Strain
engineering on the dispersion property and anisotropy of
second-harmonic generation (SHG) is crucial for advancing the understanding
and development of nonlinear optical materials and devices with tailored
light-matter interactions. Herein, we theoretically demonstrate the
intricate relationship between strain engineering and modulation of
SHG in ferroic monolayer GeSe. The bandgap tends to expand upon the
application of strain, be it uniaxial or biaxial in nature. It is
important to note that neither uniaxial nor biaxial strains induce
the emergence of novel nonzero second-order nonlinear optical susceptibility
elements; they do exert a significant influence on the pre-existing
elements. This alteration has a consequential effect on the SHG process.
Additionally, the characteristic peak of the second-order nonlinear
coefficient element d11 undergoes a significant
shift with the increase in strain, attributed to the variation in
interband transition contributions induced by strain. The imposition
of strain, whether uniaxial or biaxial, can markedly alter the dispersion
and anisotropic properties of the nonlinear optical response. These
modifications are observed to be contingent upon factors such as the
wavelength, azimuthal angle, polarization angle, and incidence angle.
These findings provide valuable insights into the design and optimization
of 2D materials for optoelectronic applications, highlighting the
potential of strain engineering as a powerful tool for tailoring nonlinear
optical properties.