Atomic Clock Gas Cell With Folded Optical Path for Miniaturization
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Solution Overview
Problem
Conventional atomic clocks based on quartz oscillators are large and power-intensive, while miniaturized atomic clocks, such as coherent population trapping (CPT) type atomic clocks, face challenges in maintaining accuracy in a compact form.
Innovation Solution
An atomic frequency acquisition apparatus with a cell containing atomic gas, a surface-emitting laser light source, and a photodetecting section, featuring internal laser light reflection sections that extend the optical path, allowing for a smaller size without compromising accuracy, using reflection films and a curved surface to enhance light reflection and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical path length is increased to maintain accuracy, then the apparatus size increases, but miniaturization is required for practical application
Solution Approach 1:
The patent introduces reflection sections that fold the optical path in three-dimensional space, allowing the laser light to traverse a longer distance through the atomic gas by utilizing vertical and lateral reflections rather than a simple linear extension. This dimensional folding enables extended interaction length without proportional increase in overall apparatus volume.
Solution Approach 2:
The optical path is nested within the cell structure by using internal reflection surfaces that guide the light through multiple passes through the atomic gas. The light path is folded back and forth within the confined cell volume, effectively nesting the extended optical trajectory within the compact physical boundaries of the cell.
2Reliability
If conventional quartz oscillators are used, then frequency control is achieved, but the devices are bulky and power-intensive
Solution Approach 1:
The patent replaces the mechanical quartz oscillator system with an atomic resonance-based frequency reference. Instead of relying on mechanical vibration of quartz crystals, the system uses the natural resonance frequency of atoms (cesium or rubidium) as the frequency standard, eliminating the need for bulky mechanical components and reducing power consumption.
Solution Approach 2:
The invention changes the fundamental parameter used for frequency reference from mechanical oscillation frequency to atomic transition frequency. By utilizing the invariant natural frequency of atomic transitions, the system achieves superior frequency stability with lower power requirements compared to conventional quartz oscillators.
3Volume of moving object
If the cell volume is reduced for miniaturization, then the apparatus becomes compact, but the optical path length decreases affecting accuracy
Solution Approach 1:
The patent employs reflection sections positioned at strategic locations within the cell to fold the optical path in multiple dimensions. The laser light reflects off surfaces oriented at various angles, creating a zigzag or spiral trajectory that extends the effective path length through the atomic gas without increasing the linear dimensions of the cell.
Solution Approach 2:
The reflection sections utilize curved or angled surfaces to guide the laser light through multiple passes through the atomic gas. The curved reflection surfaces help maintain beam collimation while extending the interaction path, allowing the light to traverse the atomic gas repeatedly within the compact cell volume.
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 apparatus achieves a longer optical path within a smaller cell volume, maintaining high accuracy and sensitivity by exciting a greater number of cesium atoms, enabling efficient acquisition of time standard frequencies for atomic clocks.
Implementation Method 1
a laser light source that oscillates a laser light that enters the cell and excites the atomic gas
Implementation Method 2
laser light that enters the cell and excites the atomic gas
Implementation Method 3
the cell has at least a laser light reflection section inside thereof... the optical path of the laser light within the cell can be made longer
Implementation Method 4
a photodetecting section that detects the laser light that has passed through the cell
Data Source
AI summary
An atomic frequency acquisition apparatus includes: a cell enclosing atomic gas therein; a laser light source that oscillates a laser light that enters the cell and excites the atomic gas; and a photodetecting section that detects the laser light that has passed through the cell, wherein the cell has at least a laser light reflection section inside thereof.