Apparatus for Studying
Diffraction from Reflection Grating

This device is specifically designed for studying reflection gratings. It consists of a laser head mounted on a kinematic holder and a grating mount with angular adjustments. The grating can be fixed at appropriate angles using this mount. Fine adjustments in grazing or incident angle can be done using kinematic tuning of the laser mount.

Both the laser and grating mounts are fixed on rail carriers, which are held on a graduated solid aluminum rail. The diffraction pattern is projected on a screen or wall. When a meter scale is used as reflection grating, the pattern can be observed typically at two to three meters.

Compact Disc and the meter scale consists of a series of evenly spaced (reflective) grooves and ridges that act as a diffraction grating. The grooves in a compact disc are very close together. (The tracks of a compact disc act as a diffraction grating, producing a separation of the colors of white light. The nominal track separation on a CD is 1.6 micrometers, corresponding to about 625 tracks per millimeter. This is in the range of ordinary laboratory diffraction gratings.) CD and the millimeter scale are reflective and therefore the diffraction pattern can be observed by looking at the reflected pattern. The spectrum of colors can be seen reflected from a compact disc. The closely-spaced tracks on the surface of the disc form a diffraction grating, and the individual wavelengths of white light are diffracted at different angles from it.

Experiment:

   To measure the wavelength of laser light using a millimeter scale as grating
   To find the groove spacing of CD

Features:

Sharp, clearly visible diffraction pattern

Simple, economical and relatively compact

Specimen holder provides angular and height adjustment

Fine adjustments in grazing angle can be done using kinematic laser mount

Drawings:

Scope of Delivery:

Optical Rail

Kinematic Laser Mount

Specimen Holder with Mount

Reflection Gratings

Diode Laser with Power supply (Red)

Accessories

User Manual