SiO2-on-MgF2 Photonic Platform for UV-Vis Waveguiding
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Solution Overview
Problem
Current integrated photonic platforms struggle to operate effectively in the ultraviolet (UV) and visible (vis) wavelength range due to strong optical absorption and the inability to miniaturize sensing devices for handheld applications.
Innovation Solution
A photonic material platform utilizing silicon dioxide as the optical guiding layer and magnesium fluoride as the substrate layer, which provides high optical quality and refractive index difference suitable for UV-vis waveguiding, while being compatible with existing microelectronics and photonics technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If integrated photonic materials such as silicon nitride are used to operate in the visible range, then the device can function at shorter wavelengths, but strong optical absorption occurs in the UV range
Solution Approach 1:
The patent employs a composite material structure consisting of silicon dioxide (SiO2) as the waveguide core and magnesium fluoride (MgF2) as the cladding layer. This composite approach combines two materials with complementary properties: SiO2 provides high refractive index for effective waveguiding, while MgF2 offers extremely low optical absorption in the UV range. The combination enables the device to operate across both visible and UV wavelengths without suffering from strong absorption losses that plague single-material systems.
2Reliability
If the refractive index difference between substrate and guiding layer is increased to provide optical waveguiding condition, then waveguiding efficiency improves, but waveguide dimensions become extra-small at short wavelengths
Solution Approach 1:
The patent carefully selects and optimizes the refractive index parameters of the constituent materials. Silicon dioxide has a refractive index of approximately 1.46-1.55 in the visible range, while magnesium fluoride has a refractive index of about 1.38-1.40. This creates a moderate refractive index difference (Δn ≈ 0.08-0.15) that is sufficient to establish effective optical waveguiding conditions through total internal reflection, yet small enough to allow the design of waveguides with practical dimensions in the sub-micron to micron range, avoiding the need for excessively small features that would be difficult to fabricate.
3Adaptability or versatility
If table-top and bulky optical devices are used for UV-vis sensing applications, then optical functionality is achieved, but the devices cannot be miniaturized for handheld applications
Solution Approach 1:
The patent replaces traditional mechanical/optical bench-top components with integrated photonic circuit elements fabricated on a chip. Complex optical functions such as wavelength separation, filtering, and sensing that previously required bulky mechanical devices are now implemented using planar waveguides, gratings, and resonators etched into the SiO2/MgF2 substrate. This substitution of mechanical optical systems with integrated photonic circuits enables miniaturization while preserving full UV-vis sensing functionality, making handheld portable devices feasible.
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 platform enables the design of single-mode waveguides with sub-micron dimensions, facilitating the development of compact photonic devices such as sensors and spectrometers that can operate efficiently across the UV-vis spectrum.
Implementation Method 1
The refractive index difference between silicon dioxide and magnesium fluoride is large enough to provide optical waveguiding condition in the UV-vis range
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3A~3C
AI summary
In one aspect, a photonic device includes a substrate layer comprising magnesium fluoride and an optical guiding layer disposed on the substrate layer. The optical guide layer includes silicon dioxide. The substrate layer and the optical guide layer are transparent at an ultraviolet and visible wavelength range. In another aspect, a method includes oxidizing silicon to form a silicon dioxide layer, bonding the silicon dioxide layer to magnesium fluoride, removing the silicon and performing lithography and etching of the silicon dioxide to form a photonic device.