Abstract

Ferrimagnetic iron garnet films are investigated as current-sensing elements. The Faraday effect within the films permits measurement of the magnetic field or current by a simple polarimetric technique. Polarized diffraction patterns from the films have been observed that arise from the presence of magnetic domains in the films. A physical model for the diffraction is discussed, and results from a mathematical analysis are in good agreement with the experimental observations. A method of current sensing that uses this polarized diffraction is demonstrated.

© 1995 Optical Society of America

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References

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  1. M. N. Deeter, A. H. Rose, G. W. Day, “Fast, sensitive magnetic-field sensors based on the Faraday effect in YIG” IEEE J. Lightwave Technol. 8, 1838–1842 (1990).
    [CrossRef]
  2. The samples were kindly supplied by S. Licht of AT&T Bell Laboratories, Murray Hill, NJ 07974.
  3. J. A. Davis, J. M. Waas, “Current status of the magneto-optic spatial light modulator,” in Spatial Light Modulators and Applications III, U. Efron, ed., Proc. Soc. Photo-Opt. Instrum. Eng.1150, 334–345 (1989).
  4. M. Waring, “Polarized beam splitting effect in heterogeneously magnetized magneto-optic films,” in Optical Information Processing Systems and Architecture, B. Javidi, ed., Proc. Soc. Photo-Opt. Instrum. Eng.1151, 567–576 (1989).
  5. R. Wolfe, E. M. Gyorgy, R. A. Lieberman, V. J. Fratello, S. J. Licht, M. N. Deeter, G. W. Day, “High frequency magnetic field sensors based on the Faraday effect in garnet thick films,” in Proceedings of the IEEE 8th Optical Fiber Sensors Conference (Institute of Electrical and Electronics Engineers, New York, 1992), pp. 390–392.
    [CrossRef]

1990 (1)

M. N. Deeter, A. H. Rose, G. W. Day, “Fast, sensitive magnetic-field sensors based on the Faraday effect in YIG” IEEE J. Lightwave Technol. 8, 1838–1842 (1990).
[CrossRef]

Davis, J. A.

J. A. Davis, J. M. Waas, “Current status of the magneto-optic spatial light modulator,” in Spatial Light Modulators and Applications III, U. Efron, ed., Proc. Soc. Photo-Opt. Instrum. Eng.1150, 334–345 (1989).

Day, G. W.

M. N. Deeter, A. H. Rose, G. W. Day, “Fast, sensitive magnetic-field sensors based on the Faraday effect in YIG” IEEE J. Lightwave Technol. 8, 1838–1842 (1990).
[CrossRef]

R. Wolfe, E. M. Gyorgy, R. A. Lieberman, V. J. Fratello, S. J. Licht, M. N. Deeter, G. W. Day, “High frequency magnetic field sensors based on the Faraday effect in garnet thick films,” in Proceedings of the IEEE 8th Optical Fiber Sensors Conference (Institute of Electrical and Electronics Engineers, New York, 1992), pp. 390–392.
[CrossRef]

Deeter, M. N.

M. N. Deeter, A. H. Rose, G. W. Day, “Fast, sensitive magnetic-field sensors based on the Faraday effect in YIG” IEEE J. Lightwave Technol. 8, 1838–1842 (1990).
[CrossRef]

R. Wolfe, E. M. Gyorgy, R. A. Lieberman, V. J. Fratello, S. J. Licht, M. N. Deeter, G. W. Day, “High frequency magnetic field sensors based on the Faraday effect in garnet thick films,” in Proceedings of the IEEE 8th Optical Fiber Sensors Conference (Institute of Electrical and Electronics Engineers, New York, 1992), pp. 390–392.
[CrossRef]

Fratello, V. J.

R. Wolfe, E. M. Gyorgy, R. A. Lieberman, V. J. Fratello, S. J. Licht, M. N. Deeter, G. W. Day, “High frequency magnetic field sensors based on the Faraday effect in garnet thick films,” in Proceedings of the IEEE 8th Optical Fiber Sensors Conference (Institute of Electrical and Electronics Engineers, New York, 1992), pp. 390–392.
[CrossRef]

Gyorgy, E. M.

R. Wolfe, E. M. Gyorgy, R. A. Lieberman, V. J. Fratello, S. J. Licht, M. N. Deeter, G. W. Day, “High frequency magnetic field sensors based on the Faraday effect in garnet thick films,” in Proceedings of the IEEE 8th Optical Fiber Sensors Conference (Institute of Electrical and Electronics Engineers, New York, 1992), pp. 390–392.
[CrossRef]

Licht, S.

The samples were kindly supplied by S. Licht of AT&T Bell Laboratories, Murray Hill, NJ 07974.

Licht, S. J.

R. Wolfe, E. M. Gyorgy, R. A. Lieberman, V. J. Fratello, S. J. Licht, M. N. Deeter, G. W. Day, “High frequency magnetic field sensors based on the Faraday effect in garnet thick films,” in Proceedings of the IEEE 8th Optical Fiber Sensors Conference (Institute of Electrical and Electronics Engineers, New York, 1992), pp. 390–392.
[CrossRef]

Lieberman, R. A.

R. Wolfe, E. M. Gyorgy, R. A. Lieberman, V. J. Fratello, S. J. Licht, M. N. Deeter, G. W. Day, “High frequency magnetic field sensors based on the Faraday effect in garnet thick films,” in Proceedings of the IEEE 8th Optical Fiber Sensors Conference (Institute of Electrical and Electronics Engineers, New York, 1992), pp. 390–392.
[CrossRef]

Rose, A. H.

