Frozen Shockwave Frequency Modulation in Photonic Band Gap Structures
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Solution Overview
Problem
Current methods for modulating electromagnetic radiation frequencies, such as using nonlinear crystals, Doppler shifting, and cavity tuning, face limitations in achieving a continuous dynamic range and often result in undesirable noise or limited frequency shifts.
Innovation Solution
A method and device utilizing a photonic band gap structure with a stationary shockwave and an acoustic pulse generator to modulate electromagnetic radiation, where the acoustic pulse Doppler shifts the frequency of the radiation within the structure, allowing for continuous and tunable frequency shifts without damaging the crystal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a propagating shockwave is used to modulate frequency, then frequency modulation is achieved, but the photonic crystal is destroyed and the method is suitable for one-time use only
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a static photonic crystal to a dynamic system where a shockwave propagates through the crystal lattice. This dynamic approach allows frequency modulation while the crystal structure temporarily deforms and recovers, enabling repeated use rather than single-use destruction
Solution Approach 2:
The patent changes the physical parameters of the photonic crystal by inducing a shockwave that temporarily alters the lattice spacing and refractive index. These parameter changes are transient and reversible, allowing the crystal to return to its original state and be used again, resolving the contradiction between achieving frequency modulation and maintaining crystal durability
2Productivity
If a propagating shockwave is used to modulate frequency, then frequency modulation is achieved, but undesirable noise is created in the radiation output
Solution Approach 1:
The patent employs periodic action by using a continuous or repeated train of shockwaves rather than a single propagating shockwave. This periodic stimulation creates a steady-state condition where the photonic crystal responds in a predictable, repeatable manner, reducing random noise in the output radiation while maintaining frequency modulation capability
Solution Approach 2:
The patent achieves continuity of useful action by maintaining a continuous or periodically renewed shockwave field within the photonic crystal. This continuous action stabilizes the frequency modulation process and reduces transient noise effects that occur with single-shot propagating shockwaves, improving the quality of the radiation output
3Productivity
If Doppler shifting is used to shift frequency, then continuous shifting is achieved, but all frequencies are shifted by the same amount without discrimination
Solution Approach 1:
The patent applies local quality by creating regions within the photonic crystal with different lattice structures, refractive indices, or shockwave coupling characteristics. This allows different frequency components of the input radiation to experience different Doppler shifts or modulation depths, providing frequency selectivity and discrimination while maintaining continuous frequency shifting capability
Solution Approach 2:
The patent segments the photonic crystal into multiple zones or layers with different properties, where each segment interacts with specific frequency ranges differently. This segmentation enables selective frequency modulation, allowing certain frequencies to be shifted more than others, thus resolving the contradiction between continuous shifting and frequency discrimination
4Productivity
If cavity tuning is used to shift frequency, then frequency modulation is achieved, but the cost is high and the frequency shift range is limited
Solution Approach 1:
The patent replaces the mechanical cavity tuning system with an acoustic shockwave-based frequency modulation approach. Instead of physically adjusting cavity dimensions or using complex mechanical tuning mechanisms, the invention uses acoustic waves to dynamically modulate the photonic crystal's optical properties, achieving frequency shifts with simpler, more cost-effective equipment
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 approach enables a significant and continuous dynamic range of frequency modulation with reduced noise, allowing for up to 15-20% frequency shift, and can be cascaded for greater flexibility and higher frequency shifts, making it suitable for various applications including thermal signature modulation.
Implementation Method 1
The acoustic pulse passing through the photonic band gap structure Doppler shifts the frequency of the radiation
Implementation Method 2
a photonic band gap structure having a stationary shockwave therein
Data Source
Figure 1~2
Figure 3~4
AI summary
A system (10) and method for modulating the frequency of electromagnetic radiation utilizes a frozen Shockwave (26) in a photonic band gap structure (12). The structure provides a discontinuity (24) in lattice constant that functions as a Shockwave, and that does not shift its position within the structure. In addition the modulation device or structure includes an acoustic pulse generator (14), such as a piezoelectric transducer coupled to one end of the photonic band gap structure. The acoustic pulse generator may be driven to produce a periodic pulse (44) in the photonic band gap structure. The frozen Shockwave, a defect or discontinuity in the photonic band gap structure, is used to hold incoming electromagnetic radiation in place. The acoustic pulse passing through the photonic band gap structure Doppler shifts the radiation. The frequency-shifted radiation is then ejected out of the frozen Shockwave portion of the photonic band gap structure.