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Archived Theses
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DOIs Assigned
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DOI Rate
Discipline
Design and fabrication of high-power laser diode bar
Semiconductor lasers have emerged as a transformative technology replacing conventional methods with their rapid evolution and widespread integration across various industries. It is increasing its impact in the industry involving material processing, tempering, annealing and bending. Laser diode bars are increasingly utilized in these processes, offering the advantage of easily adjusting the optical power and beam dimensions to meet specific requirements. This thesis as part of the TUBITAK-1004 project, investigates the details of laser diode bar fabrication for a system designed to execute heat treatment processes on glass surfaces. Utilizing high-power laser diode bars, the goal is to achieve optical power exceeding 100 W using 1-cm bars. The focus is to apply heat treatment by these bars to glass surfaces containing coatings with silver layers, a task traditionally implemented with large and energy-intensive furnaces. In contrast to traditional techniques, the use of laser diode bars provides precision targeted heating, considerably reducing energy usage and processing time. Heat distribution management in various glass treatments has the potential to transform the glass industry by adding flexibility to the relevant processes. This thesis demonstrates the fabrication of high-power laser diodes achieving an output power of 158 W, also showcases their practical application. The conducted heat treatments on coated glass surfaces are analyzed. The outcomes presented in this study demonstrate an outlook of the implementation of these laser diodes for industry.
Static logo projection lamp optical design for automotive lighting applications
Projection lamps are a lighting technology that has been used in the automotive industry in recent years, providing the opportunity to get in and out of the vehicle safely by illuminating the surroundings of vehicles with a logo image, and aiming to minimize accident rates by reflecting turn and reverse signal lights on the ground. In this study, which was carried out by considering the Köhler lighting concept, which is one of the design approaches of modern illumination systems, light emitting diode (LED) was used as the illumination source. In the automotive lighting industry, polymer materials and injection molds are used to easily produce light-bending surfaces and enable mass production at low cost. In the design of the system, the optical properties of the polymer materials (Polycarbonate (PC) and Polymethyl methacrylate (PMMA) to be used in lenses and the limitations of injection molding technology were used as input in ANSYS Zemax OpticStudio, an optical design and analysis program. This logo lamp, located inside the exterior rearview mirror housing, has dimensional restrictions due to other components inside the mirror. For this reason, the number and size of lenses to be used in optical design are designed to be as small as possible while providing sufficient optical output performance. Thus, the optical design and performance analysis of a logo projection lamp that complies with the design requirements, has a compact structure with three lenses, optimized optical deviations and uniform light intensity distribution were carried out.
Spaceborne tele-objective design for earth imaging
This thesis presents an electro-optic camera design to fit into a 6U CubeSat platform for Earth observation from the low Earth orbit (LEO). The design is aimed to achieve a 4.5 m ground sampling distance (GSD) at 400 km altitude. The optical design of the camera is based on a refractive, telephoto objective architecture consisting of six spherical lenses whose optical materials are compatible with the space environment. An F/5.5 telephoto objective, near diffraction-limited performance over 2.6-degree of the full field of view (FFOV) is optimized utilizing a ray-tracing software (i.e., OpticStudio) for panchromatic imaging between the spectrum of 450 – 700 nm. A commercial, complementary metal-oxide semiconductor (CMOS) 2-D imaging sensor is selected to provide a better than 15 km swath width. A tolerance analysis of the optical design has been carried out to identify limitations related to the alignment and optical manufacturing. The modulation transfer function (MTF) and signal-to-noise ratio (SNR) budgeting analysis are also performed to show the performance of the electro-optic camera design.
Design and production of a free form lens for long-range illumination
In this study, we design and manufacture new prototype of a LED Projector containing Free Form Lenses to cover both visible and infrared regions for the long-range illumination. The geometrical form of the lens is obtained by minimizing the optical path length for the light rays emitted from LED. The lens is produced by the plastic injection method using PMMA material whose transmittance for the concerned optical region is greater than 90%. The optical measurements of the lens is compared with the simulation based on ZEMAX 2009. It is found that, although there are some production errors and LED alignment problems, the optical measurements of the lens are close to the predicted values in the design.
A meridional ray tracing software development for lens design
In this thesis a simple meridional ray tracing software which can be used in the optical lens design is developed. The first version of this software is called Heysem 1.0 which has both paraxial and exact ray tracing capability. Heysem has a simple Graphical user Interface (GUI) to input the lens radii, thickness, number of rays and etc required in the design. It gives some output the system layout, a summary table and some basic lens aberration calculations and plots to the user. The outcomes and plots obtained in heysem are compared with zemax OpticStudio program. It is found that the ray tracing computations and plots in both softwares are the same.