Xe2 excimer lamp. Nd+:glass slab laser produces high power laser because the light is amplified with a repeated total reflection in the laser medium. However, an evanescent wave arises on the total reflection interface, which causes a loss of the light energy. A low refractive index film 2 μm thick is, therefore, needed to prevent this problem. The vacuum vapor deposition method as a dry process and the spin-coating method as a wet process are generally used for making optical thin films. The former method can laminate a hard thin film, but requires temperatures above 500°C, and the thermal denaturation of the optical substrate is unavoidable. On the other hand, the latter method can form a low refractive index thin film, but the produced thin film has a poor adhesiveness and a low hardness. Besides, all these films are inferior in water resistance. We, therefore, formed a water-resistant, hard, and low refractive index protective coating directly on the laser glass surface at room temperature with photochemical reaction by the Xe2 excimer lamp.

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