Bryan K. A. Ngoi

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Ultrashort pulsed laser material processing is a new micromachining method that is gaining interest. Its capability of submicrometer machining has been proved. To obtain high speed and highly flexible beam steering, a two-axis acousto-optic deflector is employed. However, dispersion associated with acoustic-optic interaction will cause serious spatial(More)
Safe and effective laser ophthalmic surgery requires a fine balance between the efficiency of laser delivered and the degree of collateral side damage. The laser–ocular tissue interaction process is reliant on three main variables, namely, wavelength, pulse duration, and deposited energy. A certain amount of energy is needed to achieve ablation, while too(More)
A modification of phase-shifting interferometry is proposed for microsurface profiling of flat surfaces under vibrating conditions. With this technique the required phase shift, achieved by quarter-wave plates and polarizers, is free of errors associated with motion. A nearly common optical-path configuration is achieved, and the effect of environment is(More)
BACKGROUND AND AIMS OF THE STUDY Mechanical heart valves (MHV) are widely used to replace dysfunctional and failed heart valves. The bileaflet MHV is very popular due to its superior hemodynamics. At present, bileaflet MHVs account for about two-thirds of the prosthetic heart valve market. Since their introduction in 1977, the hemodynamics of bileaflet(More)
Handgrip strength is an easy measure of skeletal muscle function as well as a powerful predictor of disability, morbidity, and mortality. In order to measure grip strength, a novel fiber-optic approach is proposed and demonstrated. The strain-dependent wavelength response of fiber Bragg gratings has been utilized to obtain the strength of individual(More)
The unique ability of the ultrafast lasers to perform sub-spot size machining has been proved to be advantageous over conventional lasers for sub-micron-machining. To achieve this, a Gaussian laser beam free of spatial defects is essential. In this research work, submicron holes with clear edge and symmetric shape on thin metal films using a Ti:Sapphire(More)
Femtosecond laser pulse has been used for the machining of the gratings primarily due to its superior advantages over conventional continuous wave (CW) and long pulse lasers for micromachining. In this paper, we develop a novel technique for the fabrication of planar gratings by colliding two beams to generate interference fringes. This technique is simple,(More)