We show that for dielectric or metallic gratings with square-wave geometry the photon eigenfunctions in the grating region can be expressed in analytical form. there is an enhancement of the local-(surface-) field intensity by a factor of 100 -500.For molecules on a grating surface, such increase in local fields can imply an amplification of 10 -3 X 10' for the Raman scattering signal.
We present the general principle of wavelength-selective enhancement of absorption in thin-film solar cells by a periodic grating substrate. By exact numerical calculation we demonstrate that substantial short-circuit current gains are realizable in thin-film amorphous silicon (a-SiHx) solar cells. In particular, for a 0.5-μm-thick a-SiHx solar cell, optimal texturing of an Ag substrate to form a one-dimensional reflective grating can yield a 2-mA/cm2 enhancement over the flat substrate case. For a two-dimensional cross-hatched grating substrate the enhancement is estimated to be 3.5–4 mA/cm2.
Abstract.It is well known that the calculation of an accurate approximate derivative f'(x) of a nontabular function fix) on a finite-precision computer by theis a delicate task. If ft is too large, truncation errors cause poor answers, while if ft is too small, cancellation and other "rounding" errors cause poor answers. We will show that by using simple results on the nature of the asymptotic convergence of d(ft) to /', a reliable numerical method can be obtained which can yield efficiently the theoretical maximum number of accurate digits for the given machine precision.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.