Optical Frequency Mixing Light Source for Wavelength-Tuned Beam Scanning
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Solution Overview
Problem
Current compact display devices, such as head-mounted displays, require compact and efficient light sources that can provide variable focusing and redirection of light beams with high selectivity and tunability, which is challenging due to the bulkiness of existing mirror-based beam scanners and varifocal lens assemblies, and the lack of readily available compact, high-monochromatic visible laser sources.
Innovation Solution
A light source system utilizing nonlinear optical frequency mixing of tunable and fixed lasers to generate wavelength-tunable visible light, employing optical frequency mixers and quasi-phase-matched nonlinear optical elements, such as poled crystalline materials, to produce red, green, and blue light beams with adjustable wavelengths and power levels, enabling efficient beam redirection and refocusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mirror-based beam scanners and varifocal lens assemblies are used for variable focusing and redirection of light beams, then beam control capability is improved, but device size and weight increase
Solution Approach 1:
The patent replaces mechanical beam scanning systems (mirrors and varifocal lenses) with an acoustic-optic modulator that uses acoustic waves to diffract and redirect light beams. This substitution eliminates bulky mechanical components while maintaining beam redirection capability, directly resolving the contradiction between beam control and device weight.
2Weight of stationary object
If compact display devices are miniaturized for wearable applications, then device portability is improved, but available optical component size decreases
Solution Approach 1:
The acoustic-optic modulator replaces traditional mechanical optical components with a compact solid-state device that uses acoustic field modulation. This allows for significant miniaturization of the display device while maintaining full optical functionality, enabling wearable applications.
Solution Approach 2:
The patent changes the operating parameters by using acoustic frequency modulation (2-100 MHz range) to control light beam properties instead of mechanical movement. This parameter change enables compact component design while maintaining beam control capabilities.
3Speed
If rapid wavelength tuning is implemented for beam scanning, then scanning speed is improved, but spectral linewidth increases
Solution Approach 1:
The acoustic-optic modulator enables rapid wavelength tuning through electrical control of acoustic wave generation, achieving 200 kHz tuning speed without the mechanical inertia limitations of traditional systems. The acoustic wave's ability to create precise diffraction patterns maintains narrow spectral linewidth despite the high tuning speed.
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 solution provides a compact, high-selectivity light source capable of rapid wavelength tuning up to 200 kHz with a narrow spectral linewidth, enabling efficient beam scanning and refocusing, suitable for wearable displays and other miniaturized applications.
Implementation Method 1
an optical frequency mixer coupled to the first laser and to the plurality of second lasers for nonlinear optical mixing of optical frequencies of the light emitted by the first laser and the light emitted by each one of the plurality of second lasers, to provide a plurality of output light beams at mixed optical frequencies
Implementation Method 2
employing optical frequency mixers and quasi-phase-matched nonlinear optical elements, such as poled crystalline materials, to produce red, green, and blue light beams with adjustable wavelengths and power levels
Implementation Method 3
The nonlinear optical element may include a poled crystal. The poled crystal may be configured for providing an output beam at a doubled optical frequency of the tunable laser
Data Source
AI summary
A light source based on an optical frequency mixer is disclosed. The light source has a first laser for emitting light at a first optical frequency, and a plurality of second lasers for emitting light at different second optical frequencies. The optical frequency mixer provides output light beams at mixed optical frequencies of the first and second lasers. Wavelength of output light beams may be tuned by tuning wavelength of any of the first or second lasers. In this manner, RGB wavelength-tunable light sources may be constructed based on red or near-infrared lasers. The wavelength tunability of the output light beams may be used to angularly scan or refocus the light beams.