- #1
Schreiber__
- 4
- 1
- Homework Statement
- Fresnel lens Part 1: You would like to design a 25 mm diameter blazed Fresnel zone plate with a first-order power of +1.5 diopters. What is the lithography requirement (resolution required) for making this lens that is designed for 550 nm? Express your answer in units of 𝜇𝑚 to one decimal point.
Fresnel lens Part 2: What would the power of the first diffracted order of this lens be at wavelength of 400 nm? Express your answer in diopters to one decimal point.
- Relevant Equations
- M = lambda/NA = (lambda*f)/r_n -> Part 1
f = r^2/(n*lambda) -> Part 2
For the first part, I got correct:
M = (lambda*f)/r_n
Converting units to meters (m) then plugging them in:
(550x10^-9 m) * (0.67 m)/(0.0125 m) = 2.948x10^-5 or 29.48x10^-6 m or 29.48 nm
This checked out.
For the second part, using the information from the first part:
f = r^2/(n*lambda) = (0.0125 m)^2/(1*400x10^-9m) = 390.625
To calculate the power in diopters we take 1/f = 1/390.625 = 2.56x10^03 ! This seems too small of a value.
I am missing something here or have used an incorrect expression.
Thanks for the help!
M = (lambda*f)/r_n
Converting units to meters (m) then plugging them in:
(550x10^-9 m) * (0.67 m)/(0.0125 m) = 2.948x10^-5 or 29.48x10^-6 m or 29.48 nm
This checked out.
For the second part, using the information from the first part:
f = r^2/(n*lambda) = (0.0125 m)^2/(1*400x10^-9m) = 390.625
To calculate the power in diopters we take 1/f = 1/390.625 = 2.56x10^03 ! This seems too small of a value.
I am missing something here or have used an incorrect expression.
Thanks for the help!
