Reducing spherical aberration

[fantagero88]

Homework Statement

- single lens
- f=50cm
- refractive index n=1.53
- if object placed 70cm, find the radii of curvature for the two surfaces of the lens which would minimise spehrical aberration

Homework Equations

what i got from my notes

refraction at a spherical surface

(n1/so+n2/si)=((n2-n1)/R)+h²[(n1/2so)(1/so+1/R)²+(n2/2si)(1/R-1/si)²]

this is after using the third order theory

The Attempt at a Solution

i tried to make another equation for the other side of the refractive surface and then added them together,
and also, tried to use r= infinity because i read that plano-convex can reduce SA.

but still i could get it on what kind of value that could show me when SA is minimised. and also, i couldn't get rid value for h, which the value is not given.

is minimising SA is to get the complete thins lens equation from the third order theory??

thank you

 

[fantagero88]

i found the answer..
damn, i lost one piece of my note.. no wonder i was lost.

so, what i did i just used bending factor to get the radii.
i'll try to post up the answer then i got back home
thanks

 

[nlightner]

for your time and attention.Dear student,

Thank you for sharing your attempt at a solution. When it comes to reducing spherical aberration, there are a few approaches that can be taken. One approach is to use a lens with a larger aperture, as this will reduce the amount of light that is bent at the edges of the lens, thereby reducing spherical aberration. Another approach is to use a lens with a smaller focal length, as this will also reduce the amount of light that is bent at the edges of the lens.

In your case, you have a single lens with a focal length of 50cm and a refractive index of 1.53. To find the radii of curvature for the two surfaces of the lens that would minimize spherical aberration, we can use the lensmaker's equation:

1/f = (n-1) * (1/R1 - 1/R2)

Where f is the focal length, n is the refractive index, and R1 and R2 are the radii of curvature for the two surfaces of the lens. In this case, we can rearrange the equation to solve for R1 and R2:

R1 = (f * (n-1)) / (n * (n+1))
R2 = (f * (n-1)) / (n * (n+1))

Plugging in the values for f=50cm and n=1.53, we get:

R1 = 20.3cm
R2 = -20.3cm

This means that the first surface of the lens should have a radius of curvature of 20.3cm and the second surface should have a radius of curvature of -20.3cm. Keep in mind that these values are for a lens with a spherical surface. If you are using a lens with a different shape, the radii of curvature may be different.

In conclusion, to minimize spherical aberration in your single lens system, you should use a lens with a focal length of 50cm and two surfaces with radii of curvature of 20.3cm and -20.3cm, respectively. I hope this helps. Good luck with your studies!

Best regards,

[Your name]