Simplest lens set up to reveal optical spectra of an object

In summary, the conversation discusses a laser experiment with a grating and a lens, which creates an image of the grating. The speaker has questions about the purpose of additional lenses in the setup and is looking for a simpler setup with only two lenses and a grating. They also mention the possibility of using a beam expander/collimator in the setup. The expert suggests that a single convex lens is all that is needed for the experiment.
  • #1
houlahound
908
223
I have done basic experiments where a laser is shot thru a grating and a lens is inserted at the diffraction pattern to put the spectra back together and form an image of the grating. apart from this being the single most mind blowing experiment ever to witness I have some questions about the lens set up's.

the experiments I did were standard undergrad (I think) done on a optical bench with converging lenses.

the set up involved a bunch of extra lenses in front of the laser and at the image end. I can not figure what all these extra lenses are for apart from maybe bringing the image into a convenient distance that whoever write the experiment figured out in advance.

I am not interested in what these lenses do but am interested in the simplest set up with hopefully 2 lenses and a grating where I can get an image of the grating or an image of the spectra by just adding/removing one lens to switch between the two desired images all at a practical distance to the final image plane.

anyone got any references/links/posts to a simple lab set up without all the extra who knows what for lenses added.

cheers any info
 
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  • #2
Why did you not ask someone what all those lenses are for?

I would not be surprised if the setup contained a beam expander/collimator. A laser light from most sources is a thin, pencil beam, and to make it go through a wide coverage of a grating, you have to expand it.

The simplest experiment is still with just ONE convex lens if the laser spot size is big enough. That is all you need, in principle.

Zz.
 

Related to Simplest lens set up to reveal optical spectra of an object

1. What is the simplest lens setup to reveal optical spectra of an object?

The simplest lens setup to reveal optical spectra of an object is a basic refracting telescope. This consists of two lenses - an objective lens and an eyepiece - placed at either end of a tube. The objective lens collects and focuses light from the object, while the eyepiece magnifies the image formed by the objective lens. This setup can easily reveal the optical spectra of an object by separating the different wavelengths of light.

2. Why is a refracting telescope considered the simplest lens setup for revealing optical spectra?

A refracting telescope is considered the simplest lens setup for revealing optical spectra because it only requires two lenses and a tube, making it relatively easy and inexpensive to construct. It also produces a clear and sharp image, making it ideal for observing optical spectra.

3. Can a simple magnifying glass be used to reveal optical spectra of an object?

No, a simple magnifying glass is not suitable for revealing optical spectra of an object. A magnifying glass only magnifies the image of an object without separating the different wavelengths of light. It also does not have the necessary lenses or focal length to produce a clear and detailed image of the object's spectrum.

4. Are there any other lens setups that can reveal optical spectra of an object?

Yes, there are other lens setups that can reveal optical spectra of an object, such as a compound microscope or a spectroscope. However, these setups are more complex and require specialized equipment, making them less accessible and practical compared to a basic refracting telescope.

5. Do I need any additional equipment to reveal optical spectra using a refracting telescope?

No, you do not need any additional equipment to reveal optical spectra using a refracting telescope. However, using a device called a diffraction grating can enhance the separation of the different wavelengths of light and provide a more detailed spectrum. This can be easily attached to the eyepiece of the refracting telescope.

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