Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Composite Reflective/Absorptive IR-Blocking Filters Embedded in
  Metamaterial Antireflection Coated Silicon   Infrared (IR) blocking filters are crucial for controlling the radiative
loading on cryogenic systems and for optimizing the sensitivity of bolometric
detectors in the far-IR. We present a new IR filter approach based on a
combination of patterned frequency selective structures on silicon and a thin
(50 $\mu \textrm{m}$ thick) absorptive composite based on powdered reststrahlen
absorbing materials. For a 300 K blackbody, this combination reflects
$\sim$50\% of the incoming light and blocks \textgreater 99.8\% of the total
power with negligible thermal gradients and excellent low frequency
transmission. This allows for a reduction in the IR thermal loading to
negligible levels in a single cold filter. These composite filters are
fabricated on silicon substrates which provide excellent thermal transport
laterally through the filter and ensure that the entire area of the absorptive
filter stays near the bath temperature. A metamaterial antireflection coating
cut into these substrates reduces in-band reflections to below 1\%, and the
in-band absorption of the powder mix is below 1\% for signal bands below 750
GHz. This type of filter can be directly incorporated into silicon refractive
optical elements.

15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org