scholarly journals Azo-dye-doped absorbing photonic crystals with purely imaginary refractive index contrast and all-optically switchable diffraction properties

2011 ◽  
Vol 2 (1) ◽  
pp. 55 ◽  
Author(s):  
Y. J. Liu ◽  
H. T. Dai ◽  
Eunice S. P. Leong ◽  
J. H. Teng ◽  
X. W. Sun
Keyword(s):  
Refractive Index ◽  
Photonic Crystals ◽  
Azo Dye ◽  
Refractive Index Contrast ◽  
Index Contrast

Coupling Properties of Defect Modes in Organic Octagonal Quasiperiodic-Photonic-Crystals Under Low-Refractive-Index Contrast

2018 ◽  
Vol 38 (2) ◽  
pp. 0216003
Author(s):  
蔡园园 Cai Yuanyuan ◽  
王智 Wang Zhi ◽  
陈笑 Chen Xiao ◽  
李长伟 Li Changwei ◽  
冯帅 Feng Shuai ◽  
...  
Keyword(s):  
Refractive Index ◽  
Photonic Crystals ◽  
Defect Modes ◽  
Refractive Index Contrast ◽  
Index Contrast ◽  
Low Refractive Index

Room temperature 1.3–1.55 μm laser-like emission from Ge/Si self-assembled islands in Si-based photonic crystals

2003 ◽  
Vol 797 ◽  
Author(s):  
J-M. Lourtioz ◽  
S. David ◽  
M. El Kurdi ◽  
C. Kammerer ◽  
X. Li ◽  
...  
Keyword(s):  
Refractive Index ◽  
Photonic Crystals ◽  
Inductively Coupled Plasma ◽  
Room Temperature ◽  
Coupling Efficiency ◽  
Silicon On Insulator ◽  
Main Body ◽  
Refractive Index Contrast ◽  
Index Contrast ◽  
Self Assembled

ABSTRACTExperimental results are reported on various guided optic configurations that combine silicon-based photonic crystals (PC) and Ge/Si quantum island emitters. The feasibility of low-refractive-index-contrast PC waveguides by inductively-coupled-plasma (ICP) etching of buried SiGe/Si waveguides is briefly recalled from a previous work. The main body of the paper is focused on experiments that were carried out on the high-refractive-index-contrast silicon-on-insulator (SOI) system. Self-assembled Ge/Si quantum island layers were deposited on a SOI substrate that was further processed to get two-dimensional PC microcavities and waveguides. The room temperature 1.3–1.55 μm emission from Ge/Si islands is shown to be significantly enhanced in PC microcavities, the strongest enhancement being obtained with the smallest (micropillar-like) cavities surrounded by wide pores. In this latter case, the room-temperature photoluminescence amplitude is more than two-orders of magnitude larger than that of Ge/Si islands grown in unprocessed samples. A superlinear (laser-like) dependence with the optical pumping is observed in the same time. This behavior and other experimental trends would incriminate both a high carrier concentration of the photo-created electron-hole plasma and a good vertical coupling efficiency of the micro-structured silicon. A first attempt to characterize linear PC waveguides is also reported using the wideband luminescence of Ge/Si islands embedded in the guides.

scholarly journals Optical Sensitivity of Waveguides Inscribed in Nanoporous Silicate Framework

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 123
Author(s):  
Zhong Lijing ◽  
Roman A. Zakoldaev ◽  
Maksim M. Sergeev ◽  
Andrey B. Petrov ◽  
Vadim P. Veiko ◽  
...  
Keyword(s):  
Refractive Index ◽  
Near Field ◽  
Experimental Studies ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Direct Writing ◽  
Sensor Applications ◽  
Refractive Index Contrast ◽  
Optical Sensitivity ◽  
Index Contrast

Laser direct writing technique in glass is a powerful tool for various waveguides’ fabrication that highly develop the element base for designing photonic devices. We apply this technique to fabricate waveguides in porous glass (PG). Nanoporous optical materials for the inscription can elevate the sensing ability of such waveguides to higher standards. The waveguides were fabricated by a single-scan approach with femtosecond laser pulses in the densification mode, which resulted in the formation of a core and cladding. Experimental studies revealed three types of waveguides and quantified the refractive index contrast (up to Δn = 1.2·10−2) accompanied with ~1.2 dB/cm insertion losses. The waveguides demonstrated the sensitivity to small objects captured by the nanoporous framework. We noticed that the deposited ethanol molecules (3 µL) on the PG surface influence the waveguide optical properties indicating the penetration of the molecule to its cladding. Continuous monitoring of the output near field intensity distribution allowed us to determine the response time (6 s) of the waveguide buried at 400 µm below the glass surface. We found that the minimum distinguishable change of the refractive index contrast is 2 × 10−4. The results obtained pave the way to consider the waveguides inscribed into PG as primary transducers for sensor applications.

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