Light reflection, which is inherent to any object, often exhibits detrimental effects on solar energy conversion devices, and causes “light pollution” in our surroundings, affecting humans’ daily activities and the performance of various optical devices. It has been a great challenge to eliminate the reflections for ultra-wide wavebands. We propose an interface-fee region model and prove that ultra-broadband and extremely low reflectance is achievable both experimentally and theoretically. We demonstrate that extremely low reflectance was observed in surface modified Super-clear glass over a very wide range of wavelengths from 300 up to 2360 nm. A generic formula is proposed for the minimum thickness of the zero reflective layer in relation to the maximum wavelength.