Vortex-based all-optical manipulation of stored light at low light levels

Area of Science:

• Quantum optics
• Atomic physics
• Nonlinear optics

Background:

• Electromagnetically induced transparency (EIT) offers unique light-matter interactions.
• Giant cross-Kerr nonlinearity in EIT systems enables low-light manipulation.
• Vortex beams carry orbital angular momentum, crucial for advanced optical applications.

Purpose of the Study:

• To implement vortex-based multimode manipulation of stored light at low light levels.
• To imprint phase-only modulation onto stored light using image-bearing signal fields.
• To investigate the generation and control of vortex modes in retrieved light fields.

Main Methods:

• Exploiting the giant cross-Kerr nonlinearity of an EIT system in ultracold atoms.
• Using image-bearing signal light fields with angular intensity profiles to imprint gratings.
• Numerical investigation of Fraunhofer diffraction patterns and spiral spectra of retrieved probe fields.

Main Results:

• Azimuthal imprinting of sinusoidal grating structures on stored probe light with negligible nonlinear absorption loss.
• Generation of collinearly superimposed vortex modes in the far field upon probe light retrieval.
• Efficient control of diffracted vortex modes by tuning weak signal fields, considering finite atomic gas size.

Conclusions:

• Demonstration of a fundamental diffraction phenomenon with angular gratings in an EIT system.
• Provides a novel method for all-optical multidimensional quantum information processing of stored light.
• Highlights the potential of ultracold atom EIT systems for advanced optical control and quantum technologies.