Phase-Conjugate External Resonator for Stable Harmonic Lasers
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Solution Overview
Problem
Conventional higher harmonic wave generating laser apparatuses require complex and precise control and adjustment of nonlinear optical crystals for stable high-output operation, including precise alignment and optical axis control, which is cumbersome and costly.
Innovation Solution
Incorporating a nonlinear optical crystal as a phase conjugate mirror in an external resonator, allowing the phase conjugate wave to automatically adjust the optical axis and lock the wavelength and phase of the laser beam, eliminating the need for precise alignment and control of the resonator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional internal resonator or external resonator configurations are used with nonlinear optical crystals, then high-output laser beam generation is achieved, but complex and highly precise control and adjustment are required for optical axis and resonator length
Solution Approach 1:
The phase conjugate mirror automatically performs optical axis alignment and resonator length adjustment through the phase conjugation process itself. The phase conjugate wave naturally travels back along the exact path of the incident wave, causing the nonlinear optical crystal and mirrors to automatically face each other without requiring external alignment mechanisms or precise manual adjustment.
Solution Approach 2:
The phase conjugate mirror provides automatic feedback control for the resonator system. By generating a phase conjugate wave that exactly reverses the incident wave's phase and direction, the system self-corrects any deviations in optical axis alignment or resonator length, maintaining stable high-output operation without external intervention.
2Reliability
If precise alignment and control are performed for stable high-output operation, then reliable laser oscillation is achieved, but the apparatus becomes cumbersome and costly
Solution Approach 1:
The phase conjugate mirror performs self-alignment by automatically adjusting its orientation through the phase conjugation process. The phase conjugate wave naturally returns along the incident path, causing the nonlinear optical crystal to automatically face the mirrors without requiring precise manual alignment during assembly, greatly simplifying manufacturing.
Solution Approach 2:
The patent replaces complex mechanical alignment mechanisms and precision adjustment devices with an optical field-based phase conjugation process. Instead of using mechanical means to precisely position and orient components, the system uses the inherent properties of phase conjugate waves to achieve automatic alignment, reducing mechanical complexity and cost.
3Manufacturing precision
If nonlinear optical crystal is precisely positioned for wavelength conversion, then visible and ultraviolet laser beams are obtained, but environmental fluctuations affect resonator stability
Solution Approach 1:
The phase conjugate mirror provides continuous feedback that compensates for environmental disturbances. When environmental factors cause deviations in the optical path or resonator geometry, the phase conjugation process automatically adjusts to maintain the correct optical alignment, stabilizing the resonator against external fluctuations.
Solution Approach 2:
The resonator system performs self-correction of alignment deviations caused by environmental factors through the phase conjugation mechanism. The phase conjugate wave automatically adjusts its path to maintain optimal interaction with the nonlinear optical crystal, making the system self-stabilizing against temperature changes, vibrations, and other environmental disturbances.
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 stable high-output laser beam generation in the visible and ultraviolet regions with a simpler apparatus design, reducing costs and minimizing environmental fluctuations' impact on resonator stability.
Implementation Method 1
Incorporating a nonlinear optical crystal as a phase conjugate mirror in an external resonator, allowing the phase conjugate wave to automatically adjust the optical axis and lock the wavelength and phase of the laser beam
Implementation Method 2
a matter that phase conjugate wave is generated (or produced) by making a laser beam enter an optical material to form in the inside thereof coarse/fine distribution of period equivalent to a wavelength of the laser beam, has been known. The principle of the coarse/fine distribution formation is described as nonlinear optical effect
Implementation Method 3
In order to obtain laser beam in visible region and ultraviolet region, higher harmonic wave generating technology using nonlinear optical crystal in addition to laser oscillator has been used widely
Implementation Method 4
there is a need to perform highly precise alignment adjustment for angle, temperature, and the like of the nonlinear optical crystal for generating higher harmonic wave
Data Source
AI summary
A laser apparatus includes: a laser oscillator that includes a mirror and emits a laser beam; and an external resonator that includes a nonlinear optical crystal that functions as a phase conjugate mirror. The phase conjugate mirror reflects the laser beam and produces a phase conjugate wave that reaches the mirror of the laser oscillator, and the mirror of the laser oscillator and the phase conjugate mirror cause laser oscillation such that a wavelength and a phase of the laser beam oscillated by the laser oscillation are automatically fixed.