Optical apparatus, projection optical system, exposure apparatus, and article manufacturing method

The invention relates to an optical apparatus, a projection optical system, an exposure apparatus, and an article manufacturing method. This optical device is provided with: a first concave mirror having a first reflecting surface; a second concave mirror disposed so as to be separated from the first concave mirror, the second concave mirror having a second reflecting surface; and a rectifying unit that guides the airflow flowing along the second reflecting surface of the second concave mirror to the first reflecting surface of the first concave mirror. 本发明涉及一种光学装置、投影光学系统、曝光装置和物品制造方法。光学装置具备：第1凹面反射镜，具有第1反射面；第2凹面反射镜，与前述第1凹面反射镜分离地配置，所述第2凹面反射镜具有第2反射面；以及整流部，将沿着前述第2凹面反射镜的前述第2反射面流动的前述气流向前述第1凹面反射镜的前述第1反射面引导。