Demonstration of a large-scale optical exceptional point structure.

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Exceptional points (EPs) are critical points in parameter space where eigenvalues and eigenvectors coalesce.
• Optical EPs offer unique light manipulation capabilities, including unidirectional reflectionless propagation and enhanced sensing.

Purpose of the Study:

• To demonstrate a large-scale (4-inch) optical exceptional point structure operating at visible frequencies.
• To experimentally validate the abrupt phase transition associated with crossing an EP in wavelength.
• To explore the potential of wafer-scale EP devices for free-space optics.

Main Methods:

• Fabrication of a multilayer dielectric structure comprising absorbing and non-absorbing materials.
• Optical characterization to verify unidirectional reflectionless light transport.
• Theoretical analysis and experimental measurement of phase transitions around the EP.

Main Results:

• Successful implementation of a 4-inch optical exceptional point structure.
• Demonstration of wafer-scale unidirectional reflectionless light transport.
• Experimental confirmation of abrupt phase transitions at the EP in wavelength.

Conclusions:

• Large-scale optical EPs are achievable with multilayer dielectric designs.
• The demonstrated phase transition phenomenon is robust and experimentally verified.
• This work paves the way for practical applications of EPs in free-space optical systems.