Simple optical system for manufacturing point diffraction interferometer plates in titanium films using a low intensity CW laser beam

We propose an optical system for making pinholes in titanium films for applications in point diffraction interferometry. The optical system for fabrication is easy to implement and to align and, as a result of this, it is possible to obtain pinholes in the range of 1 to 8 μm of diameter. The technique is based on laser ablation and, since we use a green laser, the spot produced by the focus of the optical system can be observed. Also, the damage over the titanium film can be monitored with the aid of a microscope objective lens in real time. The new technique is described and the resulting plates with the pinholes are shown. A successful application of the plates in interferometry is presented as well.