A Wide Area Bipolar Cascade Resonant Cavity Light Emitting Diode for a Hybrid Range-Intensity Sensor
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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This dissertation focused on the development of an illuminator for the HRIS. This illuminator enables faster image rendering and reduces the potential of errors in return signal data, that could be generated from extremely rough terrain. Four major achievements resulted from this work, which advance the field of 3-D image acquisition. The first is that the TJ is an effective current spreading layer for LEDs with mesa width up to 140 micrometers and current densities of approximately 1 x 10exp 6 Ampsquare centimeter. The TJ allows fabrication of an efficient illuminator, with required geometry for the HRIS to operate as a real-time 3-D imaging system. Secondly, a design for a Bipolar Cascade-Resonant Cavity Light Emitting Diode BC-RCLED has been accomplished, that will illuminate the FOV of the hybrid-ranged intensity system with a single sweep of the beam. This device is capable of producing approximately 330 milliWatts of output power. Additionally, from this work, key parameters for HRIS design were identified. Using a collection optic with a 15 centimeters diameter, an HRIS mounting height of 1.5 meters, and a detector integration time of 330 milliseconds, a SNR of 20 decibels was achieved. Lastly, we demonstrated that the BC-RCLED designed for the HRIS can deliver sufficient energy to produce the required SNR. Also, through parametric analysis, we determined that a system trade-off, between the collection optic diameter, and the integration time, results in an increase in the SNR from 20 to nearly 50, or extending the operational range from 50 to nearly 130 meters.
- Electrooptical and Optoelectronic Devices