Go to city hall, describe the problem without naming names, and check into bylaws. If she is violating some obscure bylaw, use the city's resources rather than your own. Elicit some sympathy; get a doctor's note about insomnia or some such thing.
I would like more information as to the location of the pole from your property line.
If you find out the type of bulb, you may be able to blast it with some type of wave so it keeps burning out. She's blasting you with light waves, so don't lose any sleep about using the same sort of method.
If the light pole is very close to the property line, you could just erect a small sheet of plywood on a pole. It would be perfectly legal. If it's not legal, then you have her dead to rights on the light.
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