Second-order Processes - Revision history

Cmditradmin at 16:10, 20 October 2016

2016-10-20T16:10:47Z

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	[http://depts.washington.edu/~~cmdwiki~~/media/NLO_materials.html Concept Map for Second Order Non linear Optics]		[http://depts.washington.edu/cmditr/media/NLO_materials.html Concept Map for Second Order Non linear Optics]

	Second order non linear optics involves the search for materials whose optical properties can be controlled with an applied electrical or optical field. They are second order because the effect is quadratic with respect to field strength. These extremely fast processes can be used for optical switching in telecommunication and the frequency effects can be used for specialized spectroscopy, imaging and scanning.		Second order non linear optics involves the search for materials whose optical properties can be controlled with an applied electrical or optical field. They are second order because the effect is quadratic with respect to field strength. These extremely fast processes can be used for optical switching in telecommunication and the frequency effects can be used for specialized spectroscopy, imaging and scanning.

Cmditradmin at 16:10, 20 October 2016

2016-10-20T16:10:02Z

← Older revision		Revision as of 09:10, 20 October 2016
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	</tr>		</tr>
	</table>		</table>
	[http://depts.washington.edu/~~cmditr~~/media/NLO_materials.html Concept Map for Second Order Non linear Optics]		[http://depts.washington.edu/cmdwiki/media/NLO_materials.html Concept Map for Second Order Non linear Optics]

	Second order non linear optics involves the search for materials whose optical properties can be controlled with an applied electrical or optical field. They are second order because the effect is quadratic with respect to field strength. These extremely fast processes can be used for optical switching in telecommunication and the frequency effects can be used for specialized spectroscopy, imaging and scanning.		Second order non linear optics involves the search for materials whose optical properties can be controlled with an applied electrical or optical field. They are second order because the effect is quadratic with respect to field strength. These extremely fast processes can be used for optical switching in telecommunication and the frequency effects can be used for specialized spectroscopy, imaging and scanning.

Cmditradmin at 22:36, 3 November 2011

2011-11-03T22:36:19Z

Show changes

Chrisb: /* Kerr and Pockels Effects */

2011-08-15T22:28:54Z

Kerr and Pockels Effects

← Older revision		Revision as of 15:28, 15 August 2011
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	'''S''' is the Kerr coefficient		'''S''' is the Kerr coefficient
	*S~ 10-18 – 10-14 mV in crystals		*S~ 10<sup>-18</sup> – 10<sup>-14</sup> mV in crystals
	*S~ 10-22 – 10-19 mV in liquids		*S~ 10<sup>-22</sup> – 10<sup>-19</sup> mV in liquids

	This is similar to the Pockels effect except that the refractive index varies parabolically or quadratically with the electric field.		This is similar to the Pockels effect except that the refractive index varies parabolically or quadratically with the electric field.

Chrisb: /* Frequency Doubling and Sum-Frequency Generation */

2011-08-12T23:34:13Z

Frequency Doubling and Sum-Frequency Generation

← Older revision		Revision as of 16:34, 12 August 2011
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	=== Frequency Doubling and Sum-Frequency Generation ===		=== Frequency Doubling and Sum-Frequency Generation ===

	One nonlinear optical phenomena is that when you shine light at one frequency on a material you get out light with twice the frequency. This process is known as second harmonic generation (SHG). SHG is a special type of sum frequency generation (SFG). SFG occurs when ω<sub>3</sub> = ω<sub>1</sub> + ω<sub>2</sub>. If ω<sub>3</sub> = ω<sub>1</sub> – ω<sub>2</sub>, this results in difference frequency generation (DFG). These processes are ~~used to generate different frequencies of light, and thus new wavelengths of light can be used~~ in ~~experiments~~.		One nonlinear optical phenomena is that when you shine light at one frequency on a material you get out light with twice the frequency. This process is known as second harmonic generation (SHG). SHG is a special type of sum frequency generation (SFG). SFG occurs when ω<sub>3</sub> = ω<sub>1</sub> + ω<sub>2</sub>. If ω<sub>3</sub> = ω<sub>1</sub> – ω<sub>2</sub>, this results in difference frequency generation (DFG). These processes are described in more detail below.

