A puzzle on light diffraction

1. Dec 13, 2009

lionelwang

Hello!
Recently, I'm always thinking about why diffraction effects are generally most pronounced for the size of the diffracting objectsis that is on the order of the wavelength. How about a relatively bigger object?

I try to find it everywhere I can but failed. So anyone can help? Thanks!

2. Dec 13, 2009

FoxCommander

Can you explain a bit more? what kind of objects are you talking about?

3. Dec 13, 2009

lionelwang

such as bending of waves around small obstacles and the spreading out of waves past small openings.
A famous example:single-slit diffraction. If the slit is pretty large, then I guess there is no abvious diffaction.

4. Dec 13, 2009

Staff: Mentor

5. Dec 13, 2009

Andy Resnick

The wave propagation of light is parameterized in terms of a specific length scale (the wavelength). That means the problem is in terms of ratios: wavelength/distance, for example. If wavelength/distance <<1, the appropriate diffraction term is small, while if wavelength/distance >>1, it's large. Note that 'distance' can be propagation distance, the size of a scattering object, or aperture diameter...

Does that help?

6. Dec 14, 2009

lionelwang

I think you are right, thank you very much!