Stacked Optical Sensor Arrangement for High Dynamic Range Laser Detection
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Solution Overview
Problem
Existing optical sensor arrangements fail to achieve the required dynamic range and temporal resolution for detecting pulsed laser sources, particularly those in the near-infrared range, as they often saturate and require multiple sensors with separate optics, increasing complexity and space requirements.
Innovation Solution
A sensor arrangement featuring two sensors stacked one behind the other, with matching spectral ranges and a common aperture and optic, where the first diode absorbs most incoming photons for high sensitivity and acts as a damping filter for the second diode, achieving a dynamic range of 6 orders of magnitude with a 1:1000 intensity ratio, and optionally using a partially mirrored layer to reduce diode thickness and radiation reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single sensor is used to detect laser radiation across a wide dynamic range, then the temporal resolution can be maintained, but the sensor saturates and cannot cover 6 orders of magnitude
Solution Approach 1:
The detection system is segmented into multiple sensors (first sensor and second sensor) arranged one behind the other, each detecting different intensity ranges of the same wavelength. The first sensor detects lower intensities while the second sensor detects higher intensities, collectively covering 6 orders of magnitude without saturation of individual sensors.
2Measurement precision
If two sensors with separate optics are used to cover the dynamic range, then the measurement precision improves, but the device complexity and space requirements increase
Solution Approach 1:
The patent merges the optical paths of two sensors by using a single common optic (lens or telescope) that focuses radiation onto both the first and second sensors simultaneously. This eliminates the need for separate optics for each sensor, reducing device complexity and space requirements while maintaining the ability to detect across 6 orders of magnitude.
Solution Approach 2:
The common optic serves multiple functions: it focuses radiation onto both sensors, defines the field of view for both detectors, and optimizes the effective aperture for the entire sensor arrangement. This multi-functional design reduces the total number of optical components required.
3Measurement precision
If the first diode is made thick to absorb most photons for high sensitivity, then the detection precision improves, but the second diode receives insufficient radiation for low sensitivity detection
Solution Approach 1:
A partially mirrored layer is introduced as an intermediary between the first and second diodes. This layer reflects a portion of the radiation that passes through the first diode onto the second diode, ensuring that the second diode receives sufficient radiation intensity for its low-sensitivity detection function while the first diode maintains high sensitivity through thick absorption.
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 enhances dynamic sensitivity while maintaining spectral wavelength range, reducing the number of components and space required, and allows for efficient processing of output signals from both diodes using the same signal processing circuits.
Implementation Method 1
A first diode D1 is located in the image plane of these optics, which converts the incident radiation into an electrical photocurrent
Implementation Method 2
the first diode absorbs most incoming photons for high sensitivity and acts as a damping filter for the second diode
Data Source
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AI summary
The invention relates to an optical sensor arrangement comprising a sensor (D1, D2) for detecting electromagnetic waves and an aperture assigned to the sensor, wherein, in order to detect the electromagnetic waves entering through the aperture, at least two sensors (D1, D2) arranged behind one another are provided, and wherein the operational spectral ranges of the sensors (D1, D2) arranged behind one another match, wherein the preceding sensor (D1) in each case - as seen in the direction of the incident radiation - forms an attenuation filter for the sensors (D2) arranged behind said sensor.