Pretty sure this is the short story "Window" by Bob Leman. It was adapted into an episode of the short-lived anthology series "Night Visions" as "A View Through The Window."
Description courtesy of this review:
I just re-read the short story “Window” by Bob Leman. It first appeared in The Magazine of Fantasy and Science Fiction in the May 1980 issue.
The big problem in the story is caused by an army researcher who is looking into ESP and the effect that specific words have on the environment and on the minds of others… put another way? Magic spells. We don’t see any of the details of this research in the story, just the aftermath of what I’m calling an accident.
In Leman’s story, the result of the accident is the appearance of a window on the past. At least it appears that it is the past. It looks peaceful, pastoral, and it’s alluring. Characters in the story are strongly attracted to both the setting and the family they see through this window. Then Reeves takes an opportunity (dare I say “a five-second ‘window’ of opportunity?”) and leaps to the other side, where he finds things not as they seem. Teeth are bared, Reeves is shredded, and in that terrible instant the truth of the thing is revealed. It’s not the past at all, it’s Somewhere Else. And evil lives there. And that evil now knows we exist and are tasty.
You can watch the adaptation at:
And if you want to see what publications the story was printed in, here's the ISFDB page.