**7. References**


**16** 

*USA* 

C. W. Wong et al.,\*

*Columbia University, New York, NY* 

**Negative Index Photonic Crystals** 

**Superlattices and Zero Phase Delay Lines** 

An intense interest in negative index metamaterials (NIMs) [1-2] has been witnessed over the last years. Metal based NIMs [3-11] have been demonstrated at both microwave and infrared frequencies with a motivation mainly coming from the unusual physical properties and potential use in many technological applications [12-21]; however, they usually have large optical losses in their metallic components. As an alternative, dielectric based photonic crystals (PhCs) have been shown to emulate the basic physical properties of NIMs [22-26] and, in addition, have relatively small absorption loss at optical frequencies. Equally important, PhCs can be nanofabricated using currently available silicon chip-scale foundry processing, allowing significant potential in the development of future electronic-photonic

One particular type of PhC can be obtained by cascading alternating layers of NIMs and positive index materials (PIMs) [27 – 32]. This photonic structure (with an example shown in Figure 1) is postulated to show unusual and unique optical properties including new types of surface states and gap solitons [33], unusual transmission and emission properties [34 – 38], complete photonic bandgaps [39], and phase-invariant field that can be effectively used in cloaking applications [40]. Moreover, a remarkable property of these binary photonic structures is the existence of an omnidirectional bandgap that is insensitive to the wave polarization, angle of incidence, structure periodicity, and structural disorder [41 – 43]. The main reason for the occurrence of a bandgap with such unusual properties is the existence of a frequency band at which the path-averaged refractive index is equal to zero [27 – 32, 34].

S. Kocaman1, M. S. Aras1, P. Hsieh1, J. F. McMillan1, C. G. Biris2, N. C. Panoiu2, M. B. Yu3, D. L. Kwong3

*= (* n *ω/c)*

*= mπ*, is satisfied for *m* = 0,

**1. Introduction** 

integrated circuits.

 \*

and A. Stein4

*1,4USA 2UK 3Singapore* 

<sup>1</sup>*Columbia University, New York, NY, 2University College of London, London, 3Institute of Microelectronics, Singapore, 4Brookhaven National Laboratory, Upton, NY,* 

Specifically, at this frequency the Bragg condition, *k*

