The paper describes a portable, remote controlled Michelson interferometer using a laser pointer. The mirror on one of the arms was mounted on an encoded stepper motor. A motor driver controller circuit has also been fabricated, which is interfaced with a personal computer and that can be controlled through Web.
Real time structural health monitoring using fiber optic sensors is an interesting field of research in recent years. This paper presents the performance of fiber optic polarimetric sensor (FOPS) using plastic fiber. The experiments were conducted on concrete structures using plastic fiber sensor embedded in two different configurations. The dynamic responses of these sensors are experimentally evaluated under different conditions. Their performances are discussed for dynamic applications and the results are compared with that of glass fiber.
As a premier school, Raffles Institution (RI) seeks relevant and forward-looking educational initiatives. Bringing emerging technologies into the school encourages the students to cultivate skills and attitudes that will empower them to ride the present and future waves of information and technology most meaningfully and innovatively. Photonics has diverse applications in the modern technological world, and Singapore aims to become a center of excellence for optics and photonics in the region. However, a serious study of photonics begins only at the college level (K - 11/12). Entrusted with Singapore's brightest young minds, RI pioneered the development of a Photonics Exploratory Laboratory (X-LAB), being the first among secondary (K-7 to K- 10) schools in Singapore and possibly in the region. Young RI students are learning photonics fundamentals and recognizing photonics as a potentially rewarding field of study. With the expertise of lecturers from tertiary institutions, selected RI students are instructed in basic theory and trained in fundamental experiments. These students progress to embark on projects and in-depth studies under the wing of tertiary institutions and universities. Studies on Haidinger Fringes, Laser Doppler Anemometry and Optical Gratings have thus been successfully completed. Furthermore, the X-LAB acts as a focal point for students to experiment with Holography and Laser Animation.
Laser shows and beam effects have been a source of entertainment since its first public performance May 9, 1969, at Mills College in Oakland, California. Since 1997, the Photonics Center, NgeeAnn Polytechnic, Singapore, has been using laser shows as a teaching tool. Students are able to exhibit their creative skills and learn at the same time how lasers are used in the entertainment industry. Students will acquire a number of skills including handling three- phase power supply, operation of cooling system, and laser alignment. Students also acquire an appreciation of the arts, learning about shapes and contours as they develop graphics for the shows. After holography, laser show animation provides a combination of the arts and technology. This paper aims to briefly describe how a krypton-argon laser, galvanometer scanners, a polychromatic acousto-optic modulator and related electronics are put together to develop a laser projector. The paper also describes how students are trained to make their own laser animation and beam effects with music, and at the same time have an appreciation of the operation of a Class IV laser and the handling of optical components.
The principal aim of the Photonics Centre at NgeeAnn Polytechnic, Singapore, is to provide a broad-based and practice-oriented education and training in photonics and laser technology. Students who choose to do their final-year project in this field, do not have any photonics background at all at the start of their project. However, the Centre's project-based learning programs have been successfully tried and tested. Through a series of specially selected lectures and experiments, the students are eventually led into the project proper. By the time the students complete their project, they would have gained immense knowledge and hands- on experience in photonics and laser technology. Some examples of completed projects include development of a fiber laser using erbium-doped fiber, polarimetric sensors for damage detection of aluminum materials and concrete structures, development of holographic optical elements and external cavity semiconductor laser sensor. The students have gone on to participate in R&D competitions and have been awarded either the second or top positions. The aim of this paper is to examine the methodology used that has made this form of training successful.
Raffles Girls' Secondary School, Singapore has a Gifted Education Program whereby bright young women are given the opportunity to fulfill their potential by taking up a project in a tertiary institution. Ning Hwee Tiang is one of the science teachers in the Program who has seen the relevance of getting her students involved in optics and photonics. Basic optics is taught in Secondary 3 and this program helps the students to enrich themselves with other related concepts in optics, and its application. It also helps build links between what is learnt in class and the real world. The ultimate aim is to get them interested enough to join in this area, thus increase the women representation in Optics. This paper aims to show how the Photonics Centre, NgeeAnn Polytechnic has participated in their Program, the training methodology used to introduce difficult topics in optics and photonics, and the projects undertaken. Some of the projects include making transmission holograms, lasershows and sensor applications of the Michelson Interferometer.
Photonics has emerged as multidisciplinary technology of the future. Hence photonics has become an important course to be reckoned with in all disciplines of technology. We have developed a new basic and advanced lecture and laboratory course on optics, lasers, interferometry and fiber optics for mechanical engineers. This course is the primary senior level experimental physics course with emphasis on practical experience with necessary theoretical knowledge. The course is structured to cover the relevant topics in photonics, from wave nature of light to ultra short pulse generation, types of lasers and various applications.
The spectral characteristics of a diode laser are significantly affected due to interference caused between the laser diode output and the optical feedback in the external-cavity. This optical feedback effect is of practical use for linewidth reduction, tuning or for sensing applications. A sensor based on this effect is attractive due to its simplicity, low cost and compactness. This optical sensor has been used so far, in different configuration such as for sensing displacement induced by different parameters. In this paper we report a compact optical sensor consisting of a semiconductor laser coupled to an external cavity. Theoretical analysis of the self- mixing interference for optical sensing applications is given for moderate optical feedback case. A comparison is made with our experimental observations. Experimental results are in good agreement with the simulated power modulation based on self-mixing interference theory. Displacements as small as 10-4 nm have been measured using this sensor. The developed sensor showed a fringe sensitivity of one fringe per 400nm displacement for reflector distance of around 10cms. The sensor has also been tested for magnetic field and temperature induced displacement measurements.