  Levitated optomechanics, a rapidly expanding field that employs light to
monitor and manipulate the mechanical motion of levitated objects, is
increasingly relevant across physics, engineering, and other fields. This
technique, which involves levitating micro- and nano-scale objects in a vacuum
where they exhibit high-quality motion, provides an essential platform for
precision measurements. Noted for their ultra-high sensitivity, levitated
particles hold potential for a wide range of real-world applications. This
perspective article briefly introduces the principle of optical levitation and
the dynamics of levitated particles. It then reviews the emerging applications
of levitated particles in ultrasensitive force and torque measurements,
acceleration and rotation sensing, electric and magnetic field detection,
scanning probe microscopy, localized vacuum pressure gauging, acoustic
transduction, and chemical and biological sensing. Moreover, we discuss the
present challenges and explore opportunities to minimize and integrate
levitation systems for broader applications. We also briefly review
optomechanics with ion traps and magnetic traps which can levitate particles in
high vacuum without laser heating.
