Abstract

A reflective optics system is described that will uniformly heat or transfer momentum to a spherical target. Six laser beams or three split beams are incident along three mutually perpendicular axes. The beams are reflected from cones with a 45° half-angle onto an aspheric reflector wing shaped to impart uniform heat or momentum to the target. A sample calculation shows that, for a target sphere with 1.5 index of refraction, 93% of the energy incident on the target is transmitted into the target. For smaller indices, a greater fraction of the incident energy is imparted to the target. The design provides completely uniform transmitted light as well as nearly orthogonal distribution of light over the target and is relatively insensitive to alignment errors.

© 1983 Optical Society of America

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References

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  1. C. E. Thomas, Appl. Opt. 14, 1267 (1975).
    [CrossRef] [PubMed]
  2. K. A. Bruckner, J. E. Howard, Appl. Opt. 14, 1274 (1975).
    [CrossRef]
  3. D. G. Burkhard, D. L. Shealy, Sol. Energy 17, 221 (1975).
    [CrossRef]
  4. P. W. Rhodes, D. L. Shealy, Appl. Opt. 19, 3545 (1980).
    [CrossRef] [PubMed]
  5. D. R. MacQuigg, D. R. Speck, J. Opt. Soc. Am. 67, 250A (1976).

1980 (1)

1976 (1)

D. R. MacQuigg, D. R. Speck, J. Opt. Soc. Am. 67, 250A (1976).

1975 (3)

Bruckner, K. A.

Burkhard, D. G.

D. G. Burkhard, D. L. Shealy, Sol. Energy 17, 221 (1975).
[CrossRef]

Howard, J. E.

MacQuigg, D. R.

D. R. MacQuigg, D. R. Speck, J. Opt. Soc. Am. 67, 250A (1976).

Rhodes, P. W.

Shealy, D. L.

P. W. Rhodes, D. L. Shealy, Appl. Opt. 19, 3545 (1980).
[CrossRef] [PubMed]

D. G. Burkhard, D. L. Shealy, Sol. Energy 17, 221 (1975).
[CrossRef]

Speck, D. R.

D. R. MacQuigg, D. R. Speck, J. Opt. Soc. Am. 67, 250A (1976).

Thomas, C. E.

Appl. Opt. (3)

J. Opt. Soc. Am. (1)

D. R. MacQuigg, D. R. Speck, J. Opt. Soc. Am. 67, 250A (1976).

Sol. Energy (1)

D. G. Burkhard, D. L. Shealy, Sol. Energy 17, 221 (1975).
[CrossRef]

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Figures (8)

Fig. 1
Fig. 1

Two-dimensional representation of the optical system. Four of the incoming laser beams are designated by the arrows I1, I2, I3, and I4. The fifth and sixth beams are not shown; they are perpendicular to the plane of the drawing. Each beam is reflected from a conical reflector of half-angle 45°. The reflected beam travels from the conical surface C to an aspheric surface of revolution labeled A. The aspheric reflector concentrates the light onto a hemisphere of the spherical pellet located at the origin. The design provides angular space for supporting structures and diagnostic apparatus. The configuration has been optimized for maximum transmission of the incoming laser light into the sphere. The spherical pellet at the origin is not drawn to scale. By placing the reflector surfaces farther from the target or by staggering the distances of the units from the target, additional identical configurations can be added to the system so that 12, 18, 24, etc. lasers may be employed.

Fig. 2
Fig. 2

Three orthogonal collimated beams incident on a sphere. Three additional beams along the negative axes are not shown. If σx = σ0 cosα, σy = σ0 cosβ, σz = σ0 cosγ, the total flux onto dS is (σx cosα+σy cosβ + σz cosγ)dS = σ0(cos2α+ cos2β + cos2γ)dS = σ0dS, and the flux density over the sphere is uniform and equal to σ0.

Fig. 3
Fig. 3

Reflective-optics detail for one of the units in Fig. 1 but with the inner reflector C shown as an asphere, while the outer A is a flat conical ring.

Fig. 4
Fig. 4

Split-ring geometry with a shaped inner reflector.

Fig. 5
Fig. 5

Planar view of a reflector unit from Fig. 1 showing typical ray path.

Fig. 6
Fig. 6

Lower figure: fraction of energy transmitted into sphere as a function of asphere radius xin for n = 1.5 and n = 1.1; all beams. Upper figure: fraction of incident energy reflected from sphere as a function of θ for n = 1.5 and n = 1.1; single beam.

Fig. 7
Fig. 7

Energy transmitted onto and into sphere as a function of θ, for n = 1.5, for a single beam.

Fig. 8
Fig. 8

Fraction of energy transmitted to sphere from single beam as a function of θ; n = 1.5.

Equations (17)

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E = σ x cos α + σ y cos β + σ z cos θ ,
E = σ 0 ( cos 2 α + cos 2 β + cos 2 θ ) = σ 0 ,
E = σ x τ ( α ) cos α + σ y τ ( β ) cos β + σ z τ ( θ ) cos θ ,
p ( z ) = p ( θ ) cos θ + p ( θ ) r ( θ ) cos θ p ( θ ) τ ( θ ) cos θ s .
p ( z ) = p ( θ ) f ( θ ) cos θ ,
f ( θ ) = [ cos θ + r ( θ ) cos θ τ ( θ ) cos θ s ] / cos θ = 1 + r ( θ ) τ ( θ ) cos θ s / cos θ .
P = p ( α ) f ( α ) cos α + p ( β ) f ( β ) cos β + p ( θ ) f ( θ ) cos θ .
p ( α ) = p 0 cos α / f ( α ) , p ( β ) = p 0 cos β / f ( β ) , p ( θ ) = p 0 cos θ / f ( θ ) ,
P = p 0 ( cos 2 α + cos 2 β + cos 2 θ ) = p 0
p = [ p ( θ ) sin θ p ( θ ) r ( θ ) sin θ p ( θ ) τ ( θ ) sin θ s ] θ ˆ = p ( θ ) g ( θ ) θ ˆ ,
g ( θ ) = sin θ r ( θ ) sin θ τ ( θ ) sin θ s ,
E = E 0 cos 2 θ / τ ( θ ) ,
2 π R 2 0 θ E ( θ ) sin θ d θ = 2 π 0 R σ ( x ) x d x .
A = a 2 ( N · a ) N ,
N = ( z I K ) / ( 1 + z 2 ) 1 / 2 , A = [ 2 z I + ( z 2 1 ) K ] / ( 1 + z 2 ) ,
A x A z = 2 z z 2 1 = x R sin θ z + R cos θ .
z = l + ( l 2 + 1 ) 1 / 2 ,

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