The victim, a resident of Haryana, was a first-year student of Delhi University, they said.
She alleged that the professor would try to touch her inappropriately whenever he found her alone. He would follow her and used to call her to meet him alone, the police said.
When she opposed his advances, he threatened to fail her in internal exams, they said.
An FIR was registered in the matter on January 31 and further probe is underway, the police said.