Chip-Scale NMR Gyroscope VCSEL Beam Orientation
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Solution Overview
Problem
Chip-scale NMR gyrosopes face challenges in orienting orthogonal pump and probe light beams within the atomic vapor chamber, leading to high resource consumption and independent beam performance issues, which complicates their cooperation and reduces signal quality and accuracy.
Innovation Solution
A physical unit for a chip-scale NMR gyroscope incorporating a VCSEL, a silicon sheet with a recess and reflecting mirrors, a glass sheet, an atomic vapor chamber, a quarter-wave plate, and a polarizing beam splitter, where the laser beam is divided into orthogonal pump and probe beams using right angle prisms and mirrors, ensuring coherence and efficient interaction within the chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a glass-silicon-glass sandwich structure is adopted for the atomic vapor chamber, then the chamber can be constructed with standard MEMS processing, but it becomes difficult to orient the pump light beam and probe light beam orthogonally in the light-atom interaction region
Solution Approach 1:
The patent introduces a fourth dimension by etching a recess into the silicon sheet, creating a three-dimensional light-atom interaction region. This allows the pump and probe beams to enter from different faces of the recess and intersect orthogonally within the chamber, solving the orientation problem while maintaining the planar MEMS fabrication approach.
Solution Approach 2:
The atomic vapor chamber is formed by nesting the glass sheet over the recessed silicon sheet, creating a contained interaction region within the larger MEMS structure. This nested configuration allows complex optical paths to be achieved within a compact footprint.
2Adaptability or versatility
If two independent semiconductor lasers are used to provide pump and probe light beams, then the beams can be independently controlled, but temperatures, frequencies, and powers must be separately controlled resulting in large resource consumption
Solution Approach 1:
The patent merges the functions of two independent lasers into a single semiconductor laser source. The single laser beam is split into pump and probe beams using optical elements, reducing resource consumption while maintaining independent control capabilities through optical modulation and polarization manipulation.
Solution Approach 2:
The single laser beam is segmented into two separate functional beams (pump and probe) using beam splitting and polarization control. This allows one laser to serve multiple functions that would otherwise require two separate laser systems.
3Adaptability or versatility
If two independent semiconductor lasers are used, then beam performance can be independently adjusted, but this results in difficulties in cooperation of the two light beams under working conditions
Solution Approach 1:
By using a single laser source, the patent ensures inherent coherence and synchronization between the pump and probe beams. The beams are derived from the same oscillating medium, guaranteeing stable phase relationships and frequency coherence, which eliminates cooperation difficulties while still allowing independent intensity control through optical modulation.
4Device complexity
If the atomic vapor chamber uses a glass-silicon-glass sandwich structure with orthogonal light beams, then pump and probe beams can be orthogonal within the interaction region, but it is difficult to couple the light into the atomic vapor chamber
Solution Approach 1:
The recess etched into the silicon sheet creates a vertical dimension that allows light coupling from the top surface. The pump and probe beams can be coupled through different faces of the recessed chamber, achieving orthogonal orientation while maintaining easy coupling access without requiring side-entry configurations.
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 configuration enables low-cost, efficient production of orthogonal light beams, improving NMR signal quality and accuracy by facilitating better light-atom interaction and reducing resource consumption, while allowing for easy integration and increased volume for light-atom interaction.
Implementation Method 1
a vertical cavity surface emitting laser (VCSEL)
Implementation Method 2
A laser beam is transmitted from the VCSEL and is divided into a reflection beam and a transmission beam when passing through the first right angle prism
Implementation Method 3
The transmission beam passes through the quarter-wave plate and is reflected by a second reflecting mirror into the atomic vapor chamber as a pump light beam
Implementation Method 4
The reflection beam is reflected by a first reflecting mirror into the atomic vapor chamber as a probe light beam
Implementation Method 5
The probe light beam after interacting with the atoms is reflected by a third reflecting mirror and is divided by the polarizing beam splitter into two beams
Implementation Method 6
the two beams are detected by the photodetectors, respectively
Implementation Method 7
The atomic vapor chamber is filled with alkali metal atoms, one or a plurality of inert gas atoms, and one or a plurality of buffer gases
Data Source
AI summary
A physical unit of a chip-scale nuclear magnetic resonance (NMR) gyroscope, the physical unit including: a vertical cavity surface emitting laser (VCSEL), a silicon sheet including a recess, a glass sheet, an atomic vapor chamber, a first right angle prism, a quarter-wave plate, a polarizing beam splitter, and photodetectors. The recess includes sides including reflecting mirrors. The glass sheet is disposed on the silicon sheet. The recess of the silicon sheet is in a structure of an inverted square frustum, and the reflecting mirrors are disposed on sides of the recess. The atomic vapor chamber is an enclosed region formed between the recess and the glass sheet. The atomic vapor chamber is filled with alkali metal atoms, one or a plurality of inert gas atoms, and one or a plurality of buffer gases.