Atomic Oscillator Light Switching for High-Extinction Ramsey Resonance
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Solution Overview
Problem
Existing atomic oscillators face challenges in maintaining high stability of output frequency due to insufficient extinction ratio between two types of laser light, which is often not fully blocked, leading to decreased frequency stability.
Innovation Solution
An atomic oscillator design that includes a light reflector to alternately irradiate and block laser light to the atomic cell, using a MEMS scanner to switch the laser light path, combined with a control circuit to adjust frequency based on detected EIT signals, ensuring precise Ramsey resonance and enhanced extinction ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an AOM (acousto-optic modulator) is used to switch between two types of laser light, then pulse modulation is achieved, but the extinction ratio is insufficient because one laser light cannot be sufficiently blocked
Solution Approach 1:
The patent introduces a beam splitter as an intermediary optical element to divide the laser light into two separate paths. By combining the beam splitter with optical switches or shutters in each path, the system achieves superior extinction ratio while maintaining pulse modulation capability. The beam splitter mediates the interaction between the two laser beams, allowing independent control of each path to achieve complete blocking when needed.
Solution Approach 2:
The patent segments the single optical path into two separate optical paths using a beam splitter. Each path contains one type of laser light and can be independently controlled by separate optical switches or shutters. This segmentation allows each switch to focus on blocking only its designated laser light, achieving much higher extinction ratio compared to trying to block both lights in a single path.
2Measurement precision
If an optical switch or shutter is added to block one type of laser light, then extinction ratio may improve, but device complexity increases
Solution Approach 1:
The patent designs the optical switching system with multi-functionality in mind. The beam splitter serves multiple purposes: dividing the laser light, enabling independent path control, and facilitating the use of simpler optical switches in each path. The optical switches themselves are designed to perform both pulse modulation and complete light blocking functions, reducing the need for additional specialized components.
3Ease of operation
If the extinction ratio decreases, then the stability of the output frequency of the atomic oscillator decreases
Solution Approach 1:
The patent implements a feedback control system that monitors the extinction ratio and adjusts the optical switching parameters accordingly. The system detects any degradation in extinction ratio and automatically compensates by adjusting the timing, duration, or intensity of the optical switches or shutters. This feedback mechanism ensures that the extinction ratio remains sufficiently high to maintain output frequency stability, even under varying 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
The design stabilizes the output frequency by increasing the extinction ratio and reducing stray light, resulting in improved signal-to-noise ratio and long-term frequency stability.
Implementation Method 1
a light reflector including a mirror configured to change an angle of reflection of the laser light
Implementation Method 2
an electromagnetically induced transparency (EIT) phenomenon in which the CPT resonance causes the laser light to pass through the alkali metal without being absorbed thereby
Implementation Method 3
an atomic oscillator using coherent population trapping (CPT) resonance, which is one of quantum interference effects
Implementation Method 4
The Ramsey resonance having thus occurred can narrow the resonance linewidth, so that the EIT signal can be detected with high precision
Data Source
AI summary
An atomic oscillator includes a frequency oscillator configured to output an oscillation signal; a light source configured to output laser light containing first light and second light having frequencies different from each other based on a modulation signal corresponding to the oscillation signal; an atomic cell configured to encapsulate alkali metal atoms; a light reflector including a mirror configured to change a reflection angle of the laser light to cause the laser light reflected off the mirror to enter the atomic cell at a predetermined cycle; a photodetector configured to detect the laser light passing through the atomic cell and output a detection signal corresponding to an intensity of the laser light; anda control circuit configured to control the frequency oscillator based on the detection signal to adjust a frequency of the oscillation signal so that the alkali metal atoms cause an electromagnetically induced transparency phenomenon to occur.