Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optomechanical response with nanometer resolution in the self-mixing
  signal of a terahertz quantum cascade laser   The effectiveness of self-mixing interferometry has been demonstrated across
the electromagnetic spectrum, from visible to microwave frequencies, in a
plethora of sensing applications, ranging from distance measurement to material
analysis, microscopy and coherent imaging. Owing to their intrinsic stability
to optical feedback, quantum cascade lasers (QCLs) represent a source that
offers unique and versatile characteristics to further improve the self-mixing
functionality at mid infrared and terahertz (THz) frequencies. Here, we show
the feasibility of detecting with nanometer precision deeply subwalength (<
{\lambda}/6000) mechanical vibrations of a suspended Si3N4-membrane used as the
external element of a THz QCL feedback interferometric apparatus. Besides
representing a platform for the characterization of small displacements, our
self-mixing configuration can be exploited for the realization of
optomechanical systems, where several laser sources can be linked together
through a common mechanical microresonator actuated by radiation pressure.

4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
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The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph