The technique for preparing a linear rectangular arch microlens array with 20 elements on quartz substrate using Ar ion beam etching has been investigated. The optical performance of the microlens array has been measured. The microlens array was mounted onto a linear YBa 2Cu 3O 7-δ high T c superconducting thin film IR detector. The experimental results show that the optical response performance with hybird structure of microlens and IR detector array can be remarkably improved.