Fig. 15: Strategies for zoom metalenses.
From: Dielectric metalens for miniaturized imaging systems: progress and challenges
a Variable focal length via microelectromechanical systems. Reproduced with permission130. Copyright 2021, American Chemical Society. b Continuous tuning of the focal length by stretching elastomeric materials. Reproduced with permission135. Copyright 2018, The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. c Doublet metalens offering dual-step zoom switched by the linear polarization state of the incident light. Reproduced with permission136. Copyright 2019, Optical Society of America. d Singlet metalens with dual focal lengths switched by the circular polarization state of the incident light. Reproduced with permission138. Copyright 2019, Optical Society of America. e Dual-step zoom based on phase transformation of optical change material. Reproduced with permission146. Copyright 2019, The Authors, published by Springer Nature. f Varifocal metalens based on tunable birefringent liquid crystals. Reproduced with permission148. Copyright 2021, American Chemical Society
