Twisted elliptical multi-Gaussian Schell-model beams and their propagation properties.

Area of Science:

• Optics and Photonics
• Laser Physics
• Beam Propagation

Background:

• Partially coherent light sources are crucial in various optical applications.
• Gaussian Schell-model beams are widely studied, but extensions are needed for novel beam profiles.
• Controlling beam characteristics like profile shape and angular momentum is an active research area.

Purpose of the Study:

• To introduce and characterize a novel partially coherent light source: twisted elliptical multi-Gaussian Schell-model (TEMGSM) beams.
• To derive analytical expressions for the cross-spectral density (CSD) of TEMGSM beams propagating through paraxial optical systems.
• To investigate the generation of specific beam profiles and the rotational dynamics of these beams.

Main Methods:

• Formulating the cross-spectral density (CSD) function as an incoherent superposition of elliptical twisted Gaussian Schell-model sources.
• Utilizing the generalized Collins formula for analyzing beam propagation through paraxial ABCD optical systems.
• Employing the Wigner distribution function to derive analytical expressions for orbital angular momentum (OAM) and propagation factor.

Main Results:

• TEMGSM beams can produce flat-topped elliptical beam profiles in the far field.
• The beam spot exhibits controllable clockwise or anti-clockwise rotation during propagation.
• Analytical expressions for OAM and propagation factor were derived, showing dependence on twisted factor and beam index.

Conclusions:

• TEMGSM beams offer a versatile new class of partially coherent sources with unique propagation characteristics.
• The ability to control beam profile shape and rotation has implications for optical manipulation and communication.
• Further research can explore applications of TEMGSM beams in areas requiring tailored light fields.