Self-collimation in photonic crystal structures: a new paradigm for applications and device development

Abstract

In this paper, we report on the development of the self-collimation phenomenon in photonic crystal structures for integrated optics applications. In addition, detailed numerical analysis, design procedures, fabrication and characterization techniques are included. Applications presented in this paper include: channelless waveguiding, orthogonal bending of light, tunable beam splitter, all-optical analog-to-digital converter, reconfigurable optical switch, chemical/gas sensor and a three-dimensional optical interconnect bus.

Self-collimation in PT -symmetric crystals

“…Diffraction-free propagation of narrow beams, being of fundamental interest in wave dynamics, is especially significant for photonic integrated circuits [1]. Bessel and Airy beams are among the most common examples of nondiffractive beams, which in an ideal case are spatially infinite.…”

Acoustic guiding and subwavelength imaging with sharp bending by sonic crystal

“…Because a substantial range of the evanescent modes of the point source has been canalized across the SC, the formed image will have subwavelength resolution. Thus it 5 can be seen that the guiding and bending channel discussed above also possesses the abilities to transport some subwavelength information of the source and to image.…”

“…In the case of wave guiding, self-collimation allows varying over a wide range of incident angles and still maintaining a narrow range of propagations along with a low-loss transmission. This type of waveguide does not depend on physical channels to confine waves, thus it gains many advantages over conventional line-defect based wave guides, for which introducing of physical boundaries in SCs or PCs leads to extra coupling loss and Fresnel reflection loss [3,5]. Moreover, profited from a long flat equifrequency contour (EFC), evanescent modes of a source placed at the input port of such waveguides can also be canalized to the output port [8,9], thus self-collimation waveguides possess a promising prospect in subwavelength applications.…”

“…Suitable designing of a SC gives the phenomenon called self-collimation, by which a beam of acoustic wave can propagate in SCs with almost no diffraction along a definite direction [1,2]. This interesting phenomenon, also reported in Photonic crystals (PCs) [3][4][5], affords a promising way to control the flow of waves, thus it has been utilized for various wave-functional applications, such as the wave beaming [6,7], subwavelength imaging [8,9] and wave guiding [10].…”

Efficient light coupling from integrated single-mode waveguides to supercollimating photonic crystals on silicon-on-insulator platforms

“…Supercollimation in particular gives the possibility to propagate light over the centimetre scale without the use of structural waveguides. Recent studies report the possibility to realize devices such as optical routers, multiplexers or polarization splitters, by incorporating linear defects in periodic structures 6,7 or alternatively by using graded PhCs 8 . In fact, supercollimating PhCs are the building block of many promising applications and it seems very likely that they will play a key role in future telecommunications technologies.…”