	The electronic charge displacement (polarization) induced by an oscillating electric field (e.g., light) can be viewed as a classical oscillating dipole that itself emits radiation at the oscillation frequency.		The electronic charge displacement (polarization) induced by an oscillating electric field (e.g., light) can be viewed as a classical oscillating dipole that itself emits radiation at the oscillation frequency.

Chrisb: /* Taylor Expansion with Oscillating Electric Fields-SHG */

2011-08-12T23:30:25Z

Taylor Expansion with Oscillating Electric Fields-SHG

← Older revision		Revision as of 16:30, 12 August 2011
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	Using a power series expansion :<math>Ecos^2(\omega t) E\,\!</math> can be substituted for E		Using a power series expansion :<math>Ecos^2(\omega t) E\,\!</math> can be substituted for E

	:<math>P = (P_0 + \chi^{(1)}E_0 cos(\omega t) + \chi^{(2)} E_0^2cos^2(\omega t) + \chi^{(3)} E_0^3 cos^3(\omega t) + ...\,\!</math>		:<math>P = P_0 + \chi^{(1)}E_0 cos(\omega t) + \chi^{(2)} E_0^2cos^2(\omega t) + \chi^{(3)} E_0^3 cos^3(\omega t) + ...\,\!</math>

	Where		Where

Chrisb: /* Frequency Doubling and Sum-Frequency Generation */

2011-08-12T23:25:26Z

Frequency Doubling and Sum-Frequency Generation

← Older revision		Revision as of 16:25, 12 August 2011
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	=== Frequency Doubling and Sum-Frequency Generation ===		=== Frequency Doubling and Sum-Frequency Generation ===

	One nonlinear optical phenomena is that when you shine light at one frequency on a material you get out light with twice the frequency. This process is known as second harmonic generation (SHG). SHG is a special type of sum frequency generation (SFG). SFG occurs when ω<sub>3</sub> = ω<sub>1</sub> ~~and~~ ω<sub>2</sub>. If ω<sub>3</sub> = ω<sub>1</sub> – ω<sub>2</sub>, this results in difference frequency generation (DFG). These processes are used to generate different frequencies of light, and thus new wavelengths of light can be used in experiments.		One nonlinear optical phenomena is that when you shine light at one frequency on a material you get out light with twice the frequency. This process is known as second harmonic generation (SHG). SHG is a special type of sum frequency generation (SFG). SFG occurs when ω<sub>3</sub> = ω<sub>1</sub> + ω<sub>2</sub>. If ω<sub>3</sub> = ω<sub>1</sub> – ω<sub>2</sub>, this results in difference frequency generation (DFG). These processes are used to generate different frequencies of light, and thus new wavelengths of light can be used in experiments.

	The electronic charge displacement (polarization) induced by an oscillating electric field (e.g., light) can be viewed as a classical oscillating dipole that itself emits radiation at the oscillation frequency.		The electronic charge displacement (polarization) induced by an oscillating electric field (e.g., light) can be viewed as a classical oscillating dipole that itself emits radiation at the oscillation frequency.

