Some of the wave will be absorbed at each of the absorbers but some will continue through the gap.  The smaller the gap the less will get through.  With absorbers there is not so much of a big change with less than or more than a wavelength gap.  However, the velocity in the absorber will probably be slower than in air so there will be refraction into the absorber which affects the first half wavelength from the surface most strongly.  However, there will be some curvature of the wavefront in any case, as power moves sideways towards the absorber on either side.

With metal boundaries there would be polarization effects - electric field across the gap goes through ok, close to speed of light, but electric field along the gap will not go through if the gap is less than a half wavelength, and slower than the speed of light if more than a half wavelength.

There may be some of the same kind of polarization effects with absorbers depending on their impedance/density/type.

Generally a wave will reflect from a hole that is smaller than the wavelength. A slit may split the wave such that the component polarized parallel to the slit will pass through and the remainder will be reflected.

The absorber will warm up and radiate as a black body. Reflectors nearby do not warm up or radiate. Most materials have a percentage reflection for a given wave length and absorb the remaining percentage of the wave. So most black body radiation will be longer waves than the incident wave.

Wavelength is SPATIAL – i.e. dimension is space METERS! Hence, hole size opening matters for the wavelength to pass partial or full. Changing hole size is passing wavelength and that will modulate wavelength or change wavelength.  Imagine a honey bee with only one wing or wings stripped or legs cut off to pass through small hole openings. It’s still honey bee but modulated in space (dimensions changed)! Wavelength is at the entrance and exit of material change holes or boundary conditions.

Frequency is TEMPORAL – time (Hertz = 1/Seconds), hence space size hole opening does not matter for frequency to pass through. Material’s natural vibration will interact to produce frequency modulations effects within the material but not at the  boundary of penetration. Frequency is within the material effect!

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EMF waves have both oscillating Electrical (E), say X-direction; and oscillating magnetic field (M) say in Y-direction - and hence are orthogonal

EMF or light wave propagates along the Z direction that is normalized to both E & M field

Two states of polarization are orthogonal to each other and may get separated in time with due to Refractive Index of material such as in fiber optic and cause pulse DISPERSION or pulse spread due to delays in arrival at the destination.

Hole opening affect:

1. Let us refer back to our high school physics - pin hole camera and think about it! http://slideplayer.com/slide/7711402/

2. Read about great Physicist Isaac Newton - small hole for small cat and big hole for big cats! In an apparent early modern example of urban legend, the invention of the pet door was attributed to Isaac Newton (1642–1727) in a story (authored anonymously and published in a column of anecdotes in 1893) to the effect that Newton foolishly made a large hole for his adult cat and a small one for her kittens, not ...

3. In army tanks, navy ships and air-force fighter jets the "source of strongest EMF signature is SMALL APERTURES" - smaller the opening, large the EMF radiation, why?

4. EMF radiation is inversely proportional to opening radius - what is this critical radius like critical angle on fiber optic for total internal reflections - this is related to the wavelength!

Example - imagine a hole large than honey bee wing span and  hundreds of bees are eager to go in and out simultaneously through the hole!

Decrease the hole radius to fit only a single bee to observe that a swarm of bees will be waiting to get in or out of the hole ---- or sent back, REFLECTION!

Hole opening is smaller than the bees’ wingspan or body with folded wings ... bees may partially be in and out or peek-a-boo!! Partial penetration and maximum reflection.

A- BEE are motion in Z- direction - like EMF wave travelling

B- BEE wings are E-field - Wings have components of polarization

C- Bees Legs fully stressed and elongated through the body are Magnetic or H field - legs will also have component of polarization

D- wings oscillation is the Frequency of Electric filed, so also the legs oscillations represent Magnetic field oscillation - assume them to be same as Electric filed oscillation

Conclusions - when bees cannot enter the hole, large bee presence crowd the opening, smaller the opening large crowd of bees - similarly large EM waves are crowded at the smaller openings and hence source of EMF signatures. They will also heat up the opening, 

If the opening is large enough then smaller delay and reflection. If hole is very large than nothing since to bees are not waiting or crowding the hole entrance, so also EMF field is waiting or reflected but rather maximum penetration and minimum reflection.

Wavelength is SPATIAL – i.e. dimension is space METERS! Hence, hole size opening matters for the wavelength to pass partial or full. Changing hole size is passing wavelength and that will modulate wavelength or change wavelength.  Imaging bee with only one wing or wings stripped or legs cut off to pass through small hole openings. It’s still bee but modulated in space!

Frequency is TEMPORAL – time (Hertz = 1/Seconds), hence space size hole opening does not matter for frequency to pass through. Material’s natural vibration will interact to produce modulations effects.

Jerry is mistaken in his description - light goes quite well through holes in good conductors that are about 3/4 of a wavelength across (look up circular waveguide, these are also used as well-matched antenna feeds), and will go through round holes about 2/3 of a wavelength across and rectangular holes just over half a wavelength across. If the holes are in absorbers then the radiation may go through holes considerably smaller because the electric field does not have to fall to zero at the edges of the hole.  Whatever gets into the hole may end up being absorbed in the walls of the hole or getting out the other end, depending on the thickness and the properties of the absorber.