Noncollinear second-harmonic generation in sub-micrometer-poled RbTiOPO(4).

Area of Science:

• Nonlinear optics
• Materials science

Background:

• Quasi-phase-matched (QPM) nonlinear frequency conversion is crucial for laser technology.
• Fabrication of periodically poled materials with short periods is challenging.

Purpose of the Study:

• To investigate nonlinear frequency conversion in a crystal poled by the high-voltage atomic force microscope (HV-AFM) method.
• To demonstrate the capability of HV-AFM for creating structures suitable for QPM.

Main Methods:

• Fabrication of a periodically poled RbTiOPO4 crystal using HV-AFM with a short poling period (1.18 microm).
• Experimental setup for generating noncollinear second harmonic generation (SHG).
• Optical characterization of the poled area homogeneity.

Main Results:

• Successful generation of noncollinear quasi-phase-matched second harmonic waves.
• Observation of SHG at large angles relative to the fundamental wave due to the short poling period.
• Measurements showed reasonable agreement with analytical calculations.

Conclusions:

• HV-AFM is a viable technique for fabricating nonlinear optical crystals with short poling periods.
• The generated noncollinear SHG demonstrates the potential for novel optical applications.
• The study provides a foundation for future research in HV-AFM-based nonlinear optics.