Spatial mode control of radiation generated by frequency difference in periodically poled crystals

Area of Science:

• Nonlinear optics
• Laser physics
• Materials science

Background:

• Continuous-wave (CW) infrared laser beams are essential tools in various scientific fields.
• Controlling the spatial properties of laser beams, such as their mode, is critical for advanced applications.
• Difference frequency generation (DFG) in nonlinear crystals is a common method for producing tunable infrared radiation.

Purpose of the Study:

• To demonstrate the control over the spatial mode of a narrow-linewidth, CW infrared radiation beam.
• To investigate the generation of specific beam profiles, such as hollow beams.
• To validate experimental findings with a numerical model.

Main Methods:

• Utilizing difference frequency generation (DFG) in a periodically poled crystal.
• Adjusting key experimental parameters to influence the generated beam's spatial mode.
• Developing and employing a numerical routine for simulation and comparison.

Main Results:

• Successful control of the spatial mode of the generated infrared beam was achieved.
• Demonstrated the capability to generate hollow beams by manipulating experimental parameters.
• Experimental results showed excellent agreement with the developed numerical routine without free parameters.

Conclusions:

• The spatial mode of DFG-generated infrared beams can be effectively controlled.
• The generation of hollow beams is feasible through parameter tuning.
• The validated numerical model provides a predictive tool for beam shaping in nonlinear optical systems.
• These findings have significant implications for high-resolution spectroscopy and atom manipulation techniques.