Diffraction of Light: θ and λ Relationship

[BigMonkey]

Good day,

I happened across an interesting interactive JAVA applet demonstrating the diffraction of light through a slit. (http://micro.magnet.fsu.edu/primer/java/diffraction/basicdiffraction/index.html" ) Associated with it was the equation,

sin θ = λ/d

where d is the width of the slit.

My question is, what is the relationship of the θ to λ when there is no slit, i.e., the wave is diffraction around a object in the path of the wavefront?

 

[BigMonkey]

Hey, if you guys can write lengthy responses on the equations of Maxwell, this should be a cake walk!



Who's up for some optics!?

 

[jtbell]

In the spirit of the "teach a man to fish" saying...

Pick one phrase from list A and one phrase from list B, and Google on the combination:

list A:
"Fraunhofer diffraction"
"Fresnel diffraction"

list B:
"circular aperture"
"rectangular aperture"
"knife edge"

And for good measure, Google on "Poisson spot".

 

[BigMonkey]

I honestly don't have the time to devote to sifting through articles, dissertations, and poorly maintained university demonstrations just to find an approximate equation for something as common as knife edge diffraction.

Some of the equations that I do see make me shudder (particularly the ones on the Wolfram site). You see, my math only progressed to low-level calculus.

Should anyone happen to crack open a physics book in the next week or so and find something, please post it.

I appreciate the info, though.