A single-lens universal interferometer: Towards a class of frugal optical devices

TL;DR

This paper introduces a novel single-lens interferometer, the iLens, enabling ultra-precise, compact, and affordable optical measurements on various surfaces with real-time sub-20 picometer resolution, expanding applications in sensing and imaging.

Contribution

The work presents a new integrated optical element, the iLens, that simplifies interferometry, achieving high stability and sensitivity in a miniaturized, cost-effective device for diverse practical applications.

Findings

Achieved sub-20 picometer real-time precision with simple intensity detection.

Developed a paper-based optical pico-balance with 1000 times higher sensitivity than traditional balances.

Constructed broadband acoustic sensors with matched or higher sensitivity than conventional piezo and electromagnetic sensors.

Abstract

The application of precision interferometers is generally restricted to expensive and smooth high-quality surfaces. Here, we offer a route to ultimate miniaturization of interferometer by integrating beam splitter, reference mirror and light collector into a single optical element, an interference lens (iLens), which produces stable high-contrast fringes from in situ surface of paper, wood, plastic, rubber, unpolished metal, human skin, etc. A self-referencing real-time precision of sub-20 picometer (~ lambda/30000) is demonstrated with simple intensity detection under ambient conditions. The principle of iLens interferometry has been exploited to build a variety of compact devices, such as a paper-based optical pico-balance, having 1000 times higher sensitivity and speed, when compared with a high-end seven-digit electronic balance. Furthermore, we used cloth, paper, polymer-films to readily construct broadband acoustic sensors possessing matched or higher sensitivity when compared with piezo and electromagnetic sensors. Our work opens path for affordable yet ultra-precise frugal photonic devices and universal micro-interferometers for imaging.