Accurate measurement of the photonic crystal slab period using diffraction in the Littrow configuration

Published

October 25, 2021

Author(s)

John R. Lawall, Yiliang Bao, Jason Gorman

Abstract

Photonic crystal slab devices with subwavelength periods can be tailored to provide a remarkable range of functionalities, such as ultrahigh reflectivity in a structure only 200nm in thickness. Accurate measurement of the characteristics of these structures is essential to compare their performance to theoretical expectations, and to better understand the origin of unexpected behavior. Conventional measurements using scanning electron microscopy are limited at the level of tens of nanometers due to calibration issues and image distortion, and furthermore risk contaminating the sample by hydrocarbon deposition. In this work, we present a simple non-invasive method employing diffraction of a visible wavelength reference in Littrow configuration for measuring the period of a photonic crystal slab. We have measured periods of our devices with uncertainty below0.5nm, and expect that the uncertainty could be improved by an order of magnitude simply by use of a better rotation stage. In addition to facilitating device development, our approach can be used to explore possible variations in the period of the photonic crystal due to its operating environment and aging.

Citation

Optics Express

Volume

29

Issue

23

Pub Type

Journals

Download Paper

https://doi.org/10.1364/OE.438308

Local Download

Keywords

Photonic crystal, Littrow configuration, diffraction

Citation

Lawall, J. , Bao, Y. and Gorman, J. (2021), Accurate measurement of the photonic crystal slab period using diffraction in the Littrow configuration, Optics Express, [online], https://doi.org/10.1364/OE.438308, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=932107 (Accessed October 17, 2025)