Spot size and effective focal length measurements for a fast axial flow CO{sub 2} laser
- Naval Air Warfare Center, China Lake, CA (United States)
- Sandia National Labs., Albuquerque, NM (United States)
An evaluation of the variation in focal plane position and spot size for a 1,650 W fast axial flow CO{sub 2} laser was performed. Multiple measurements of the focused beam were taken at stepped intervals along the beam axis to create a composite representation of the focus region. Measurements were made at several power levels from low to full power for each of five nominally identical lenses. It was found that as laser output power increases, the minimum focused spot radius increases, and the position of minimum focus shifts toward the laser resonator. These effects were attributed to observed variations in the diameter of the beam entering the focusing lens. For the ZnSe (f = 127 mm) lenses examined, variations in spot radius and focal plane position were seen. Lenses with high rated absorption had a larger variation in spot size and effective focal length than those with low absorption. Lenses that had previously been degraded by welding had the greatest variation.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 658456
- Report Number(s):
- SAND--97-1301C; CONF-971149--; ON: DE98005902; BR: DP0102023
- Country of Publication:
- United States
- Language:
- English
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