Roller nanoimprint lithography for low-cost nanoscale random lattice diffractive optical elements

Man Zhang,Liang-Ping Xia,Li-Fang Shi,A-Xiu Cao,Sui-Hu Dang,Chun-Lei Du

doi:10.1063/1.5137755

Abstract

In this paper, effective fabrication of high-resolution diffractive optical elements on a polymer substrate is demonstrated using roller nanoimprint lithography. A nanoscale diffraction grating mold, which can generate a random laser pattern, is fabricated by scan-and-repeat projection lithography. The mold is imprinted to a thin polymer on the soft substrate via roller nanoimprint lithography, which has high efficiency, high fidelity, and high throughput for mass production. This fabrication process can produce high-resolution nanostructures while reducing the cost substantially. We obtained large-area polymer diffractive optical elements with a flexible substrate, which can generate high-quality diffraction random lattice patterns with sub-250 nm resolution for an 808-nm wavelength laser. The diffractive optical elements have about 83.2% diffraction efficiency and 99.7% uniformity of random pattern intensity. It is believed that this fabrication technique can promote practical applications of diffractive optical elements, such as laser wavefront correction, face and activity recognition, and optical communication.

Highlights

The mold is imprinted to a thin polymer on the soft substrate via roller nanoimprint lithography, which has high efficiency, high fidelity, and high throughput for mass production
Diffractive optical elements (DOEs) are thin sheet wavefront processors used to shape the distribution of an incident laser beam with known properties into a specified pattern,1–6 which perceptibly minimize the use of optical systems
Scan-and-repeat projection lithography is used to prepare the DOE stamp with nanoscale resolution

Summary

INTRODUCTION

Diffractive optical elements (DOEs) are thin sheet wavefront processors used to shape the distribution of an incident laser beam with known properties into a specified pattern, which perceptibly minimize the use of optical systems. As a special replication technique, nanoimprint lithography (NIL) has been studied to implement a low-cost, high-throughput, and highresolution application.. We proposed a novel roller nanoimprint lithography technique to fabricate low-cost nanoscale DOEs in high throughput and produced in a large volume. The imprinting roller is pressed on the flexible substrate to ensure the stamp compact is in contact with the roller by rolling and applying uniform pressure. This novel method is used to fabricate polymer DOEs on a flexible substrate with low cost and high throughput. This study can promote DOE devices in practical applications like laser beam shaping, image recognition, wavefront correction, optical interconnection, and optical communication

FABRICATION PROCESS

CHARACTERIZATION

RESULTS AND DISCUSSIONS

CONCLUSION