Glass is used in various applications. However, mechanical machining of glass is difficult because of its
brittleness. Laser machining serves as an important alternative processing method. In addition, laser may
be employed to create internal features within the glass substrate without any damage to the glass
surface.
You are to (i) drill holes on a 1mm thick fused silica glass, and (ii) to create a subsurface pattern (i.e. near
but beneath the surface) within the glass substrate without damaging its surface. The transmittance vs
wavelength of light for the fused silica glass is shown in Figure 1. To realize tasks (i) and (ii), you have to
arrange for the appropriate laser system(s) and the associated optical arrangement(s).
(a) Suggest one suitable laser system to perform both tasks (i) and (ii), or two different laser systems to
perform task (i) and task (ii) separately.
(b) For your suggestion in (a), your arrangement and choice of the optical system(s) to carry out the tasks,
namely a beam expander with a wide numerical aperture focusing lens, and/or a narrow numerical
aperture focusing lens with long focusing distance. In addition, you might also like to suggest other
alternative arrangement(s).
For your answers to (a) and (b), please provide explanations and justifications carefully. Discuss also the
relative advantages and disadvantages of having one OR two different laser systems for your answers to
(a)
Sample Solution