High Power Infrared Modulator.
Abstract
This report describes an amplitude modulator designed to operate in conjunction with a CW carbon monoxide laser as it was developed and tested under contract No. F33615-75-C-1018, entitled 'High Power Infrared Modulator'. Although specific modulation requirements were stated for this effort, the approach selected was to have the potential for extended capabilities. The mechanism chosen to provide the modulation at the 5 micron wavelength region was the FTIR (Frustrated Total Internal Reflection) principle. By placing two BaF2 (Barium Floride) prisms in close proximity to each other and varying their spacing with the aid of piezo-electric transducers, modulation of the throughput was achieved. The device has a clear aperture of 2 centimeters and can handle an input laser beam in excess of 250 watts. The modulation produces a nominally square wave pulsed output with a rise and fall times of less than .5 milliseconds. A completely codeable system, its pulsed output can be varied in frequency and duty cycle from less than 100 Hertz to greater than 150 Hertz while maintaining a variable duty cycle capability from less than 20 percent to greater than 80 percent. The extinction ratio is better than 50:1 with greater than 85 percent total switching efficiency. This allows for an average throughput of greater than 100 watts at a 50 percent duty setting.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1976
- Accession Number
- ADA027135
Entities
People
- Ronald R. Selleck
Organizations
- Martin Marietta