Hani J. Kbashi
材料科学技术（英文）
The thin, long length and high smoothness silica photonic nanowires and taper optical fiber were fabricated using a simple and low cost chemical etching method. A two-steps wet etch process were used consisting of etching with 30% HF acid to remove cladding and 24% HF acid to decrease fiber core diameter. An approach for on-line monitoring of etching using 1300 nm light power transmitted in the optical fiber was used to determine the diameter of the remaining core and showed a transition between two different operation regimes of nanofiber from the embedded regime, where the mode was isolated from the environment, to the evanescent regime. The data indicated that the diameter of the silica fiber decreased linearly for both 30% and 24% HF acid with 1.2 and 0.1 μm/min grad diameter, respectively at room temperature, and more than 70% of the mode intensity could propagate outside fiber when the core diameter was less than 1 μm. The results of fiber taper showed that the fiber was tapered by a factor of 20 while retaining a thin core structure
and leaving about more than 85% of core structure.
关键词:
Chemical etching
Taohua HUANG
,
Shengming ZHOU
,
Hao TENG
,
Hui LIN
,
Jun ZOU
,
Jianhua ZHOU
,
Jun WANG
材料科学技术（英文）
γ-LiAlO2 single crystal is a promising substrate for GaN heteroepitaxy. In this paper, we present the growth of large-sized LiAlO2 crystal by modified Czochralski method. The crystal quality was characterized by highresolution X-ray diffraction and chemical etching. The results show that the as-grown crystal has perfect quality with the full width at half maximum (FWHM) of 17.7–22.6 arcsec and etch pits density of (0.3–2.2)×104 cm-2 throughout the crystal boule. The bottom of the crystal boule shows the best quality. The optical transmission spectra from UV to IR exhibits that the crystal is transparent from 0.2 to 5.5 μm and becomes completely absorbing around 6.7 μm wavelength. The optical absorption edge in near UV region is about 191 nm.
关键词:
γ-LiAlO2 crystal
,
提拉法
,
化学腐蚀
,
透过光谱
