title: Design of flat-band superprism structures for on-chip spectroscopy.
abstract: We present a systematic design procedure of photonic crystal (PhC) superprism structures for on-chip spectroscopic applications. In specific, we propose a new figure of merit, namely the angular-group-dispersion-bandwidth-product (AGDBP) to quantitatively describe the spectroscopic performance of PhC superprism structures, and an optimum PhC structure for spectroscopic applications should have large angular group dispersion over a large bandwidth, i.e., a flat-top dispersion profile. We demonstrate the advantage of such a new design consideration by optimizing the geometry of a two-dimensional parallelogram-lattice PhC superprism structure. The performance of such a superprism spectrometer is further analyzed numerically using finite-difference time-domain simulations, which out-performs current implementations in terms of the number of achievable output spectral channels.
authors.forename: Boshen
authors.initials: B
authors.lastname: Gao
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Shi
authors.forename: Robert W
authors.initials: RW
authors.lastname: Boyd