Abstract

We have demonstrated a high-efficiency grating (>80%) using a three-layer Stratified Volume Diffractive Optical Element (SVDOE). Its angular sensitivity was measured optically and shown to agree extremely well with simulations performed using rigorous coupled wave analysis (RCWA). Further simulations predict an increase in efficiency as the number of layers is increased. An SVDOE consists of binary grating layers interleaved with homogeneous layers. The binary grating layers are shifted laterally relative to each other to emulate a volume holographic grating with slanted fringes. Creating the slanted fringe structure permits the preferred incidence angle of the SVDOE to be rotated to any arbitrary position. Achieving the relative offset between grating layers is the most challenging fabrication step and required the development of a high-precision alignment technique that was implemented on a contact mask aligner. The approach is based on monitoring the diffraction signal of a beam that is transmitted through gratings on the substrate and those on the mask as they are translated with respect to one another during pre-exposure alignment. The homogeneous layers are fabricated using a polymer material, SU-8, that is spin-coated and then planarized during its curing process.

© 2002 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |

  1. D.M. Chambers and G.P. Nordin, �??Stratified volume diffractive optical elements as high-efficiency gratings,�?? J. Opt. Soc. Am. A 16, 1184-1193, (1999).
    [CrossRef]
  2. M.G. Moharam, D.A. Pommet, E.B. Grann, and T.K. Gaylord, �??Stable implementation of the rigorous coupled-wave analysis for surface-relief gratings: enhanced transmittance marix approach,�?? J. Opt. Soc. Am. A 12, 1077-1086, (1995).
    [CrossRef]
  3. Y. Torii and Y. Mizushima, �??Theory of alignment monitoring by diffraction from superimposed dual gratings,�?? J. Opt. Soc. Am. 68, 1716-1731, (1978).
    [CrossRef]
  4. Y. Torii and Y Mizushima, �??Optical ultramicrometer technique utilizing a composite diffraction grating,�?? Opt. Commun. 23, 135-138 (1977).
    [CrossRef]
  5. D.C. Flanders, H.I. Smith, and S. Austin, �??A new interferometric alignment technique,�?? Appl. Phys. Lett. 31, 426-428 (1977).
    [CrossRef]
  6. K. Kodate, T. Kamiya, and M Kamiyama, �??Double diffraction in the Fresnel region,�?? Japl J. of App. Phy. 10, 1040-1045, (1971).
    [CrossRef]
  7. K. Kodate, T. Kamiya, H. Takenaka, and H., Yanai, �??Double diffraction of phase gratings in the Fresnel region,�?? Jap. J. of App. Phy. 14, 1323-1334, (1975).
    [CrossRef]
  8. S. Noda, N Yamamoto, M Imada, H Kobayashi, and Makoto Okano, �??Alignment and stacking of semiconductor photonic bandgaps by wafer-fusion,�?? J. Lightwave Tech. 17, 1948-1955, (1999).
    [CrossRef]
  9. High Performance Diode Lasers, Models 56IMS001, 56IMS005 and 56IMS009 Operator�??s Manual, Melles Griot.
  10. Personal communication with Melles Griot.

Appl. Phys. Lett. (1)

D.C. Flanders, H.I. Smith, and S. Austin, �??A new interferometric alignment technique,�?? Appl. Phys. Lett. 31, 426-428 (1977).
[CrossRef]

J. Lightwave Tech. (1)

S. Noda, N Yamamoto, M Imada, H Kobayashi, and Makoto Okano, �??Alignment and stacking of semiconductor photonic bandgaps by wafer-fusion,�?? J. Lightwave Tech. 17, 1948-1955, (1999).
[CrossRef]

J. Opt. Soc. Am. (1)

J. Opt. Soc. Am. A (2)

Jap. J. of App. Phy. (1)

K. Kodate, T. Kamiya, H. Takenaka, and H., Yanai, �??Double diffraction of phase gratings in the Fresnel region,�?? Jap. J. of App. Phy. 14, 1323-1334, (1975).
[CrossRef]

Japl J. of App. Phy. (1)

K. Kodate, T. Kamiya, and M Kamiyama, �??Double diffraction in the Fresnel region,�?? Japl J. of App. Phy. 10, 1040-1045, (1971).
[CrossRef]

Opt. Commun. (1)

Y. Torii and Y Mizushima, �??Optical ultramicrometer technique utilizing a composite diffraction grating,�?? Opt. Commun. 23, 135-138 (1977).
[CrossRef]

Other (2)

High Performance Diode Lasers, Models 56IMS001, 56IMS005 and 56IMS009 Operator�??s Manual, Melles Griot.

Personal communication with Melles Griot.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (9)

Fig. 1.
Fig. 1.

Schematic illustration of the stratified volume diffractive optic element (SVDOE) structure. Binary grating layers are interleaved with homogeneous layers to achieve high efficiency. The gratings are shifted relative to one another, much like standard fringes in a volume grating, as a means to control the preferred incidence angle.

Fig. 2.
Fig. 2.

Design parameters for a three layer prototype using measured refractive index values.

Fig. 3.
Fig. 3.

Example of double diffraction pattern in the 0th order by phase grating/amplitude grating with 4µm period. Separation is 25µm.

Fig. 4.
Fig. 4.

Example of double diffraction pattern in the 0th order by phase grating/amplitude grating with 4µm period. Separation is 50µm

Fig. 5.
Fig. 5.

Signal and ramp from an alignment scan. One period of the simulated signal is extracted from this curve to scale to one period of grating offset.

Fig. 6.
Fig. 6.

Illustration of scaling one period of the measured alignment curve, and its corresponding ramp voltage segment, to the period of grating offset derived from simulation. Final alignment parameters are determined from this scaled curve.

Fig. 7.
Fig. 7.

Example signal and PZT ramp voltage measured during a scan for final alignment.

Fig. 8.
Fig. 8.

SEM micrograph of example fabricated three-layer SVDOE

Fig. 9.
Fig. 9.

Diffraction efficiency (+1 Order) as a function of incidence angle for a fabricated three-layer SVDOE

Tables (1)

Tables Icon

Table 1. Structural parameters for fabricated three-layer SVDOE

Metrics