Laser beam steering. Final report 14 Jun 1971--14 Jun 1972

Technical Report · Sun Oct 01 04:00:00 EDT 1972

OSTI ID:7328324

Lotspeich, J F; Wauk, M T

An electronic beam scanner for CO/sup 2/ lasers was designed and constructed. Specific requirements to be met were, i.e., three degree scan range, 100 resolvable beam positions, 6000 Hz raster scan in one dimension, and a capability for 100 W of 10.6 micrometer output. The device employs acousto-optic Bragg diffraction using germanium with a longitudinal acoustic wave and laser beam polarization in the crystallographic <111> direction. Sawtooth FM over a 27 MHz band centered near 100 MHz is used to provide the scan mechanism. A single small Ba2NaNB5O15 transducer provides sufficient acoustic beam divergence to yield a 3 deg. scan capability with a 1.4 dB falloff in output beam power at the scan limits. Direct-contact water cooling of the Ge crystal is provided to prevent thermal runaway. Cylindrical, reflective, telescopic optics are used for beam conditioning and recollimation. Computer calculations provided impedance characteristics and frequency response curves for general transducer design. Transducer bonding was done ultrasonically using thin metal films of Ag, Au, and Ag-In. The Ag-In gave best overall performance. An rf-to-acoustic conversion efficiency of 34% was achieved at band center (4.7 dB effective transduction loss). Radio frequency driver power required for 50 (70)% diffraction efficiency was 31 (49) W. (GRA)

• Research Organization: Hughes Research Labs., Malibu, CA (USA)
• OSTI ID: 7328324
• Report Number(s): AD-905 202
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420300* -- Engineering-- Lasers-- (-1989)
ACOUSTICS
BEAM MONITORING
BRAGG REFLECTION
CARBON DIOXIDE LASERS
DESIGN
FABRICATION
GAS LASERS
LASERS
MONITORING
OPTICAL SYSTEMS
REFLECTION