**3.2 Simulation module**

Once the user has selected the diffracting object, the corresponding computing window is displayed. For instance, Fig. 2 (a) shows the interface for calculating the diffraction pattern from vertical slits. As it can be seen, the main parameters are, in this case: number of slits, distance between slits, slit width, illumination wavelength, and observation distance for near-field (Fresnel) or far-field (Fraunhofer) diffraction computing. Similar parameters are shown for the rest of diffracting objects available.

2 Will-be-set-by-IN-TECH

The first tool developed explains the phenomenon of optical diffraction. Fig. 1 (a) shows the main window of this module. By clicking on the corresponding icon, the user can choose to study diffraction patterns produced by several classical apertures: square, circular, slit (single, or multiple). Pre-stored and/or user-defined images can be also used as diffractive objects.

The basis of diffraction is explained. Fresnel and Fraunhofer diffraction is explained using some typical apertures. For instance, Fig. 1(b) shows diffraction patterns for a single slit, multiple slits, and circular aperture, which in turn produces the well-known Airy disc.

✁ APPLICATION button brings the user to the Simulation module

MANUAL button launches the users's manual of the tool. ✁

(b) Theoretical explanation of diffraction

✄ ✂

 ✁ Next

The user can navigate back and forth through a multi-page environment using the

**3. Diffraction tool**

**3.1 Theoretical module**

 ✁ Previous buttons.

described in section 3.2. The

✄ ✂

(a) Main menu of the diffraction tool

shown for the rest of diffracting objects available.

**3.2 Simulation module**

Fig. 1. Diffraction tool: main screen and example of the theoretical module

Once the user has selected the diffracting object, the corresponding computing window is displayed. For instance, Fig. 2 (a) shows the interface for calculating the diffraction pattern from vertical slits. As it can be seen, the main parameters are, in this case: number of slits, distance between slits, slit width, illumination wavelength, and observation distance for near-field (Fresnel) or far-field (Fraunhofer) diffraction computing. Similar parameters are

✄ ✂

and ✄ ✂ The intensity of the computed diffraction pattern is shown on the right-side image frame in Fig. 2 (a). Such diffraction pattern can be sent to a printer, or stored as an image file on the PC for further processing. By clicking on Cross section, a profile of the intensity diffraction pattern can be plotted, as shown in Fig. 2 (b).

(b) Cross-section of the computed diffraction pattern

(a) Fraunhofer pattern for 5 vertical slits illuminated with red light

Fig. 2. Example of far-field diffraction pattern computed for 5 vertical slits
