Study of High-Brightness White Light Point Source Using Ce3+,Sm3+:YAG Crystal Fiber
Date Issued
2010
Date
2010
Author(s)
Cheng, Tzu-Chieh
Abstract
In 2009, the newly inaugurated U.S president Barack Obama has proposed an energy-environment strategic plan focusing on the development of “inexpensive, clean, and highly-efficient energy.” At the same time, the leading countries worldwide are also rising the importance of solid-state lighting research to a national military strategic level, which is aimed at creating an eco-friendly and highly-efficient lighting business. It is estimated that by the 2020, solid-state lighting will be able to save 11% of global energy plus 259 million tons of carbon dioxide emission each year, which is equivalent to saving an expenditure of US$112 billion yearly. Therefore, the field of high-brightness solid-state lighting research has gradually evolved as a mainstream subject of the green-energy industry.
This thesis studies the thin-layers-coating of CeO2 and Sm2O3 on the circumference of pure YAG crystal fiber, and the regrow of coated samples into Ce3+,Sm3+:YAG crystal fibers with 10 μm-diameter core by LHPG method. Referring to present mechanism regarding the color blending of high-brightness white LED, which is formed by combining blue LED with yellow phosphors, this study uses blue laser diode of 446 nm center wavelength as exciting light source, and uses objective lens to focus the laser on crystal-fiber. By the core-excited method, the mechanism can excite Ce3+ and Sm3+ ions and generate yellow broad-band ASE light of 98 nm 3dB bandwidth, which on the one side serve as the light source for high-resolution low Optical Coherence Tomography (OCT) with its axial resolution up to 1.5 μm, and is expected to have great contribution on cell-pathological-changes detection as well as LCD’s pretilt angle measurement; and on the other side will blend with residuary blue light and turn into white light with its brightness close to Ultra-high-Pressure (UHP) mercury lamp at highest brightness level of 100M~1G cd/m2 and chromaticity coordinates of (0.3022,0.3335) nearly at the center of the chromaticity diagram. In addition, according to the measurement results of small-signal gain experiment, Ce3+,Sm3+:YAG crystal fiber can create 5.47 dB gain of -29.33 dBm signal at 100 mW exciting power. For future research perspective, by using AR coating for exciting light source and HR coating at wavelength near 532 nm, it is possible to form laser resonator, which can achieve the development of Ce:YAG crystal fiber laser, or the development of green-band optical amplifier.
Subjects
high brightness
white light
YAG
crystal fiber
Ce
Sm
File(s)![Thumbnail Image]()
Loading...
Name
ntu-99-R96941005-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):611b41403ceefa63bce433f991fa69a9