Mechanical-electric composite-driven transfer nanoimprint for anti-reflective optical diffuser

Optical diffusers are the core component of optical information systems; however, the difficulty in reducing reflection caused by its complex surface morphology severely restricts the performance of the application systems. This study proposed and demonstrated a mechanical-electric composite-driven transfer nanoimprint technique to develop an anti-reflective optical diffuser by imprinting subwavelength-tapered nanocones on the extremely uneven micro-concave surface of a diffuser. Successively loading optimized mechanical pressure and electric-field on the designed discretely-supported template, enough deformation facing the uneven substrate was generated, which was impossible in the single-factor driven nanoimprinting technology. Therefore, full contact was formed between the template and the irregular diffused surface containing tightly narrow and deep micro-concave pits. To guarantee the high fidelity of the fabricated nanostructures, pre-curing and back-etching processes were implemented during transfer imprinting, which were different from the traditional process. Based on the full-contact mechanism and high fidelity process, an anti-reflective optical diffuser was developed through transfer imprinting of the sub-wavelength tapered nanocones on the surface of the diffuser. Experimental tests showed that the developed anti-reflective optical diffuser exhibited high spectral transmittance, high light intensity uniformity, and good durability.