What is third order nonlinear optical properties?

It occurs whenever the strong field of a laser beam propagates in a third-order nonlinear medium whose refractive index depends on the beam intensity. The real part of the third-order susceptibility results in a change in the index of refraction of the material [7].

What is third order nonlinear susceptibility?

THG is a coherent process in which one measures the purely electronic origin third-order nonlinear optical susceptibility χ (3) (−3ω; ω,ω,ω). As the harmonic wave has to follow the fundamental one, the response time is equal to the oscillation period, i.e., around 10−15 s.

What is non linear refractive index?

nonlinear index of refraction (n2) When an intense laser beam passes through a material, the electric field of the beam can induce a change in the refractive index of the material that is proportional to the intensity of the beam. This nonlinear effect is called the Kerr effect.

What is nonlinear optical susceptibility?

Nonlinear optical susceptibilities are characteristic constants of a medium, and are determined by the microscopic structure of the medium. From: Encyclopedia of Materials: Science and Technology, 2001.

What is a third order process?

The term “third order nonlinear optical (NLO) materials” refers to materials whose polarization depends on the intensity of an applied electromagnetic field. This intensity dependence gives rise to a variety of useful properties such as self-focusing, two-photon absorption, and third harmonic generation.

How do you calculate non linear refractive index?

Now the nonlinear refractive index n2 can be calculated from the nonlinear susceptibility by n2 = (12π/n0) χ 1111 ( 3 ) (–ω; ω, ω, –ω), were n0 is the linear refractive index of the material. It is clear that the measurement of n2 rigorously requires ωa = ωb = ωc.

What is the 3rd harmonic frequency?

1. The 180-Hz sinusoid is called the third harmonic, since its frequency is three times that of the fundamental frequency.

What is the third harmonic?

The lowest possible frequency at which a string could vibrate to form a standing wave pattern is known as the fundamental frequency or the first harmonic. The second lowest frequency at which a string could vibrate is known as the second harmonic; the third lowest frequency is known as the third harmonic; and so on.

What is non-linear optical crystal?

Nonlinear optical (NLO) crystals serves the goal for generating coherent laser in the ultraviolet (UV) and deep-ultraviolet (DUV) frequency range through second-harmonic generation (SHG). Noncentrosymmetricity is the criterion for the SHG to be allowed in the material.