“And Voldemort never knew about the Hallows?”
“I do not think so, because he did not recognize the Resurrection Stone he turned into a Horcrux. But even if he had known about them, Harry, I doubt that he would have been interested in any except the first. He would not think that he needed the Cloak, and as for the stone, whom would he want to bring back from the dead? He fears the dead. He does not love.”
Harry Potter and the Deathly Hallows, Chapter 35: King's Cross
Dumbledore suspects that Voldemort did not know of the Hallows (especially since he was raised by muggles and wouldn't have heard the children story) and that even if he did, he obviously did not care about them, since he had in his possession the Resurrection Stone, and didn't appear to know.
The Elder Wand, on the other hand, was not known exclusively for being a Hallow, as Hermione knew the existence of powerful wands, but not of the Hallows.
“The Deathstick, the Wand of Destiny, they crop up under different names through the centuries, usually in the possession of some Dark wizard who’s boasting about them. Professor Binns mentioned some of them, but oh, it’s all nonsense. Wands are only as powerful as the wizards who use them. Some wizards just like to boast that theirs are bigger and better than other people’s.”
“But how do you know,” said Harry, “that those wands — the Deathstick and the Wand of Destiny — aren’t the same wand, surfacing over the centuries under different names?”
Harry Potter and the Deathly Hallows, Chapter 21: The Tale of the Three Brothers
It's key to note that, while the above established that Voldemort most likely did not know that the cloak was a Hallow as Nkrisc's quote shows, he definitely KNEW Harry HAD a cloak.
