2005.8
About Instruments Today No. 147
Terahertz Technology
Tunable Terahertz-Radiation by Difference Frequency Generation in GaSe Crystal [ 下載 PDF ]
Yu-Kuei Hsu, Ching-Wei Chen, Chen-Shiung Chang, Ci-Ling Pan
Recent developments in nonlinear optical materials and laser technology have led to the development of terahertz radiation sources based on nonlinear optical technique. Based on phasematched collinear different-frequency generation in a single GaSe crystal, coherent terahertz radiation sources can be efficiently generated and tuned in extremely wide ranges. This is due to the fact that GaSe has the lowest absorption coefficient and large nonlinear optical coefficient. Moreover, the characteristics and applications of coherent terahertz radiation sources will be introduced in this paper.
"Design, Fabrication and Analysis of Two-Dimensional Terahertz Photonic Crystals" [ 下載 PDF ]
Sheng-fu Horng, Cheng-Chung Chi, Ruey-Shing Star Huang
Two dimensional (2D) terahertz (THz) photonic crystals were fabricated by stacking micromachined high-resistance silicon substrates. The transmission spectra through 1 to 8 stacked silicon substrates with polarization parallel and perpendicular to the grooves were measured. At normal incidence with either polarization the normalized transmission spectrum quickly converges as the number of stacked substrates increases. For as few as three stacked Si substrates, the observed transmission spectra for the first two bands converge reasonably well to the calculated results for an infinite lattice. Agreement between measurements and calculations is obtained at frequencies lower than 0.4 THz and can be further improved with matrix elements calculated from actual geometry. Oblique incidence is also measured and analyzed.
THz Emitter and Detector Based on Semiconductor [ 下載 PDF ]
Hung Hsiang Cheng
In this report, semiconductor terahertz (THz) emitters and detectors are introduced. The background and present status in the area are briefly described, followed by a practical example for application. The operation principle of both emitter and detector based on III-V and IV-IV semiconductor compound is discussed. Both emission spectrum and detector's spectral response are demonstrated.
THz Receiver System with Quantum Noise Limit Sensitivity [ 下載 PDF ]
Ming-Jye Wang
The development of SIS (superconductor-insulator-superconductor) mixer provides a significant tool to astronomer for understanding the universe through THz window. AISAA (Institute of Astronomy and Astrophysics, Academia Sinica) participated the SMA (Sub-millimeter Array) project since 1996 and have developed THz receiver system with quantum noise limit sensitivity. These receiver systems have been installed in SMA and perform as part of array. This article will introduce the design and fabrication of SIS mixer and receiver system performance on THz frequency band.
A Novel Micro Optical System for Monolithic Integration of Optical Disk Pickup Heads [ 下載 PDF ]
Heng-Cang Hu, Fan-Gang Tseng
As the progress of IT, the need for high speed and high-density data storage has become increasingly important. Denser and faster data storage methods have also been under developing for next generation need. As a result, the performance of optical storage units, such as an optical pickup head, need to be further improved to accommodate this new desire. However, commercial optical disk pickup head is mostly constructed with bulk micro-optics and many discrete components. The assembly needs intensive labors and poses large-size heads, greatly limiting operation speed and alignment accuracy. This study proposes a novel method to integrate precisely fabricated inclinedmirrors and on-chip Fresnel lens for optical pickup-head application. A new technology of glycerolcompensated incline-exposure has been adopted for the fabrication of 45° mirror pairs. This new integration approach provides an easy and low cost fabrication mean without the need of assembly. Furthermore, this study also proposes a novel method to fabricate the micro SU-8 lens. The novel SU-8 micro lens can be integrated with the micro optical pick-up head as a micro objective lens.
Optimal Design for the Cantilever Main Structure of an Optic System Using Taguchi Method [ 下載 PDF ]
Jui-Pin Chen, Ruei-Hung Tsai, Ting-Ming Huang
This article discusses the influences of the design parameters for the cantilever main structure of optic systems. The object is to find out the optimal design to control the decenter and tilt of the main structure after gluing. Taguchi method is used to analyze the influence of each parameter, and optimum parameters have been obtained. To minimize the required budget, half size of structure has been adopted in the experiments while keeping the other parameters, e.g. materials and the assembly processes, the same in order to extend the results to the original case.
