The POWER codes for estimating reflected light into an off-axis optical fiber

Technical Report · Sat Mar 02 04:00:00 EST 1991

OSTI ID:5829768

Goosman, D R

We give a calculation for estimating the amount of laser light collected by an off-axis optical fiber for velocimetry applications. It is assumed that laser light emanating from a single optical fiber is transported to a Lambertian reflector by a two-element lens composed of three spherical surfaces; an off-axis optical fiber adjacent to the laser fiber collects the light used for velocimetry. Four Symphony spreadsheets -- POWER, POWERE, POWERX, and POWERX8 -- are available to trace rays from the laser fiber through the compound lens onto the Lambertian surface to calculate the blur due to spherical aberration and to being out of focus. POWER uses the most approximations and is the fastest, while POWERX8 is the most accurate and slowest. POWER assumes that the light distribution on the Lambertian reflector due to a point source within the laser fiber is flat out to either a maximum radius or an effective radius determined by the ray-tracing routine. This flat distribution is then convolved in two dimensions with the round shape of the laser fiber to provide an analytic formula for light incident on the reflecting surface vs radius. Tracing rays in reverse through the lens provides the size of the illumination at the fiber plane containing all of the light due to a point source at the reflector, as well as a smaller effective size. The radial distribution within this circle is assumed to be flat. POWERE calculates the actual radial distribution of light on the reflector due to a point source at the laser fiber in ten radial bins. However, the distribution at the fiber plane due to a point source at the reflector is still assumed to be flat, as in the POWER code. POWERX relaxes the assumption for POWERE by using ten radial bins at the fiber plane. POWERX8 is the same as POWERX, except that there are 20, rather than 10, bins at both the reflector and the fiber plane, and a fiber-plane illumination distribution is also calculated.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• Sponsoring Organization: DOE; USDOE, Washington, DC (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5829768
• Report Number(s): UCRL-LR-103225; ON: DE91011764
• Country of Publication: United States
• Language: English

Related Subjects

657002* -- Theoretical & Mathematical Physics-- Classical & Quantum Mechanics
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
99 GENERAL AND MISCELLANEOUS
990200 -- Mathematics & Computers
COMPUTER CODES
ELECTROMAGNETIC RADIATION
FIBERS
LAMBERT LAW
LASER RADIATION
LENSES
LIGHT SCATTERING
LIGHT TRANSMISSION
MEASURING INSTRUMENTS
OPTICAL FIBERS
OPTICAL REFLECTION
OPTICAL SYSTEMS
P CODES
RADIATIONS
REFLECTION
SCATTERING
VELOCIMETERS