Discrete Spectrum Broadband Optical Source for SD-OCT
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Optical Coherence Tomography (OCT) systems, particularly Spectral Domain (SD)-OCT, face limitations in imaging speed due to low power density of available light sources, which necessitates longer signal integration times, compromising between sensitivity and speed.
Innovation Solution
A discrete spectrum broadband light source is configured using a broadband optical gain medium within a reflector cavity with controlled reflectivity, producing a spectrum with high peak power emission lines that match the spatial distribution of detector arrays, enhancing detection sensitivity and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a broadband light source with low power density is used in SD-OCT, then sensitivity is maintained, but imaging speed decreases due to longer signal integration times required
Solution Approach 1:
The patent applies local quality by creating a light source with non-uniform spectral distribution, specifically generating discrete high-power emission lines at specific wavelengths rather than uniform broadband emission. The gain medium is configured with cavity feedback to produce peak power emission lines that concentrate optical power at specific spectral locations, allowing high power density at detectors while maintaining overall broadband coverage for sensitivity.
Solution Approach 2:
The patent changes the spectral parameter of the light source from uniform broadband distribution to discrete line spectrum with high peak power. By adjusting the cavity feedback and gain medium characteristics, the system transforms the emission profile to achieve high power density at specific wavelengths, directly addressing the speed-sensitivity tradeoff by enabling faster detection without sacrificing sensitivity.
2Productivity
If the spectral distribution of the light source is matched to the spatial distribution of detector arrays, then detection speed and sensitivity are enhanced, but the complexity of source configuration increases
Solution Approach 1:
The patent applies self-service by designing a system where the gain medium's spontaneous emission spectrum naturally provides the discrete line structure when combined with cavity feedback. The system self-configures the spectral distribution to match detector requirements through the physical interaction of spontaneous emission with the optical cavity, reducing the need for external spectral shaping components and simplifying overall system configuration.
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 new light source significantly increases imaging speed and sensitivity by providing higher optical power at each detector, allowing for faster signal processing and improved image acquisition without compromising sensitivity.
Implementation Method 1
a broadband optical gain medium placed within a reflector cavity... the cavity gain is adjusted to operate in a linear amplifier mode without reaching a lasing threshold... Output spectrum of the broadband source comprises amplified emission lines having high peak power
Implementation Method 2
reflector cavity is constructed with a very low reflectivity front reflective surface and a high reflectivity back reflective surface... cavity gain is adjusted to operate in a linear amplifier mode
Data Source
AI summary
A new broadband source having a discrete set of spectral emission lines having high peak power in each line is provided by placing a gain medium in a reflective cavity comprising reflective front and back surfaces. A cavity feedback factor less than unity is achieved by providing reflectivity of one surface substantially lower than the reflectivity of the other surface such that spontaneous emission in the gain medium is linearly amplified just below the lasing threshold. In an alternative arrangement, a movable external back surface placed at a prescribed distance from the gain medium provides a means to achieve a free spectral range and finesse of the emission lines to match a pitch of a detector array in a SD-OCT system. By simultaneously providing high power to each detector element of the array, sensitivity and imaging speed of SD-OCT system are significantly improved.