Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optomechanical measurement of photon spin angular momentum and optical
  torque in integrated photonic devices   Photons carry linear momentum, and spin angular momentum when circularly or
elliptically polarized. During light-matter interaction, transfer of linear
momentum leads to optical forces, while angular momentum transfer induces
optical torque. Optical forces including radiation pressure and gradient forces
have long been utilized in optical tweezers and laser cooling. In nanophotonic
devices optical forces can be significantly enhanced, leading to unprecedented
optomechanical effects in both classical and quantum regimes. In contrast, to
date, the angular momentum of light and the optical torque effect remain
unexplored in integrated photonics. Here, we demonstrate the measurement of the
spin angular momentum of photons propagating in a birefringent waveguide and
the use of optical torque to actuate rotational motion of an optomechanical
device. We show that the sign and magnitude of the optical torque are
determined by the photon polarization states that are synthesized on the chip.
Our study reveals the mechanical effect of photon's polarization degree of
freedom and demonstrates its control in integrated photonic devices. Exploiting
optical torque and optomechanical interaction with photon angular momentum can
lead to torsional cavity optomechanics and optomechanical photon spin-orbit
coupling, as well as applications such as optomechanical gyroscope and
torsional magnetometry.

0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom