Abstract
Abstract Optical displacement metrology is important in nanotechnology and used to identify positions and displacements of nanodevices. Although several methods have been proposed, a sensor with ultracompact size, angstrom-scale resolution, and large measurement range is still lacking. We propose an optical displacement sensor with wavelength modulation that can demonstrate subwavelength footprint and angstrom-level resolution with large measurement range in this study. The proposed sensor consists of two optical slot antennas. Surface plasmon polaritons (SPPs) are launched at antennas and interfere when a tightly focused broadband light source illuminates the sensor. Spectrum of output SPPs presents a dip, which depends on the position of focal spot of incident light and is used to extract displacement. A maximum resolution of 0.734 nm was obtained. Furthermore, we used interference fringe of two broadband beams as light source and the measurement range of the sensor is not limited by the size of the tightly focused light source while maintaining high resolution. The method utilizes a new mechanism of wavelength modulation to overcome the trade-off between the high resolution and large measurement range, and achieve a variety of potential applications for nanometrology in the future.
Highlights
Integration of nanodevices in nanotechnology and manufacturing has progressed considerably in recent years [1]
We propose a wavelength modulation sensing technique based on asymmetric plasmonic antenna pairs in this work to realize displacement sensors with characteristics of subwavelength dimensions, angstrom-level resolution, and large measurement range
The sensor fabricated in an Au film with a thickness of h on a silica substrate is composed of two slot antennas with the same width (w) and different lengths (L1 and L2)
Summary
Integration of nanodevices in nanotechnology and manufacturing has progressed considerably in recent years [1]. The ability of optical metrology to measure displacement in a noncontact manner is an important advantage [2]. The limited practical application of optical metrology due to large footprints fails to meet the demand of large-scale integration. Surface plasmon polaritons (SPPs) originate from collective oscillations of conductive carriers and present the unique optical characterization of subwavelength confinement [13,14,15,16,17]. This property allows the use of metallic nanostructures in optical sensors for dimension minimization. The nanosensor resolution was 3.3 nm in the deterministic measurement when high-order Hermite–
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
