Lumped Plasmonic Diode for Optical Rectification

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Solution Overview

Problem

Current technologies lack efficient circuit elements like plasmonic lumped diodes and rectifiers that can function effectively at optical frequencies, similar to their microwave counterparts, for rectifying optical field displacement currents.

Innovation Solution

A plasmonic nanostructure with negative permittivity is paired with a nonlinear optical material to create a lumped diode/rectifier, where the induced dipole moment and displacement current are made nonsymmetric by choosing appropriate material properties and geometric dimensions, allowing for rectification of the optical electric field at IR and optical frequencies, enabling direct second-harmonic generation without filtering or phase matching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional circuit elements are used at optical frequencies, then the basic functionality of rectification is lost, but using plasmonic nanostructures introduces complexity in achieving diode-like asymmetry

Engineering Contradiction:

Improverectification functionality at optical frequenciesVSAvoidstructural asymmetry requirement

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by creating a plasmonic nanostructure where one end is capped with a nonlinear optical material while the other end remains uncapped or has different geometry. This structural asymmetry causes the displacement current to behave differently under positive versus negative optical electric field cycles, enabling rectification functionality at optical frequencies similar to conventional diodes at lower frequencies.

Inventive Principle:

Principle #4Asymmetry

2Ease of manufacture

If symmetric plasmonic nanostructures are used, then manufacturing is simpler, but optical field rectification cannot be achieved

Engineering Contradiction:

Improvenanostructure fabricationVSAvoidrectification performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by introducing a nonlinear optical material cap at one specific end of the plasmonic nanostructure, while the rest of the structure maintains simple geometry. This localized modification creates the necessary asymmetry for rectification without requiring complex fabrication throughout the entire structure, thus balancing manufacturability with functional reliability.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If lumped nanocircuit elements are developed, then circuit theory can be extended to optical frequencies, but efficient rectifying elements like diodes are still missing

Engineering Contradiction:

Improvecircuit theory applicabilityVSAvoidrectifier structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the rectifier into two distinct functional segments: a plasmonic nanostructure segment that provides the resonant optical response, and a nonlinear optical material cap segment that provides the rectifying nonlinearity. This segmentation allows each segment to be optimized independently while working together to achieve rectification, making the overall device more manageable and consistent with lumped circuit element design.

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration achieves rectification of optical field displacement current with a specific polarity, providing diode-like functionality and direct second-harmonic generation at optical frequencies, effectively addressing the need for efficient optical circuit elements.

Implementation Method 1

a plasmonic nanostructure with negative permittivity is paired with a nonlinear optical material to create a lumped diode/rectifier

Methodology Applied

Scientific EffectPlasmonic effect:

Implementation Method 2

the induced dipole moment and displacement current are made nonsymmetric by choosing appropriate material properties and geometric dimensions, allowing for rectification of the optical electric field

Methodology Applied

Scientific EffectNonlinear optical effect:

Implementation Method 3

enabling direct second-harmonic generation without filtering or phase matching

Methodology Applied

Scientific EffectSecond-harmonic generation: Second Harmonic Generation

Data Source

PatentUS8284477B2Lumped plasmonic “diode” and lumped plasmonic “rectifier” for optical field rectification and lumped optical second harmonic generation

Publication Date: 2012.10.09 THE TRUSTEES OF THE UNIV OF PENNSYLVANIA

AI summary

A lumped nanocircuit element design at IR and optical frequencies is provided that can effectively act as a lumped “diode” and a lumped “rectifier” for rectifying optical field displacement currents or optical electric field. The lumped nanocircuit element design can also act as a lumped second harmonic generator. The element is formed by juxtaposing an epsilon-negative nanoparticle with a nonlinear optical nanostructure.