Lens that will make the rays parallel to each other

i need a lens that will make the rays parallel to each other & focal point at infinite.without much loss in the intensity.collimator lens kind of action but not at the cost of intensity.
 

K^2

Science Advisor
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Re: Lens

Very easy. A lens with a focal point at infinity is called a window.
 
Re: Lens

See the fig(attachment).I want to achieve this(shown in fig).
 

Attachments

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Re: Lens

That's just a normal lens, ray lines are independent of the direction of light.

I didn't realise collimators had any loss of intensity, are you using laser light or just a point source?
 
Re: Lens

That's just a normal lens, ray lines are independent of the direction of light.
i am not getting this.



Its not laser light it is the output from a parabolic antenna.with the beam angle of about 10-15degree.
 
Re: Lens

I 'm not sure i fully understood your question but you try using two lenses.
The 1st (focal length f1) to focus the light at a point and the 2nd (focal length f2) to get a parallel ray output.
The 2nd lens must be placed with its focal length at the focus point of the 1st i.e., at a distance f1+f2 from the 1st.
 
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Re: Lens

What frequency are we talking about?
 
Re: Lens

microwave.have heard somewhere all the emwaves have the same properties as light.parabolic antenna is an example of that,as reflection of radio-microwaves is observed here just like light.
 

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