Abstract

A kinoform that shapes the divergent beam from a semiconductor laser without using any other optical components was designed and fabricated. The kinoform-only concept means that the kinoform must perform both the actual beam shaping as well as focusing the divergent laser beam, correcting for the astigmatism of the laser, and correcting for the spherical aberration of the laser exit window. A rectangular beam of dimensions 1000 μm × 300 μm is formed 42 mm behind the kinoform. Of the total output from the laser, some 50% is incident upon the kinoform, of which ∼50% will appear in the rectangular beam. The intensity uniformity error within the rectangle increases from the design value of 8% to 38% because of sensitivity to fabrication errors. The kinoform-only design for beam-shaping applications requires high manufacturing accuracy but is attractive because a system using such a component is easily mounted and aligned and, with the use of kinoform-replication techniques, can be mass produced at low cost.

© 1996 Optical Society of America

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References

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    [CrossRef] [PubMed]
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1995 (2)

1994 (1)

1993 (1)

1990 (1)

G. Owen, “Methods for proximity effect correction in electron lithography,” J. Vac. Sci. Technol. B 8, 1889–1892 (1990).
[CrossRef]

1987 (1)

1982 (1)

Bengtsson, J.

Bolle, A.

Cordingley, J.

Duparré, M.

Ekberg, M.

Farn, M. W.

M. W. Farn, “New iterative algorithm for the design of phase-only gratings,” in Computer and Optically Generated Holographic Optics, I. Cindrich, S. H. Lee, eds., Proc. SPIE1555, 34–42(1991).
[CrossRef]

Golub, M. A.

Hård, S.

Jacobsson, S.

Larsson, M.

Lüdge, B.

Nikolajeff, F.

Owen, G.

G. Owen, “Methods for proximity effect correction in electron lithography,” J. Vac. Sci. Technol. B 8, 1889–1892 (1990).
[CrossRef]

Pavelyev, V. S.

Soifer, V. A.

Uspleniev, G. V.

Veldkamp, W. B.

Volotovskii, S. G.

Appl. Opt. (6)

J. Vac. Sci. Technol. B (1)

G. Owen, “Methods for proximity effect correction in electron lithography,” J. Vac. Sci. Technol. B 8, 1889–1892 (1990).
[CrossRef]

Other (1)

M. W. Farn, “New iterative algorithm for the design of phase-only gratings,” in Computer and Optically Generated Holographic Optics, I. Cindrich, S. H. Lee, eds., Proc. SPIE1555, 34–42(1991).
[CrossRef]

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Figures (15)

Fig. 1
Fig. 1

Schematic diagram of a setup of the kinoform-only beam-shaping system. Distances are in micrometers.

Fig. 2
Fig. 2

Intensity distribution for the light incident upon the kinoform.

Fig. 3
Fig. 3

Desired intensity distribution in the diffraction plane used in the calculations.

Fig. 4
Fig. 4

Algorithm used in step 1.

Fig. 5
Fig. 5

Phase distribution in the kinoform plane from the calculation.

Fig. 6
Fig. 6

Intensity in the diffraction plane from the phase distribution of Fig. 5 and the intensity distribution of Fig. 2 in the kinoform plane.

Fig. 7
Fig. 7

Procedures involved in step 2 and in the preparations for kinoform fabrication.

Fig. 8
Fig. 8

Ray trace from the laser source to the kinoform to determine the phase distribution of the light incident upon the kinoform.

Fig. 9
Fig. 9

Optical path length (relative to the central ray) for a ray as a function of the distance to the optical axis when the ray reaches the kinoform in Fig. 8 (solid curve). To obtain the correct path length parallel to the small divergence axis of the laser, one must add the astigmatism-correction value (dashed curve, divided by 10).

Fig. 10
Fig. 10

Upper and central parts of the fabricated kinoform. The abrupt changes in shading between the matrices result from image processing to make the smaller periods appear more distinct.

Fig. 11
Fig. 11

Intensity distribution in the diffraction plane from the kinoform in Fig. 10, obtained with the setup from Fig. 1. The white reference bar is 500 μm.

Fig. 12
Fig. 12

Intensity contour map of the intensity distribution shown in Fig. 11.

Fig. 13
Fig. 13

Total intensity distribution falling on a screen 42 mm behind the kinoform. The reference bar is 10 mm.

Fig. 14
Fig. 14

Intensity distribution in the diffraction plane when the laser is moved 30 μm closer to the kinoform than that from Fig. 11. The reference bar is 500 μm.

Fig. 15
Fig. 15

Intensity distribution in the diffraction plane when the laser is moved 30 μm farther away from the kinoform than thatfrom Fig. 11. The reference bar is 500 μm.

Tables (1)

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Table 1 Some Semiconductor Laser Data Necessary for the Calculation of the Kinoform

Equations (2)

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uniformity error = I max I min I max + I min ,
PSF ( r ) = 1 π ( 1 + η ) [ 1 α 2 exp ( r 2 α 2 ) + η β 2 exp ( r 2 β 2 ) ] ,

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