Highly damage resistant, broadband, hard antireflection coating for high power lasers in the ultraviolet to near‐infrared wavelength regions

Mechanically hard and broadband gradient refractive index antireflection coating was developed. It has a high damage threshold of ≳6 J/cm2 at 355 nm and 12–13 J/cm2 in the visible to near‐infrared region. It will be applicable to high power pulsed lasers as well as to industrial uses.