Abstract

As an important theoretical concept, temporal boundaries provide researchers with new insights for tailoring electromagnetic waves in the time domain. Because a temporal boundary breaks the time translation symmetry, a source is necessary to satisfy energy conservation. In this Letter, we quantify the relationship between refractive index contrast and the required energy exchange. More specifically, to realize a temporal boundary with a large refractive index contrast, a correspondingly large and abrupt energy exchange is required. Considering this practical difficulty, we propose to mimic a large-contrast temporal boundary by staggering a series of small-contrast temporal boundaries separated by carefully designed durations. In this way, the process of energy input/output is distributed over an elongated duration, but their effect can still be cumulative. This process is analogous to a multi-resonant system with a periodic energy input. Based on this design principle, we discuss several scenarios for different temporal profiles of refractive index and their corresponding energy requirements.

© 2022 Optica Publishing Group

Energy conservation at an optical temporal boundary

K. B. Tan, H. M. Lu, and W. C. Zuo
Opt. Lett. 45(23) 6366-6369 (2020)

Analytical transient analysis of temporal boundary value problems using the d’Alembert formula

Wending Mai and Douglas H. Werner
Opt. Lett. 46(22) 5727-5730 (2021)

Dual-output kilohertz pump laser for high-energy picosecond OPCPA

Jakub Novák, Emily C. Erdman, Roman Antipenkov, Boguslaw Tykalewicz, Martin Horáček, Petr Mazůrek, Murat Torun, Jonathan T. Green, Jack A. Naylon, Pavel Bakule, and Bedřich Rus
Opt. Lett. 47(19) 4869-4872 (2022)

Highly sensitive multi-stage terahertz parametric upconversion detection based on a KTiOPO₄ crystal

Yuye Wang, Changhao Hu, Chao Yan, Kai Chen, Yuma Takida, Hiroaki Minamide, Degang Xu, and Jianquan Yao
Opt. Lett. 47(22) 5853-5856 (2022)

Projected refractive index framework for multi-wavelength phase retrieval

Yunhui Gao and Liangcai Cao
Opt. Lett. 47(22) 5965-5968 (2022)