2008.6
About Instruments Today No. 164
Applications of Laser Processing
Fabrication of CdSe Micro/Nano Structures by Two Photon Absorption Induced Polymerization Technique Cooperated with Electrochemical Deposition Technique [ 下載 PDF ]
Sean Liu, Tsung-Hsien Tsai, Po-Wen Chen, Jian-Hung Lin, Ngoc Diep Lai, Cheng-Yi Wu, Chia-Chen Hsu
In this report, a home-made Ti:sapphire femto-second laser was used as a light source to carry out two-photon (or multi-photon) polymerization on negative-tone SU8 and positive-tone AZ4620 photoresists. Using this technique we successfully fabricated one-, two-, and three-dimensionally periodic structures. Arbitrary types of defects can be introduced in these structures by arranging the exposed positions which were controlled by computer programs. To increase the index of refraction of photonic crystals, we used electric-deposition technique to deposit two-dimensional CdSe structures of a high refractive index on photoresist patterned substrates. Photoresists were then removed to increase the refractive index contrast to broaden the photonic bandgaps of photonic crystals.
Micro-Machining by Ultrafast Laser and Its Future Development [ 下載 PDF ]
Hong-Tsu Young, Fang-Fei Lin, Shin-Yi Huang
The material removal mechanism by laser micro-machining have two basic forms: pyrolysis and photolysis. The processing via photolysis removes materials in a way that photons break the interatomic bonds of the material directly, and the corresponding machining accuracy will be much higher than that via pyrolysis. The femtosecond laser has a characteristic of extremely short pulse, whose working mechanism falls in photolysis category. The research on femtosecond laser applications has not been widely carried out at present in Taiwan. This research was planned on the fundamental investigation and a comparison was made with the Nd:YVO4 laser which has been widely applied in industry.
Femtosecond Laser and Its Applications in Micromachining [ 下載 PDF ]
Chung-Wei Cheng
To overcome the large heat-affected zone and low accuracy caused by conventional long pulse duration lasers, the worldwide research institutes have paid attention to develop the femtosecond laser machining technologies. However, the current performance of femtosecond laser machining is limited by the low throughput, and the highaccuracy and high-speed femtosecond laser machining technologies are being developed in order to overcome these disadvantages. This paper describes the mechanisms of femtosecond laser micromachining. Also, the advanced applications of femtosecond laser micromachining in internal transparent, metal and thin film transparent conductor materials are introduced.
Laser Application for Glass Thermal Fracture Cutting Technology [ 下載 PDF ]
Wen-Hong Wu
The laser thermal fracture cutting technology for brittle materials has become the main technology for LCD glass substrate cutting. This laser thermal fracture cutting technology can be applied to the thick plate glass cutting manufacture process for furniture industry as well. The thermal fracture cutting theory and applications of laser in thermal fracture cutting have been told in this article. And brief introductions of the development of laser thermal fracture cutting technology in ITRC were shown in this article.
Laser Patterning Technology in Flexible Display [ 下載 PDF ]
Hsuan-Kai Lin, Sung-Ho Liu, Da-Long Cheng
Laser patterning technology has been widely used to manufacture the electrode of display. Because flexible display is a trend, substrate material will play a key role to affect ablated quality of the electrode. After patterning these ITO/glass and ITO/PET materials, the edge of the ablated sections was observed the melt ridge build-up on both samples. This study investigated the edge of the ablated sections was relative to fluence and overlap of laser in order to obtain optimal ablated quality of the electrode.
Simulation and Analysis of Cutting Metallic Materials by High Power CO2-Laser [ 下載 PDF ]
Shih-Feng Tseng, Kuo-Cheng Huang, Ming-Fei Chen, Wen-Tse Hsiao
This investigation has considered laser output powers, absorption by material surface, the specific energy of materials, the radius of the focused laser beam and density of materials to simulate the material relation with maximum cutting speed versus cutting depth. By experiment of laser cutting, we find out the modified factor and compensate another neglecting of parameters. Then, we predict the cutting metallic characteristic for high power CO2 laser. Although the simulated values do not match the experimental values, the tendency is in agreement. Substituting for experimental values into the modified equation, the precise estimation of the relation with maximum cutting speed versus cutting depth can be obtained.
2007 Analyses of Worldwide Laser Market [ 下載 PDF ]
Wei-Chieh Zhuang
The application of laser is getting more and more popular in the field of the manufacture, electronic products, entertainment, instrument, military and so on. The material processing, optical storage, communication, and medical are approximately composes 90 percent of the entire laser use. In the future the electronic products development will face the short and the multi-purpose, so the laser processing technique will play a key factor. Therefore this article will analyze the overall laser industry production, Bmarketing situation, Bmaterial processing, Boptical storage, and medical field in 2007.
Introduction of Progress in NMR Techniques for Large Biomolecules [ 下載 PDF ]
Shing-Jong Huang, Ying-Chih Lin
Nuclear magnetic resonance (NMR) spectroscopy, extensively and successfully employed in many fields, has become one of the most important tools for studying biological macromolecules with the remarkable progress in both experimental techniques and hardware improvement in the past decades. This article briefly introduces recent significant progress in experimental techniques capable of improving sensitivity and resolution of spectra for very large biomolecules (> 50 kDa) and refinement of protein structures. In addition, conventional experiments of multidimensional NMR are very time-consuming to achieve well-resolved spectra. Recent advance of experiment techniques for shortening days-long acquisition time is also mentioned.
MEMS-Based Components and Modules for Optical Communication [ 下載 PDF ]
Jui-che Tsai
With the continuous growth of optical fiber communication, the development of related components and modules has been progressing. Variable optical attenuators (VOA), dynamic spectral equalizers (DSE), and wavelength-tunable devices (such as lasers and filters) are among those which are of great interest. The idea of using MEMS technologies to implement these devices has led to many hot research topics in both academia and industry. In this article, we not only provide a comprehensive introduction of the MEMS applications to optical fiber communication, but also bring to the readers’ attention another field of growing interest, free-space optical communication.
A Simple Process in Single Biomolecule Analysis by Total Internal Reflection Fluorescence Microscopy [ 下載 PDF ]
Su-Ming Hu
Total internal reflection fluorescence microscopy (TIRFM) can produce an image and spectrum at a nanometer resolution and with a high signal/noise ratio. This technique is applied to single biomolecule analysis in a growing trend. This text will introduce the basic principle of TIRFM and the techniques combined to TIRFM. In addition, the interaction of protein-nucleic acid will demonstrate the application of TIRFM to single-molecule assay in biological research.
Potential of Using High-Resolution Canopy Reflectance Spectrum to Assess Disease Severity of Rice Bacterial Leaf Blight [ 下載 PDF ]
Chwen-Ming Yang
The bacterial leaf blight (BLB) is an important vascular disease to irrigated rice and may cause substantial yield loss under serious conditions. This study analyzed near-ground canopy hyperspectral reflectance of two rice cultivars (Oryza sativa L.), TNG 67 and TCS 10, infested with various levels of the pathogen so as to establish spectral models for assessing disease severity for future applications in site-specific management. Cultivar TCS 10 is an indica type of high susceptibility and cultivar TNG 67 is a japonica type with moderate susceptibility. Field experiment was conducted to produce various levels of BLB infestations for canopy reflectance measurements and spectral characteristics (SCs) associated with disease symptoms were identified for models establishment. Results suggest that the approaches used for hyperspectral analysis in this study are less complex and are conceptually easy to understand. Correlation of disease symptoms and SCs is high in BLB-infested plants so that disease severity may be properly assessed.
