Epsilon-near-zero regime for ultrafast opto-spintronics.

Area of Science:

• Condensed Matter Physics
• Non-linear Optics
• Materials Science

Background:

• Non-linear phononics utilizes high-amplitude lattice vibrations excited by infrared pulses to control material properties.
• Conventional methods rely on exciting transverse optical phonon modes, maximizing the imaginary part of permittivity.
• The epsilon-near-zero (ENZ) regime, where the real part of permittivity is zero, is known for strong light-matter interactions.

Purpose of the Study:

• To explore an alternative strategy in non-linear phononics using the ENZ regime.
• To investigate the potential of tailoring light pulses to the ENZ frequency in dielectric crystals.
• To highlight future research directions and opportunities in phononic ENZ physics.

Main Methods:

• Theoretical perspective on light-matter interaction in the phononic ENZ regime.
• Analysis of dielectric crystals in the infrared spectral range where ENZ naturally occurs.
• Focus on resonant excitation of lattice vibrations at the ENZ frequency.

Main Results:

• Strong enhancement of light-matter interaction in the phononic ENZ regime.
• Demonstration of the possibility of permanently switching spin and polarization order parameters.
• Identification of ENZ as a fertile, yet under-explored, area for phononic control.

Conclusions:

• The phononic ENZ regime offers a powerful new pathway for controlling material properties.
• This approach provides unprecedented control, including permanent switching of spin and polarization.
• Further research into phononic ENZ is crucial for unlocking novel applications in optics and materials science.