Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electromagnetic Field Tapering in the High-Roughness Substrates Coated
  by a Thin Film of Manganese: A Lithography-Free Approach to Ultra-Broadband,
  Wide-Angle, UV to FIR Perfect Absorption   Metallic layers are known to be used for the suppression of wave transmission
when their thickness is sufficiently higher than the skin depth of metal. If in
addition to blocking the transmission, metallic layers have the feature of
blocking the reflection, too, they would make perfect absorbers. In this work,
we propose an experimental approach of using a single thin layer of Manganese
(Mn) as both the transmission suppresser and the reflection suppresser. This
approach leads to obtaining lithography-free ultra-broadband perfect absorption
in an ultra-wide spectrum ranging from Ultraviolet (UV) to Far Infrared (FIR).
The measured average absorption is approximately 99%. Such a promising result
can be achieved by only coating a single Mn layer on high-roughness substrates
that include random nano-pyramids on it. In other words, we do not need a stack
of different materials and combinations of geometrical features. The high
roughness is realized on a commercial Silicon wafer substrate by inductively
coupled plasma (ICP) etching. The key to this ultra-wideband absorption is
electromagnetic field tapering which exists due to the graded-index feature of
the structure (known as moth-eye effect), along with the ideal optical
properties of Mn which makes it an excellent metal for broadband absorption
applications. A full experimental characterization of the fabricated samples is
presented along with the physical analysis of the phenomena. The findings of
this paper can be used for the realization of lithography-free, cost-effective
and high-throughput mass production of broadband absorbers.

18
The categories of this paper are: econ
19
The categories of this paper are: eess
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph