28 March 2016 Enhanced optical discrimination system based on switchable retroreflective films
Phillip Schultz, Jason C. Heikenfeld
Author Affiliations +
Abstract
Reported herein is the design, characterization, and demonstration of a laser interrogation and response optical discrimination system based on large-area corner-cube retroreflective films. The switchable retroreflective films use light-scattering liquid crystal to modulate retroreflected intensity. The system can operate with multiple wavelengths (visible to infrared) and includes variable divergence optics for irradiance adjustments and ease of system alignment. The electronic receiver and switchable retroreflector offer low-power operation (<4  mW standby) on coin cell batteries with rapid interrogation to retroreflected signal reception response times (<15  ms). The entire switchable retroreflector film is <1  mm thick and is flexible for optimal placement and increased angular response. The system was demonstrated in high ambient lighting conditions (daylight, 18k lux) with a visible 10-mW output 635-nm source out to a distance of 400 m (naked eye detection). Nighttime demonstrations were performed using a 1.5-mW, 850-nm infrared laser diode out to a distance of 400 m using a night vision camera. This system could have tagging and conspicuity applications in commercial or military settings.
© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE) 0091-3286/2016/$25.00 © 2016 SPIE
Phillip Schultz and Jason C. Heikenfeld "Enhanced optical discrimination system based on switchable retroreflective films," Optical Engineering 55(4), 045101 (28 March 2016). https://doi.org/10.1117/1.OE.55.4.045101
Published: 28 March 2016
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Cited by 1 scholarly publication.
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KEYWORDS
Retroreflectors

Eye

Light sources

Receivers

Optical filters

Free space optics

Liquid crystals

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