Dispersive Sweatt Model for Broadband Lens Design with Metasurfaces

The Sweatt model has been extensively used to design optical systems containing diffractive optical elements (DOEs) because it captures the dispersive characteristics of DOEs. We introduce a new dispersive Sweatt model (DSM) that can describe meta-atom (MA) dispersion, which has material and geometr...

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Main Authors: Weiyu Chen, Ko-Han Shih, C. Kyle Renshaw
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Photonics
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Online Access:https://www.mdpi.com/2304-6732/12/1/43
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author Weiyu Chen
Ko-Han Shih
C. Kyle Renshaw
author_facet Weiyu Chen
Ko-Han Shih
C. Kyle Renshaw
author_sort Weiyu Chen
collection DOAJ
description The Sweatt model has been extensively used to design optical systems containing diffractive optical elements (DOEs) because it captures the dispersive characteristics of DOEs. We introduce a new dispersive Sweatt model (DSM) that can describe meta-atom (MA) dispersion, which has material and geometric contributions in addition to diffraction. It uses a wavelength-dependent scalar coefficient to modify the diffractive dispersion and describe the dispersion of a given MA basis. This provides a robust framework to design systems containing metasurface (MS) elements while including their unique dispersive properties in the design optimization. Importantly, the DSM is based on ray optics and enables the design of MS-containing systems using conventional optical design software such as Zemax and Code V. We use the DSM to demonstrate the design of a hybrid refractive/MS achromatic doublet for the midwave infrared (MWIR) band. The design example includes multiple wavelengths and field angles during optimization and demonstrates excellent agreement between the DSM and real hybrid lens performance modeled using wave optics. We discuss the limits of the DSM and present a simple model to predict performance limits due to phase mismatch at Fresnel zone boundaries.
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spelling doaj-art-eec99738532e48bd9270959cebdbe1642025-01-24T13:46:18ZengMDPI AGPhotonics2304-67322025-01-011214310.3390/photonics12010043Dispersive Sweatt Model for Broadband Lens Design with MetasurfacesWeiyu Chen0Ko-Han Shih1C. Kyle Renshaw2College of Optics and Photonics, CREOL, University of Central Florida, Orlando, FL 32816, USACollege of Optics and Photonics, CREOL, University of Central Florida, Orlando, FL 32816, USACollege of Optics and Photonics, CREOL, University of Central Florida, Orlando, FL 32816, USAThe Sweatt model has been extensively used to design optical systems containing diffractive optical elements (DOEs) because it captures the dispersive characteristics of DOEs. We introduce a new dispersive Sweatt model (DSM) that can describe meta-atom (MA) dispersion, which has material and geometric contributions in addition to diffraction. It uses a wavelength-dependent scalar coefficient to modify the diffractive dispersion and describe the dispersion of a given MA basis. This provides a robust framework to design systems containing metasurface (MS) elements while including their unique dispersive properties in the design optimization. Importantly, the DSM is based on ray optics and enables the design of MS-containing systems using conventional optical design software such as Zemax and Code V. We use the DSM to demonstrate the design of a hybrid refractive/MS achromatic doublet for the midwave infrared (MWIR) band. The design example includes multiple wavelengths and field angles during optimization and demonstrates excellent agreement between the DSM and real hybrid lens performance modeled using wave optics. We discuss the limits of the DSM and present a simple model to predict performance limits due to phase mismatch at Fresnel zone boundaries.https://www.mdpi.com/2304-6732/12/1/43metalenshybrid lens systembroadband designSweatt modelphase dispersion
spellingShingle Weiyu Chen
Ko-Han Shih
C. Kyle Renshaw
Dispersive Sweatt Model for Broadband Lens Design with Metasurfaces
Photonics
metalens
hybrid lens system
broadband design
Sweatt model
phase dispersion
title Dispersive Sweatt Model for Broadband Lens Design with Metasurfaces
title_full Dispersive Sweatt Model for Broadband Lens Design with Metasurfaces
title_fullStr Dispersive Sweatt Model for Broadband Lens Design with Metasurfaces
title_full_unstemmed Dispersive Sweatt Model for Broadband Lens Design with Metasurfaces
title_short Dispersive Sweatt Model for Broadband Lens Design with Metasurfaces
title_sort dispersive sweatt model for broadband lens design with metasurfaces
topic metalens
hybrid lens system
broadband design
Sweatt model
phase dispersion
url https://www.mdpi.com/2304-6732/12/1/43
work_keys_str_mv AT weiyuchen dispersivesweattmodelforbroadbandlensdesignwithmetasurfaces
AT kohanshih dispersivesweattmodelforbroadbandlensdesignwithmetasurfaces
AT ckylerenshaw dispersivesweattmodelforbroadbandlensdesignwithmetasurfaces