Search the library catalog for specific authors, or just use "poetry" as one of your keywords along with a topic, like "nature and poetry."
You can browse current literary journals on the 3rd floor, near Starbucks. Here are a few to look for, with call numbers:
Paris Review - AP4.P245
Kenyon Review - AP2. K426
North American Review - AP2. N7
Epoch - AP2. E68
Chicago Review - AP2. C5152
Tin House - PN 6010.5 T56
Parnassus: Poetry Review - PN 6099.6 P36
Beloit Poetry Journal - PS 301.43
Bat City Review - PS 536.2 B299
American Poetry Review - PS 581. A44
Poetry - PS 580. P63
An excellent way to find poems from a variety of authors/eras that you might not have come across otherwise. Search for more through the catalog.