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Studypool opse402 lab1 shg

Studypool opse402 lab1 shg

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Angle Dependency on Second Harmonic Generation of Light

Abstract.

The process of second harmonic generation from a high-power laser beam of light interacting

with a nonlinear crystal was experimented. The high-power laser beam of infrared light of

1064nm wavelength was directed through a nonlinear crystal which doubled the frequency of the

beam, transmitting a green wavelength of light of 532nm. It was determined that there were two

peaks of intensity for the second harmonic generation of light for the angle between the axis of

the nonlinear crystal and the polarization direction of the infrared laser. The intensity peaks were

about 180 degrees apart.

I. Introduction.

Linear optical processes describe systems where an electromagnetic wave comes in contact

with a linear material and will be transmitted or reflected at the same frequency as it started.

Examples of linear materials include simple mirrors, lenses, and diffraction gratings. Linear

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systems also follow the superposition principle which states that when waves in space overlap,

the resulting wave will be the sum of the two original waves. As the study of linear optics

progressed, the discovery of non-linear optics was made.

Nonlinear processes have been observed at low frequencies for the past hundred years,

such as in transformers and solenoids which contain iron [1]. However, it was not until the

1960’s, after the discovery and development of masers, and lasers that nonlinear processes were

proven to exist in optics [1]. The original display was performed by Peter Franken and his

coworkers in the Randall Laboratory at the University of Michigan. They used a quartz crystal

and a ruby laser for second harmonic generation of light following the nonlinear power series

equation describing the induced dipole on light [1]:

  









 













 

















where P is the induced dipole, E is the E-field, 



represent first order linear effects,





represents second order effects or second order optical susceptibility, which includes second

harmonic generation, and 



represents third order effects, or third order optical susceptibility

[1,2]. The 



portion of the formula showed to have an existing tensor element, determining the

results of the Franken and co-workers experiment as a nonlinear process in optics [1]. After the

discovery of non-linear optics, the subject has continued to advance and is now an essential part

to many optical instruments and processes, such as ultra-short pulsed lasers, optical signal

processing, and laser amplifiers [3].

After the discovery of second harmonic generation of light through by a nonlinear

medium lacking inversion symmetry, further studies and experimentation exponentially

expanded the knowledge of nonlinear optics. One particular scientist who greatly contributed to

applications of nonlinear optics using lasers is Nicolaas Bloembergen, who won the Nobel Prize

in Physics in 1981 for his research on the use of nonlinear optics in laser spectroscopy [4].

Bloembergen was able to effectively use the superposition principle of electromagnetic waves

through a nonlinear medium to create laser beams composed of waves with frequencies higher

and lower than those of visible light [4]. The discovery opened a wide range of laser

spectroscopy studies and applications, as lasers were never before able to emit beams in

wavelengths outside of the visible spectrum of light.

Section II of this report reviews the theory behind second harmonic generation, and section

III presents the experimental apparatus used in this experiment. Further, Section IV conveys the

results of the experiment and discusses these results, while section V presents the conclusion of

the experiment.

II. Theory

In traditional linear optics, the polarization in a system is linearly proportional to the

electric field that is placed on the material. However, in nonlinear optics and specifically

second harmonic generation of light, where coherent intensity occurs, the polarization of

light in a material can be expanded based on the electric field being applied to the material in

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Angle Dependency on Second Harmonic Generation of Light Abstract. The process of second harmonic generation from a high-power laser beam of light interacting with a nonlinear crystal was experimented. The high-power laser beam of infrared light of 1064nm wavelength was directed through a nonlinear crystal which doubled the frequency of the beam, transmitting a green wavelength of light of 532nm. It was determined that there were two peaks of intensity for the second harmonic generation of light for the angle between the axis of the nonlinear crystal and the polarization direction of the infrared laser. The intensity peaks were about 180 degrees apart. I. Introduction. Linear optical processes describe systems where an electromagnetic wave comes in contact with a linear material and will be transmitted or reflected at the same frequency as it started. Examples of linear materials include simple mirrors, lenses, and diffraction gratings. Linear systems also follow the superposition principle which states that when waves in space overlap, the resulting wave will be the sum of the two original waves. As the study of linear optics progressed, the discovery of non-linear optics was made. Nonlinear processes have been observed at low frequencies for the past hundred years, such as in transformers and solenoids which contain iron [1]. However, it was not until the 1960’s, after the discovery and development of masers, and lasers that nonlinear processes were proven to exist in ...
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