Photonic Resonance Frequency Conversion via Bound States in the Continuum
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Solution Overview
Problem
Current frequency upconversion systems for mid-infrared radiation are limited by low conversion efficiency and narrow spectrum bandwidth, making it difficult to develop high-performance cameras for this spectral region.
Innovation Solution
A device with a conversion layer comprising nonlinear optical material and a surface structure that induces bound states in the continuum (BIC) optical mode, enabling efficient broadband conversion of optical signals from mid-infrared to visible wavelengths through nonlinear interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional nonlinear frequency conversion systems are used for mid-infrared radiation, then frequency conversion can be achieved, but the conversion efficiency is low and the spectrum bandwidth is narrow
Solution Approach 1:
The patent changes the physical parameters of the optical resonator by introducing a periodic modulation structure that creates bound states in the continuum (BIC) modes. This structural parameter change enables ultra-high Q-factors and resonant enhancement, simultaneously improving conversion efficiency and bandwidth for mid-infrared frequency conversion
Solution Approach 2:
The patent employs a composite structure combining nonlinear optical material with a periodic modulation pattern (such as photonic crystal or metasurface structure). This composite approach leverages both the nonlinear optical properties of the material and the resonant field enhancement of the BIC modes, achieving high efficiency and broadband conversion
2Illumination intensity
If mid-infrared radiation is used for imaging, then thermal imaging can be achieved, but the imaging resolution is limited by the wavelength
Solution Approach 1:
The patent introduces an intermediary frequency conversion process that transforms mid-infrared photons into visible or near-infrared photons through nonlinear optical interaction with BIC modes. This intermediary conversion enables the use of high-resolution visible/NIR detectors while preserving the thermal imaging capability, effectively decoupling the wavelength limitation from the detection resolution
3Productivity
If state-of-the-art frequency upconversion systems are used, then some conversion can be achieved, but both conversion efficiency and spectrum bandwidth are limited
Solution Approach 1:
The patent introduces dynamically tunable BIC modes through the periodic modulation structure, allowing the resonant frequencies to be adjusted across a broad spectrum. This dynamic capability enables the system to adapt to different mid-infrared wavelengths, simultaneously achieving high conversion efficiency and broadband operation
Solution Approach 2:
The patent utilizes the unique property of BIC modes that exist in the continuum spectrum by introducing a periodic modulation in the optical path. This creates an additional dimensional degree of freedom in the frequency domain, allowing access to ultra-high Q-factors and broadband resonant enhancement that conventional single-mode resonators cannot achieve
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 solution achieves ultra-high conversion efficiency and broad bandwidth, enabling applications such as night vision eyeglasses by upconverting ambient IR light into visible light, with infinite spatial resolution and reduced pump fluence requirements.
Implementation Method 1
Generation and detection of photons in these spectral ranges have been well studied and high-performance devices are commercially available. Besides, another spectral region covering longer wavelengths from 3 um ̃12 um (mid-infrared radiation, MIR) is also of interest since most thermal imaging devices work in this region. However, high-performance cameras for this spectral region are hard to make and the imaging resolution is limited by the wavelength. One potential solution is to upconvert the MIR photon into a visible or telecom one by using some nonlinear process such as sum-frequency generation (SFG).
Implementation Method 2
The conversion layer may be configured to convert, based on nonlinear interaction with the BIC optical mode, an incoming signal incident on the conversion layer from an incoming wavelength to a target wavelength.
Data Source
AI summary
Methods and systems are described for conversion of an optical signal. The device may comprise a conversion layer comprising a nonlinear optical material with a surface structure disposed to receive a pump signal and cause a bound states in the continuum (BIC) optical mode. The conversion layer may be configured to convert, based on nonlinear interaction with the BIC optical mode, an incoming signal incident on the conversion layer from an incoming wavelength to a target wavelength.