Hybrid Acousto-Optic Device for Mid-Infrared Transmission
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Solution Overview
Problem
Existing acousto-optical devices are not transparent in the mid-infrared wavelength range (3 to 20 micrometers) due to the chemical reactivity of materials used in the production of acoustic transducers, which react with mercury halides, limiting their application in this spectral domain.
Innovation Solution
A hybrid acousto-optic device with a lithium niobate transducer and an intermediate component, such as paratellurite, is used to generate pure shearing acoustic waves, minimizing contact between mercury halides and metal electrodes, and optimizing acoustic impedance matching to achieve efficient acoustic wave transmission without mode conversion or reflection losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If metal electrodes are used in the acoustic transducer, then the transducer can effectively generate acoustic waves, but the metal reacts with mercury halide crystal, causing chemical degradation and limiting device reliability
Solution Approach 1:
The patent introduces an intermediate layer between the metal electrode and the mercury halide crystal. This intermediate layer acts as a mediator that prevents direct chemical contact between the reactive metal and the crystal, thereby eliminating the harmful amalgamation reaction while still allowing acoustic wave transmission. The intermediate layer resolves the contradiction by decoupling the electrical-to-acoustic energy conversion function from the chemical interface.
2Adaptability or versatility
If conventional acousto-optical materials are used, then the devices can operate in visible and near-infrared ranges, but they are not transparent in the mid-infrared wavelength range (3 to 20 micrometers)
Solution Approach 1:
The patent changes the material parameters of the acousto-optical crystal from conventional materials (like paratellurite) to mercury halide crystals. This parameter change in the crystal's optical transmission characteristics enables operation in the mid-infrared spectral range (3 to 20 micrometers), extending the device's spectral adaptability while maintaining acousto-optical functionality.
3Device complexity
If direct contact between metal transducer and mercury halide is established, then device structure is simplified, but acoustic impedance mismatch causes reflection losses and mode conversion
Solution Approach 1:
The intermediate layer serves as an acoustic impedance matcher between the metal transducer and the mercury halide crystal. By introducing this intermediate medium with appropriate acoustic impedance characteristics, the patent reduces acoustic reflection and mode conversion losses at the interface, improving acoustic energy transmission efficiency while adding minimal 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 hybrid device enables efficient transmission of acoustic waves across the mid-infrared range with minimal losses, allowing for effective control of optical beams and applications such as high-resolution frequency filtering and temporal shaping of laser pulses.
Implementation Method 1
a hybrid acoustic transducer, comprising in particular a crystal of paratellurite... The material constituting said intermediate component is chosen to allow the transmission of pure shearing acoustic waves generated by said acoustic transducer
Implementation Method 2
Acousto-optical devices are used in the state of the art for various optical beam control applications... amplitude modulation, angular deviation, spectral filtering and temporal shaping of the pulses
Data Source
Figure 1~2
AI summary
The device has a mercury halide crystal (2) and a hybrid acoustic transducer (3) including a paratellurite crystal (1). An intermediate component (5) is fixed on a face (51) of the paratellurite crystal and on a face (52) of the mercury halide crystal, where the faces are in front of each other and parallel to each other. An angle is defined between axes of the paratellurite crystal and the mercury halide crystal to cancel or minimize the difference in acoustic impedance between acoustic propagation modes of the halide and paratellurite crystals.