High-sensitivity force sensing using a phonon laser in an active levitated optomechanical system.

Force detection with high sensitivity is of paramount importance in many fields of study, from gravitational wave detection to investigations of surface forces. Here, we propose and demonstrate a force-sensing method based on gain-enhanced nonlinearity in a nonlinear phonon laser. Experimental and simulation results show that the input force leads to the frequency shift of phonon laser, due to nonlinearity.

Structured-light displacement detection method using split-waveplate for dual-beam optical tweezers.

Structured-light displacement detection method is an innovative approach with extremely high sensitivity for measuring the displacement of a levitated particle. This scheme includes two key components, a split-waveplate (SWP) and a single-mode fiber. In this work, we further investigated the influence of SWP installation on this method regarding the sensitivity of displacement detection.

Characteristics of the phonon laser in the active levitated optomechanical system.

Phonon lasers, coherent oscillations of phonons, have gradually become one of the emerging frontiers in the last decades, and have promising applications in quantum sensing, information processing, and precise measurement. Recently, phonon lasers based on dissipative coupling have been realized in an active levitated optomechanical (LOM) system for the first time. Here, we further investigated the characteristics of the phonon laser in the system above regarding the oscillator amplitude and the phonon laser linewidth.

Enhanced optical trapping of ZrO@TiO photonic force probe with broadened solvent compatibility.

Optical trapping and manipulating nanoparticles are essential tools for interrogating biomedicine at the limits of space and time. Typically, silica or polystyrene microspheres are used as photonic force probes. However, adapting those probes to organic solvents is an ongoing challenge due to the limited solvent compatibility and low refractive index mismatch.

Differential displacement measurement of the levitated particle using D-shaped mirrors in the optical tweezers.

Displacement measurement using a D-shaped mirror is a key technology in optical tweezers, which have emerged as an important tool for precision measurement. In this paper, we first study the influences of installation errors for the D-shaped mirror on the displacement measurement. The calibration factor and sensitivity of the different installation parameters are quantified.

Customizable trajectory of trapped particle in quadruple-beam optical trap.

We have presented and demonstrated a customizable trajectory of a trapped particle in the Quadruple-beam optical trap. The orbital motion of the trapped microsphere was realized by modulating the trapping power. The motion trajectories could be designed by adjusting the modulation frequency, amplitude, and phase.

Optical Pulling Using Chiral Metalens as a Photonic Probe.

Optical pulling forces, which can pull objects in the source direction, have emerged as an intensively explored field in recent years. Conventionally, optical pulling forces exerted on objects can be achieved by tailoring the properties of an electromagnetic field, the surrounding environment, or the particles themselves. Recently, the idea of applying conventional lenses or prisms as photonic probes has been proposed to realize an optical pulling force.

Self-feedback induced bistability in dual-beam intracavity optical tweezers.

The intracavity optical tweezers is a new, to the best of our knowledge, cavity optomechanics system, implementing a self-feedback control of the particle's position by trapping the particle inside an active ring cavity. This self-feedback mechanism efficiently constructs a novel potential in the cavity. Here we predict and give experimental evidence for the self-feedback induced optical bistability in dual-beam intracavity optical tweezers.

Dual-beam intracavity optical tweezers with all-optical independent axial and radial self-feedback control schemes.

The feedback control to optical tweezers is an obvious approach to improve the optical confinement. However, the electronic-based feedback controlling system in optical tweezers usually consists of complex software and hardware, and its performance is limited by the inevitable noise and time-delay from detecting and controlling devices. Here, we present and demonstrate the dual-beam intracavity optical tweezers enabling all-optical independent radial and axial self-feedback control of the trapped particle's radial and axial motions.

Optical confinement efficiency in the single beam intracavity optical tweezers.

Single beam intracavity optical tweezers characterizes a novel optical trapping scheme where the laser operation is nonlinearly coupled to the motion of the trapped particle. Here, we first present and establish a physical model from a completely new perspective to describe this coupling mechanism, using transfer matrices to calculate the loss of the free-space optical path and then extracting the scattering loss that caused by the 3D motions of the particle. Based on this model, we discuss the equilibrium position in the single beam intracavity optical tweezers.

Coupling between axial and radial motions of microscopic particle trapped in the intracavity optical tweezers.

Intracavity optical tweezers have been proposed and demonstrated recently, which allows orders-of-magnitude higher optical confinement with lower-numerical-aperture lens and lower laser power in contrast to the standard optical tweezers. We further investigate its characteristics about the position stability of trapped particles. The dependence of the radial and axial position stability on the laser intensity acting on the particle of 10-µm diameter in intracavity optical tweezers and standard optical tweezers are compared experimentally.

All-fiber interferometer for displacement and velocity measurement of a levitated particle in fiber-optic traps.

We propose an all-fiber interferometer based on laser Doppler velocimetry in a dual-beam fiber-optic trap to measure the displacement and velocity of a trapped particle. ABCD matrices are used to compute the contrast ratio of the interference. The influence of the reflectivity of the fiber end face is discussed.

Back-focal-plane displacement detection using side-scattered light in dual-beam fiber-optic traps.

In optical traps the position of a trapped bead is usually determined by measuring the intensity distribution of the forward-scattered light and the back-scattered light. In this paper we demonstrate that this position can be determined using the side-scattered light. A quadrant photodiode is used to monitor the position of an optically trapped object in a dual-beam fiber-optic trap by measurement of intensity shifts in the back focal plane of the objective that is perpendicular to the propagating beam.

Optically bound colloidal lattices in evanescent optical fields.

In this Letter, we demonstrate the formation of a stable two-dimensional lattice of colloidal particles in the interference pattern formed by four evanescent optical fields at a dielectric interface. The microspheres are observed to form a two-dimensional square lattice with lattice vectors inclined relative to the beam propagation directions. We use digital video microscopy and particle tracking to measure the Brownian motion of particles bound in the lattice, and use this to characterize fluctuations in the local ordering of particles using the bond orientational order parameter, the probability distribution of which is shown to be a chi-squared distribution.

Characteristics of the orbital rotation in dual-beam fiber-optic trap with transverse offset.

The orbital rotation is an important type of motion of trapped particles apart from translation and spin rotation. It could be realized by introducing a transverse offset to the dual-beam fiber-optic trap. The characteristics (e.

Dynamics analysis of microsphere in a dual-beam fiber-optic trap with transverse offset.

A comprehensive dynamics analysis of microsphere has been presented in a dual-beam fiber-optic trap with transverse offset. As the offset distance between two counterpropagating beams increases, the motion type of the microsphere starts with capture, then spiral motion, then orbital rotation, and ends with escape. We analyze the transformation process and mechanism of the four motion types based on ray optics approximation.

Theoretical analysis on the rotation-induced frequency difference in ring lasers with coupled cavities.

We analyzed the effective scale factor of ring laser gyros with coupled cavities in a general way. The coupled cavities can be made of both an odd and even number of mirrors, or even fiber coil. Compared with the "zero-vector-area" design in previous publications, we use the propagation loss rather than transmittance and reflectivity of mirrors to characterize the coupled cavities, which are more universal and controllable.

Temperature compensation method using readout signals of ring laser gyroscope.

Traditional compensation methods using temperature-related parameters have little effect when the ring laser gyroscope (RLG) bias changes rapidly. To solve this problem, a novel RLG bias temperature compensation method using readout signals is proposed in this paper. Combined with the least squares support vector machine (LS-SVM) algorithm, the novel method can improve the precision of the RLG bias.