Tunable coherent microwave beam splitter and combiner at the single-photon level

Y Y.-H. Huang (Department of Physics, National Tsing Hua University 1 , Hsinchu 30013,) K K.-M. Hsieh (Department of Physics, City University of Hong Kong 2 , Kowloon, Hong Kong SAR 999077,) F F. Aziz (Department of Physics, National Tsing Hua University 1 , Hsinchu 30013,) Z Z. Q. Niu (State Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences 3 , Shanghai 200050,) P P. Y. Wen (Department of Physics, National Chung Cheng University 5 , Chiayi 621301,) Y Y.-T. Cheng (Department of Physics, City University of Hong Kong 2 , Kowloon, Hong Kong SAR 999077,) Y Y.-S. Tsai (Department of Physics, National Tsing Hua University 1 , Hsinchu 30013,) J J. C. Chen X Xin Wang A A. F. Kockum (Department of Microtechnology and Nanoscience, Chalmers University of Technology 7 , 412 96 Gothenburg,) Z Z.-R. Lin (State Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences 3 , Shanghai 200050,) Y Y.-H. Lin (Department of Physics, National Tsing Hua University 1 , Hsinchu 30013,) I I.-C. Hoi (Department of Physics, National Tsing Hua University 1 , Hsinchu 30013,)

Abstract

A beam splitter is a key component used to direct and combine light paths in various optical and microwave systems. It plays a crucial role in devices like interferometers, such as the Mach–Zehnder and Hong–Ou–Mandel setups, where it splits light into different paths for interference measurements. These measurements are vital for precise phase and coherence testing in both classical and quantum optical experiments. In this work, we present a nonlinear beam splitter and beam combiner utilizing a frequency-tunable superconducting artificial atom in a one-dimensional open waveguide. Probed with coherent states at the single-photon level (average photon number ⟨N⟩ ≪1), this device demonstrates highly tunable transparency, ranging from near unity to complete reflection. Additionally, the beam combiner can merge two coherent beams, generating interference fringes as the relative phase between them varies.

Article Details

Volume / Issue Vol. 127, Issue 1
Published July 07, 2025
ISSN 0003-6951
Publisher American Institute of Physics

Journal Info

Applied Physics Letters

American Institute of Physics

ISSN: 0003-6951 Physical Sciences

Authors (13)

Y

Y.-H. Huang

Department of Physics, National Tsing Hua University 1 , Hsinchu 30013,

K

K.-M. Hsieh

Department of Physics, City University of Hong Kong 2 , Kowloon, Hong Kong SAR 999077,

F

F. Aziz

Department of Physics, National Tsing Hua University 1 , Hsinchu 30013,

Z

Z. Q. Niu

State Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences 3 , Shanghai 200050,

P

P. Y. Wen

Department of Physics, National Chung Cheng University 5 , Chiayi 621301,

Y

Y.-T. Cheng

Department of Physics, City University of Hong Kong 2 , Kowloon, Hong Kong SAR 999077,

Y

Y.-S. Tsai

Department of Physics, National Tsing Hua University 1 , Hsinchu 30013,

J

J. C. Chen

X

Xin Wang

A

A. F. Kockum

Department of Microtechnology and Nanoscience, Chalmers University of Technology 7 , 412 96 Gothenburg,

Z

Z.-R. Lin

State Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences 3 , Shanghai 200050,

Y

Y.-H. Lin

Department of Physics, National Tsing Hua University 1 , Hsinchu 30013,

I

I.-C. Hoi

Department of Physics, National Tsing Hua University 1 , Hsinchu 30013,