Laser based manufacturing of optical diffusers

Alqurashi, Tawfiq (2019). Laser based manufacturing of optical diffusers. University of Birmingham. Ph.D.

Preview

Alqurashi2019PhD.pdf
Text - Accepted Version
Available under License All rights reserved.
Download (11MB) | Preview

Abstract

High-quality optical diffusers provide a solution for a variety of applications requiring Gaussian and non-Gaussian intensity distributions, including usage in aerospace, for displays, imaging systems, and for biomedical optics. Advances in laser machining processes have enabled the rapid production of efficient optical diffusers. Three types of laser machining processes: CO₂, nanosecond, and femtosecond laser machining were utilized to fabricate the optical diffusers, mainly on float glass on which these processes produced nano and microfeatures allowing the light to be scattered. Also the float glass is an inexpensive material compared to fused silica and quartz glasses. But some other diffractive optical devices were fabricated on polycarbonate (PC) material. The reason the optical diffusers were not fabricated on polycarbonate (PC) and polyethylene terephthalate glycol (PETG) materials is that the areas treated with the laser became opaque, not allowing light to be scattered thoroughly.

Furthermore, we describe the design and experimental realization of mechanically stretchable and tunable optical diffusers. These intrinsically designed diffusers (based on cylindrical lenslet and micro tip arrays) were made directly on elastomer material using laser ablation. The dimensions of both the tips and the lenslet arrays play a critical role in the distribution of illumination and wettability resistance. By stretching the diffusers mechanically along the lenslet arrays, diffusion angle tuning was achieved along with a revisable change between hydrophilic to superhydrophobic states providing self-cleaning properties. These multifunctional diffusers constitute an important step towards integration with flexible materials or devices, such as stretchable organic light-emitting diodes (OLEDs) and polymer light-emitting diodes (PLEDs).

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):