I used to have one of these at another house in the laundry room. Cats could jump over it to get to their "box" and food, dogs stayed out. ;-) Dutch Door + Glass Top (ours wasn't glass, but I love Dutch doors)
Perfect for cellar stairs where a full door isn't possible or even for split level style home. This will keep pets and children upstairs! We bought a used door at a salvage yard, cut it in half and framed it in and voila! Perfect solution! The hinged metal plate drops down to fill the gap from the stair tread to the door.