Now we will assemble two versions of a diffraction spectroscope with our own hands. A spectroscope is a device that allows you to study the spectrum of light by dividing its spectral components along a certain axis. Light can be divided into monochromatic waves either through the phenomenon of dispersion or diffraction. In this case we will use diffraction, since we have an excellent diffraction grating on hand - a CD!
We will need a small cardboard box, a CD, glue, and an opaque tube for the eyepiece.
Using scissors, cut a piece of the CD to fit the size of the box:
Let's mark the box so that the eyepiece can be installed correctly. From optics we know that the angle of incidence is equal to the angle of reflection. But this way we will see a window through which light will pass, and not diffraction maxima, so we will leave a space to the right of the line of the future window.
Then, closing the box, we will select a suitable place to introduce light. To do this, we will carefully pierce a hole and observe through the eyepiece. If we see directly reflected light in the eyepiece, then we seal the hole and pierce a new one a little further. And so on until many colored dots lined up along the line are visible in the eyepiece. Then we’ll cut a window:
Let's install a light knife made of two razor blades on the window - so that the narrowest beam of light gets into the box - this way we will see the clearest picture possible.
If everything worked out, then we will see a diluted spectrum in the eyepiece. If the spectrum is not continuous (for example from LDS or gas-discharge lamps), then we will see a set of lines. Each line is a monochromatic component. In the photo, the very top line is actually deep purple, the camera just distorted the color.
Option two
Let's make a miniature spectroscope that works in transmitted light. To do this, cut out a CD as in the first option:
Use tape to remove the reflective backing:
We will paste the resulting diffraction grating instead of one of the walls of the matchbox:
On the opposite side we will also design a light knife:
The resulting spectroscope also spreads the spectrum, although the observation is somewhat worse.
