Multiple surface plasmon resonances are experimentally observed for p-polarized as well as s-polarized incident light at the planar interface of a metal and a chiral sculptured thin film. These experimental results confirm that four surface plasmon resonances can be supported at the interface of metal-chiral sculptured thin film. Multiple surface plasmon resonances may allow for multiple simultaneous measurements by devices that utilize surface plasmon resonance for detection.
Structural colors are non-pigment colors that originate from the scattering of light from ordered microstructures,
thin films, and even irregular arrays of scatterers. Examples include the flashing sparks of colors in opals and
the brilliant hues of some butterflies such as Morpho rhetenor. Structural colors arise in nature from one or more
of a palette of physical mechanisms that are now understood quite well and can be implemented industrially to
produce structurally colored paints, fabrics, and cosmetics.
For many years, there was no stand alone course in optics at Millersville University (MU). In the fall of 2007, the Physics Department offered for the first time PHYS 331: Fundamentals in Optics, a discovery based lab course in geometrical, physical and modern optics. This 300-level, 2 credits course consists of four contact hours per week including one-hour lecture and three hours laboratory. This course is required for BS in physics majors, but is open also to other science majors, who have the appropriate background and have met the prerequisites. This course deals with fundamental optics and optical techniques in greater depth so that the student is abreast of the activities in the forefront of the field. The goal of the course is to provide hands-on experience and in-depth preparation of our students for graduate programs in optics or as a workforce for new emerging high-tech local industries. Students learn applied optics through sequence of discovery based laboratory experiments chosen from a broad range of topics in optics and lasers, as the emphasis is on geometrical optics, geometrical aberrations in optical systems, wave optics, microscopy, spectroscopy, polarization, birefringence, laser generation, laser properties and applications, and optical standards. The peer-guided but open-ended approach provides excellent practice for the academic model of science research. Solving problems is embedded in the laboratory part as an introduction to or a conclusion of the experiment performed during the lab period. The homework problems are carefully chosen to reflect the most important relations from the covered material. Important part of the student learning strategy is the individual work on a final mini project which is presented in the class and is included in the final grading. This new course also impacted the department’s undergraduate research and training programs. Some of the individual projects were extended to senior research projects in optics as part of the senior research and seminar courses, PHYS 492 and PHYS 498, which are required for graduation for all physics majors. The optics course also provides basic resources for both research and training in the classical and modern optics of high-school students and K-12 teachers. The successful implementation of the optics course was secured by a budget of about $60,000.
A discovery based lab course in applied optics was developed and will be offered for the first time at Millersville University (MU) in the fall of 2007. The course will deal with fundamental optics and optical techniques in greater depth so that the student is abreast of the activities in the forefront of the field. The goal of the course is to provide hands-on experience and in-depth preparation of our students for graduate programs in optics or as a workforce for new emerging high-tech local industries. The new 300 level course will be required for BS physics majors, but will be open also to the full spectrum of science majors, who have the appropriate background. The optics course consists of four contact hours per week including a one-hour lecture and a three-hour lab. Students will learn applied optics through sequence of discovery based laboratory experiences. The guided but open-ended approach provides excellent practice for the academic model of science research. The lab experiments are chosen from a broad range of topics in optics and lasers, as the emphasis is on geometrical optics, geometrical aberrations in optical systems, wave optics, microscopy, spectroscopy, polarization, birefringence, laser generation, laser properties and applications, and optical standards. The starting budget of about $60,000 provided state-of-the-art lab equipment from Newport Co. and MICOS Co. The attraction of the course is shown by the active registration among physics, chemistry and biology majors.
The incessantly growing demands for higher speed of the wireless telecommunications and more compact devices require using of thin compound semiconductor wafers. The dicing is the very last process of the wafer manufacturing. At this stage the IC pattern is completely built up and the wafer has the highest value. Therefore, the goal of the singulation process is to provide the highest possible throughput. The conventional saw techniques "struggle" at their speed limits, while the conventional laser is not an appropriate dicing tool due to the strong thermal effect and big heat affected zones. The water-jet guided laser technology provides cool laser dicing since the laser is coupled in a fine stable water-jet and conducted to the work piece by means of total internal reflection like through an optical fiber, as the relatively low water pressure (10 - 30 MPa) of the tiny jet with diameter 40 - 100 μm results in a negligible force on the sample. This technology provides higher cutting speeds and burr-free kerf quality. By means of the Laser MicroJet, wafers as thin as 25 μm could be diced in streets of 50 μm width, with almost 100% wafer throughput. Here we compare the water-jet guided laser cutting with conventional techniques for dicing of thin semiconductor wafers. The results for Silicon and GaAs/Ge wafers are discussed in terms of speed, kerf quality and die fracture strength.
Several kinds of disks, such as DVD, MO and/or CD-R, for the next generation require high quality of plastic surface. Especially their flatness is very important. Here a disk inspection system is proposed using 2D birefringence distribution measurement. Small birefringence is a serious problem that is caused by internal strain, and/or residual stress. Moreover it is possible to observe its molecular orientation. The birefringence measurement is necessary to determine the relative retardation and the azimuthal angle of the fast axis in an optical disk. Several images captured by a CCD camera are enough for one birefringence distribution analysis. Experimental procedure and their results of some famous optical disks are discussed.
Thin (approximately equals 1.5 micrometer) CdS films were prepared on glass by laser ablation using fluences of 2 - 5 Jcm<SUP>-2</SUP>. We demonstrate that such an increase of the laser fluence turns the orientation of the c-axis of the films from perpendicular to parallel with respect to the substrate surface. The influence of this orientation variation on the optical properties of the films is studied by photocurrent, transmission and z-scan measurements. All experiments were carried out at 300 K using monochromatic light or the cw emission of argon and He-Ne lasers at 514.5 and 632.8 nm, respectively. The transmission threshold and the photocurrent maxima are shifted to shorter wavelengths and the transmission edge becomes steeper with increasing the laser fluence. The nonlinear absorption and refraction indices were evaluated for 514.5 nm and 632.8 nm by z-scan technique. It occurred that at 514.5 nm the photo-thermal heating due to effective absorption dominates and, therefore, refractive nonlinearities are not provable. At 632.8 nm, however, the samples are transmissive and refractive nonlinearities are clearly observed. Higher nonlinear coefficients of absorption and refraction were found for samples with parallel c-axis. As far as we are aware, this work represents the first study of the influence of the crystal direction on the photocurrent and z-scan features of oriented thin CdS films.