Reflectionless and invisible potentials in photonic lattices.

Area of Science:

• Photonics
• Optical physics
• Condensed matter physics

Background:

• Light propagation in optical media is typically governed by wave equations.
• Continuous optical media exhibit predictable scattering phenomena.
• Discrete photonic lattices offer unique light-matter interaction properties.

Purpose of the Study:

• To investigate the behavior of optical potentials in discrete photonic lattices.
• To explore the conditions under which an optical potential becomes reflectionless.
• To examine the implications of discrete translational symmetry on light scattering.

Main Methods:

• Theoretical analysis of optical potentials on discrete photonic lattices.
• Investigating the effect of transverse drift speed exceeding the light cone speed.
• Considering non-Hermitian optical potentials of the Kramers-Kronig type.

Main Results:

• An arbitrarily shaped optical potential becomes reflectionless when drifting faster than the lattice band's light cone speed.
• This reflectionless property is unique to discrete photonic systems and lacks counterparts in continuous media.
• A drifting non-Hermitian Kramers-Kronig potential acts as an invisible potential, allowing undistorted beam propagation.

Conclusions:

• Discrete translational symmetry in photonic lattices enables novel optical phenomena like reflectionless potentials.
• The concept of an 'invisible potential' is demonstrated for discrete optical beams.
• Findings suggest new possibilities for controlling light propagation in engineered photonic structures.