M. N. Deeter, A. H. Rose, G. W. Day, “Fast, sensitive magnetic-field sensors based on the Faraday effect in YIG” IEEE J. Lightwave Technol. 8, 1838–1842 (1990).
[CrossRef]

Waas, J. M.

J. A. Davis, J. M. Waas, “Current status of the magneto-optic spatial light modulator,” in Spatial Light Modulators and Applications III, U. Efron, ed., Proc. Soc. Photo-Opt. Instrum. Eng.1150, 334–345 (1989).

Waring, M.

M. Waring, “Polarized beam splitting effect in heterogeneously magnetized magneto-optic films,” in Optical Information Processing Systems and Architecture, B. Javidi, ed., Proc. Soc. Photo-Opt. Instrum. Eng.1151, 567–576 (1989).

Wolfe, R.

R. Wolfe, E. M. Gyorgy, R. A. Lieberman, V. J. Fratello, S. J. Licht, M. N. Deeter, G. W. Day, “High frequency magnetic field sensors based on the Faraday effect in garnet thick films,” in Proceedings of the IEEE 8th Optical Fiber Sensors Conference (Institute of Electrical and Electronics Engineers, New York, 1992), pp. 390–392.
[CrossRef]

IEEE J. Lightwave Technol. (1)

M. N. Deeter, A. H. Rose, G. W. Day, “Fast, sensitive magnetic-field sensors based on the Faraday effect in YIG” IEEE J. Lightwave Technol. 8, 1838–1842 (1990).
[CrossRef]

Other (4)

The samples were kindly supplied by S. Licht of AT&T Bell Laboratories, Murray Hill, NJ 07974.

J. A. Davis, J. M. Waas, “Current status of the magneto-optic spatial light modulator,” in Spatial Light Modulators and Applications III, U. Efron, ed., Proc. Soc. Photo-Opt. Instrum. Eng.1150, 334–345 (1989).

M. Waring, “Polarized beam splitting effect in heterogeneously magnetized magneto-optic films,” in Optical Information Processing Systems and Architecture, B. Javidi, ed., Proc. Soc. Photo-Opt. Instrum. Eng.1151, 567–576 (1989).

R. Wolfe, E. M. Gyorgy, R. A. Lieberman, V. J. Fratello, S. J. Licht, M. N. Deeter, G. W. Day, “High frequency magnetic field sensors based on the Faraday effect in garnet thick films,” in Proceedings of the IEEE 8th Optical Fiber Sensors Conference (Institute of Electrical and Electronics Engineers, New York, 1992), pp. 390–392.
[CrossRef]

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Figures (6)

Fig. 1
Fig. 1

Measured Faraday rotation angle versus calculated magnetic field within a solenoid. Sample was BIG film, AT&T wafer 2311, 315 μm thick, designed to be a Faraday isolator at 1.3 μm (rotation of 130°/mm and magnetic saturation ≤320 Oe). The two sets of data points correspond to two different solenoids with different numbers of turns.

Fig. 2
Fig. 2

Vidicon image of a diffraction pattern of the 1.15-μm laser beam transmitted through BIG film. The scale permits measurement of the diffraction angle. The diffraction pattern was circular; ellipticity is due to distortion when the pattern was recorded.

Fig. 3
Fig. 3

Pattern of magnetic domains in a BIG film determined by photographing through crossed polarizers (from Ref. 5).

Fig. 4
Fig. 4

Conceptualization of the process by which magnetic domains create diffraction: (a) domains are either up or down; (b) polarization rotation is ±Ө, depending on whether the domain is up or down; (c), (d), projections of the polarization vertically and horizontally, showing that the vertical component keeps its initial polarization and is undeviated by the domains whereas the horizontal component experiences a p phase grating with a period two domains in width.

Fig. 5
Fig. 5

Theoretical calculation of the expected diffraction pattern using a width of 40 ± 10 μm and a Gaussian beam of 1 mm.

Fig. 6
Fig. 6

Current-induced Faraday rotation angle, determined by measurement of the ratio between light in the diffraction ring compared with light transmitted in the central spot, as a function of applied current, using Eq. (10). The sample was BIG film, AT&T wafer 2532, 470 μm thick, designed for Faraday isolation at 1.5 μm (rotation of 90°/mm and magnetic saturation at ≤320 Oe).

Equations (11)

Equations on this page are rendered with MathJax. Learn more.

H = N I / L ,
P / P 0 = ( 1 / 2 ) [ 1 ± sin ( 2 Ө ) ] .
P 1 P 2 P 1 + P 2 = 2 Ө .
H = I 2 π R ,
I / I 0 = sin 2 Φ Φ 2 exp [ 2 [ w 0 ( Φ ± π ) / W ] 2 ] ,
k W sin ϕ ± π = 0 or sin ϕ = ± λ / ( 2 W ) .
P r P r ( 0 ) + δ P r = C sin 2 Ө + 2 C cos Ө sin Ө δӨ,
P s P s ( 0 ) + δ P s = C cos 2 Ө 2 C cos Ө sin Ө δӨ .
P r P s P r + P s R = sin 2 Ө cos 2 Ө + 4 sin Ө cos Ө δӨ,
δӨ ( I ) = R ( I ) R ( 0 ) 4 sin Ө cos Ө .
δӨ ( I ) = R ( I ) R ( 0 ) 2 [ 1 R ( 0 ) 2 ] 1 / 2 .

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