Chrisb: /* Frequency Doubling and Sum-Frequency Generation */

2011-08-12T23:25:02Z

Frequency Doubling and Sum-Frequency Generation

← Older revision		Revision as of 16:25, 12 August 2011
Line 159:		Line 159:
	=== Frequency Doubling and Sum-Frequency Generation ===		=== Frequency Doubling and Sum-Frequency Generation ===

	One nonlinear optical phenomena is that when you shine light at one frequency on a material you get out light with twice the frequency. This process is known as sum ~~or difference~~ frequency ~~mixing~~. ~~Two beams with frequency~~ ω<sub>1</sub> and ω<sub>2</sub> ~~when summed results in a frequency of 2 x~~ ω ~~also referred to as second harmonic generation (SHG) or, if~~ ω<sub>1</sub> – ω <sub>2</sub> results in ~~a zero~~ frequency ~~electric field this is a simple voltage also known as optical rectification~~.		One nonlinear optical phenomena is that when you shine light at one frequency on a material you get out light with twice the frequency. This process is known as second harmonic generation (SHG). SHG is a special type of sum frequency generation (SFG). SFG occurs when ω<sub>3</sub> = ω<sub>1</sub> and ω<sub>2</sub>. If ω<sub>3</sub> = ω<sub>1</sub> – ω<sub>2</sub>, this results in difference frequency generation (DFG). These processes are used to generate different frequencies of light, and thus new wavelengths of light can be used in experiments.

	The electronic charge displacement (polarization) induced by an oscillating electric field (e.g., light) can be viewed as a classical oscillating dipole that itself emits radiation at the oscillation frequency.		The electronic charge displacement (polarization) induced by an oscillating electric field (e.g., light) can be viewed as a classical oscillating dipole that itself emits radiation at the oscillation frequency.

Chrisb: /* Expression for Microscopic Nonlinear Polarizabilities */

2011-08-11T17:51:50Z

Expression for Microscopic Nonlinear Polarizabilities

← Older revision		Revision as of 10:51, 11 August 2011
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	:<math>\mu\,\!</math> is the microscopic nonlinear polarizability		:<math>\mu\,\!</math> is the microscopic nonlinear polarizability
	:<math>E_i E_k E_j\,\!</math> are the electric field (vectors)		:<math>E_i E_k E_j\,\!</math> are the electric field (vectors)
	:<math>\mu = \mu_0 \quad+\quad \alpha_{ij}E_j \quad+\quad \beta _{ijk}/ 2 E e \quad+\quad \gamma_{ijkl} / 6 E E E + ...\,\!</math>		:<math>\mu = \mu_0 \quad+\quad \alpha_{ij}E_j \quad+\quad \beta _{ijk}/ 2 E E \quad+\quad \gamma_{ijkl} / 6 E E E + ...\,\!</math>

	Where:		Where:

Cmditradmin: /* Expression for Microscopic Nonlinear Polarizabilities */

2011-01-19T17:23:40Z

Expression for Microscopic Nonlinear Polarizabilities

← Older revision		Revision as of 10:23, 19 January 2011
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	:<math>\alpha\,\!</math> is linear polarizability		:<math>\alpha\,\!</math> is linear polarizability
	:<math>\beta\,\!</math> is the [[first hyperpolarizability]] ( a third rank tensor with 27 permutations although some are degenerate)		:<math>\beta\,\!</math> is the [[first hyperpolarizability]] ( a third rank tensor with 27 permutations although some are degenerate)
	:<math>\gamma\,\!</math> is the second hyperpolarizability, responsible for third order non linear optics.		:<math>\gamma\,\!</math> is the [[second hyperpolarizability]], responsible for third order non linear optics.

	The terms beyond αE are not linear (they have exponential terms) in E and are therefore referred to as the nonlinear polarization and give rise to nonlinear optical effects. Note that E<sub>j</sub>, E<sub>k</sub>, and E<sub>j</sub> are vectors representing the direction of the polarization of the applied field with respect to the molecular coordinate frame. Molecules are asymmetric have different polarizabilities depending the direction of the applied electric field.		The terms beyond αE are not linear (they have exponential terms) in E and are therefore referred to as the nonlinear polarization and give rise to nonlinear optical effects. Note that E<sub>j</sub>, E<sub>k</sub>, and E<sub>j</sub> are vectors representing the direction of the polarization of the applied field with respect to the molecular coordinate frame. Molecules are asymmetric have different polarizabilities depending the direction of the applied electric field.