Tunable Bi-Photon Source With Phase And Polarization Control
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Solution Overview
Problem
Existing bi-photon sources are inefficient, complex, and require intricate alignment, making them unsuitable for scalable and flexible applications in quantum computing, quantum sensing, and quantum encryption.
Innovation Solution
A tunable bi-photon system with adjustable efficiency, spectral output, and optical phase, utilizing a phase shifting and polarization control mechanism using a phase shifting and polarization control mechanism, utilizing a phase shifting wave plate and polarization rotating wave plates, along with temperature control of nonlinear crystals to produce indistinguishable photons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If parametric down-conversion is used to produce bi-photons, then single photons can be generated reliably, but the process is extremely inefficient with only one conversion per billion photons
Solution Approach 1:
The patent combines multiple down-conversion crystals in series within a single optical path, allowing sequential conversion events to accumulate. This merging of multiple low-probability events into a coordinated sequence increases overall bi-photon production efficiency while maintaining the reliability of single photon generation through the same parametric down-conversion mechanism.
Solution Approach 2:
The system performs preliminary polarization alignment and phase matching preparation before the actual down-conversion process. By pre-configuring the optical parameters and crystal orientations, the system maximizes the probability of successful conversion events, thereby improving productivity without compromising the reliability of photon generation.
2Reliability
If traditional bi-photon sources are used, then photon pairs can be generated, but intricate alignment is required making them unsuitable for scalable applications
Solution Approach 1:
The patent designs a modular crystal assembly where each crystal serves multiple functions: down-conversion, polarization filtering, and phase matching. This multi-functionality reduces the number of separate alignment components needed, thereby simplifying the overall system while maintaining reliable photon pair generation.
Solution Approach 2:
The system segments the down-conversion process into discrete crystal modules that can be independently optimized and assembled. Each segment is designed with built-in alignment features and standardized interfaces, reducing the cumulative alignment complexity that would arise from a monolithic design while ensuring reliable photon pair production.
3Ease of manufacture
If fixed wavelength bi-photon sources are used, then simple design is achieved, but spectral output cannot be tuned for different quantum applications
Solution Approach 1:
The patent incorporates temperature control mechanisms and adjustable optical parameters that allow the system to dynamically tune its spectral output. By making these parameters adjustable rather than fixed, the system maintains relatively simple manufacturing while achieving versatility across different quantum applications through controlled variation of operating conditions.
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
Enables efficient, scalable, and flexible production of entangled and heralded photons, suitable for quantum applications with precise wavelength control and reduced alignment complexity.
Implementation Method 1
the use of non-linear optical crystals that convert photons from a high frequency to a lower frequency, a process called parametric down-conversion. In the parametric down-conversion process, a 'pump' photon of wavelength λ is down-converted into two photons, each with wavelength 2λ
Implementation Method 2
a phase shifting wave plate positioned in the first optical path between the pump focusing optic and the first face of the nonlinear crystal element. The phase shifting wave plate is a variable wave plate positioned in the first optical path between the pump focusing optic and the first face of the non-linear crystal
Implementation Method 3
a polarization rotating pre-crystal wave plate positioned in the first optical path between either the phase shifting wave plate, if present, and the first face of the nonlinear crystal element. The polarization rotating pre-crystal wave plate may be a manually or electronically rotatable half-wave plate or variable wave plate
Implementation Method 4
a thermal element attached to the crystal holder. The thermal element can either heat or cool the assembly as desired. Varying the temperature of a non-linear crystal will result in a variation in the index of refraction of the crystal and, subsequently, will alter the wavelengths of the collinear signal and idler photons produced
Implementation Method 5
a polarization-maintaining fiber optic focusing device. The focusing device comprises one or more lenses to focus the fiber output. The first translating mount allows the x-translation, y-translation, tip, tilt, and focal point placement of the fiber output to be precisely adjusted
Data Source
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AI summary
The present invention provides devices, systems, and methods for producing bi-photons without the need for complex alignment or source design by the user. The invention provides a tunable source of high-brightness, high-visibility, bi-photons that can be configured for a number of applications.