DESIGN AND DEVELOPMENT OF A PHOTOMIXING DEVICE.
Abstract
A traveling-wave phototube (TWP) has been developed which is capable of photomixing optical signals of differing frequency content and detecting the resultant difference frequency signal (beat) over the ll to 20 Gc band. This represents the broadest bandwidth presently available in a practical photodetector. An important spectroscopic application of this tube would be in the examination of laser outputs. In addition to its photomixing capability, this TWP is a sensitive detector of amplitude modualtion of light over this same broad bandwidth. In operation the mixing of input light beams results in the photoemission of a current-modulated electron beam form the tube's S-l photocathode. The equivalent resistance which is a transfer function relating the circuit power output to the ac beam current input is constant (approximately 105 ohms for this tube) at low average beam currents and grows exponentially for currents about200microamperes. Experimental measurements of the equivalent resistance have been made by the recentlydeveloped shot noise technique. These data are compared with the predictions of a theoretical treatment which includes the effects of spacecharge, circuit loss, and asynchronous beam velocity. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 09, 1963
- Accession Number
- AD0422961
Entities
People
- D. E. Caddes
Organizations
- Sylvania Electric Products