Developing of the Circuit of High-Resolution Linear CCD Module [ 下載 PDF ]
Ji-Jer Huang, Meng-Hsiu Wu, Chun-Fu Lin, Che-Cheng Huang
The detecting device is similar to the human vision nerve. The image light energy collected is changed into the electric energy that convenient people dealt with. At same time, the signal will be digitalized to further information processing. The light detecting device most often used for people at present are the both devices, one is charge coupled device (CCD); the other is complementary metal oxide semiconductor (CMOS). We will introduce their principles and it's excellence and drawback a little. Because CCD detecting device has many advantages that are better sensitivity, higher value of SNR and good stability, the high resolution linear CCD is used in this research. And module idea is applied to design. The preliminarily CCD module had been finished via our circuit design, manufacture, assemble with except fault, and writing firmware and software. By the experiment of preliminary photoelectric parameters, we obtained these parameters including better linearity which is better than 0.998 and good PRNU is less than 10% about our designed module. At the same time, the lens were mounted and focused at the focus plane of CCD device. After, we did experiment of capture image outdoor and obtained the real outdoor image, succeeded in verifying the feasibility with this CCD module system, also offer us to improve the problems in the future.
Drosophila Learning and Memory Testing Machine [ 下載 PDF ]
Tsung-Pin Pai, Ann-Shyn Chiang
For thousands of years, we humans are always highly curious about how our brains work. After the completion of human genomics project, scientists have now shifted their attention to 'deconstruct' neural networks in the brain. Using the sophisticated genetic tool boxes developed in Drosophila studies, scientists have identified a full range of genes involved in its learning and memory. These memory genes have been proven to be evolutionarily conservative and play a similar role in human memory. Here, we introduce (1) the molecular mechanisms in Drosophila olfactory-associated learning, (2) how to screen for genes involved in Drosophila learning and memory, (3) and the recent development in the Drosophila learning machine.
"Isothermal Titration Calorimetry: Measurements of Conformational Change, Kinetics and Binding Constant for Proteins at Nanocalory Scale" [ 下載 PDF ]
Yu-Ming Wang, Ji-Liang Chen, Long-Sun Huang, Chih-Yuan Lee, Chih-Kung Lee, Shiming Lin
There are many methods to analyze the biomolecular interactions, such as ELISA, RIA, SPR and DPI etc. However, the disadvantages of these methods have to fix the samples on substrate or to label in indirect analysis in non-physiological solution. Isothermal titration calorimetry can detect these small changes in heat at this process of biomolecular interactions to measure the change in enthalpy directly. ITC systems permit to complete the molecular interactions with as little as a few nanomoles of material and take only 30–60 min to complete and are highly automated, including instrument operation and data collection and analysis. It is also to get enzyme kinetic parameters and the changes of enthalpy on protein folding.
The Detection of Hospital Indoor Air Quality [ 下載 PDF ]
Fu-Der Mai, Chia-Fang Tsai, Yu-Wen Hsu, Wen-Kang Chen
People in the industrialized world spend about 90% of their life's indoors, and there is an increasing concern about possible health effects of the indoor environment. Indoor environment may influence the occurrence of symptoms such as eyes, skin, and upper airway irritation, headache and fatigue. However, most of the studies on subjective indoor air quality, symptoms, and clinical signs form eyes or upper airways have been performed on office workers or school personnel, and there are few indoor air studies in hospital environment. The aim of this paper is to study relations between subjective indoor air quality, in particular the effect of dampness, type of building, concentration of CO2, CO, O2 and total hydrocarbon (THC), and air humidity.
Study in Carbon Monoxide Sensor by Application of CoOOH Material [ 下載 PDF ]
Ren-Jang Wu, Tung-kang Tsai, Yih-Lu Sun, Chuin-tih Yeh
Different oxidation type of CoOx were prepared from the precursor of Co(NO3)2 solution through a precipitation with NaOH and oxidation by air. Furthermore, the prepared samples were applied for sensing materials of semiconductor type CO sensors. In this study, the optimum working temperature of CO detection was about 80 °C (S = 5.6). At low temperature, CoOOH exhibits better sensitivity than Co3O4 and can decrease the detection limit of CO to 1 ppm. CoOOH has a high selectivity of CO relative to H2 (Sco/SH2 ~ 4) and good linearity (R2 = 0.9903) for CO concentration range from 1 to 1000 ppm. The optimum working temperature (~80 °C) of CoOOH is lower than some semiconductor oxide on reviews.
A Quick View of Current SPM Industry [ 下載 PDF ]
Ming Yen Lin
Nanotechnology has been expected as one of the new technology that may lead to the next industrial revolution in the first decade of the 21th century. The invention of STM and other SPM in 1980s have provided the capabilities required for the measurement and manipulation of nanostructure and also sparked excitement throughout the scientific and industrial communities. In this article, an official marketing research provided by the Japanese government that describes the SPM related technologies, applications, worldwide market size, patents and competitors are briefly introduced. Also, the current profile of local SPM industry is described.
