Surface Plasmon Resonance Sensor with Nonlinear Dielectric Film
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Solution Overview
Problem
Conventional surface and localized plasmon resonance sensors exhibit low sensitivity due to small changes in reflectivity during resonance, limiting their ability to accurately detect reactions between probes and object substances.
Innovation Solution
A surface plasmon resonance sensor is designed with a substrate and a dielectric film having a nonlinear optical effect, where the surface plasmon resonance is detected by measuring changes in the second-order harmonic component of reflected light, enhancing sensitivity through the use of lead zirconate titanate (PZT) or non-lead inorganic nonlinear optical materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional surface or localized plasmon resonance sensors are used, then the sensor structure is simple, but the sensitivity is low due to small changes in reflectivity during resonance
Solution Approach 1:
The patent employs a composite structure combining a metal film (for plasmon generation) with a nonlinear optical film (for harmonic generation). This composite material approach enables the system to simultaneously achieve plasmon resonance and nonlinear optical effects, resulting in significantly enhanced sensitivity compared to conventional single-material sensors.
Solution Approach 2:
The patent utilizes changes in the nonlinear optical properties of the film under plasmon resonance conditions. By measuring the second-order harmonic component of reflected light, which exhibits large intensity changes during resonance, the system achieves high sensitivity detection without requiring complex structural modifications.
2Measurement precision
If conventional plasmon resonance sensors are used, then the device is easy to manufacture, but the detection precision is limited by small reflectivity changes
Solution Approach 1:
The patent replaces the conventional measurement approach (direct reflectivity measurement) with a nonlinear optical measurement approach (second-order harmonic component measurement). This substitution transforms the detection mechanism to exploit nonlinear optical effects, achieving superior detection precision while maintaining manufacturing feasibility through standard thin-film deposition techniques.
3Measurement precision
If a nonlinear optical film is added to enhance sensitivity, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent exploits parameter changes in the optical properties of the nonlinear optical film under plasmon resonance conditions. The film's second-order nonlinear optical coefficient enables generation of harmonic components with large intensity variations during resonance, achieving high sensitivity through material property utilization rather than structural complexity.
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
The sensor achieves high sensitivity by significantly increasing the intensity of the second-order harmonic wave, allowing for precise detection of changes in resonance conditions due to reactions between probes and object substances, with enhanced peak detection capabilities.
Implementation Method 1
a dielectric film having a nonlinear optical effect on a first surface of the substrate... The component of the reflected light is caused by the nonlinear optical effect
Implementation Method 2
A plasmon resonance is produced by resonating a surface plasmon generated on the first surface of the substrate with an evanescent wave generated on a second surface of the substrate by incident light
Implementation Method 3
When light enters into the prism under a condition of total reflection, an evanescent wave develops on a surface opposite to the reflecting surface of the metal film, and is coupled with surface plasmon on the metal film
Data Source
AI summary
A surface plasmon resonance sensor includes a substrate, a dielectric film having a nonlinear optical effect on a first surface of the substrate, and a probe fixed to the dielectric film. A plasmon resonance is produced by resonating a surface plasmon generated on the first surface of the substrate with an evanescent wave generated on a second surface of the substrate by incident light radiated to the second surface. The plasmon resonance is detected by measuring a change of a component of light reflected on the second surface of the substrate. The component of the reflected light is caused by the nonlinear optical effect. This surface plasmon resonance sensor has a high measuring sensitivity.