= Solution
For the narrow pair, the amplitude is $e^{-iqd/2}-e^{iqd/2}=-2i\sin(qd/2)$. Hence <phase-reversed double-slit diffraction> gives
$$
\boxed{I(\theta)\propto4\sin^2(\pi d\sin\theta/\lambda).}
$$
There is a central dark fringe. Minima obey $d\sin\theta=m\lambda$, maxima $d\sin\theta=(m+1/2)\lambda$, and the near-axis angular fringe period is $\lambda/d=0.005\,\mathrm{rad}$. Finite slit widths multiply this interference profile by their single-slit envelope. The parent plot includes the narrow-pair profile.
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