The exploration of quantum-inspired symmetries in optical systems has spawned promising physics and provided fertile ground for developing devices exhibiting exotic functionalities. Founded on the anti-parity-time (APT) symmetry that is enabled by both spatial and temporal interplay between gain and loss, we demonstrate theoretically and numerically bi-color lasing in a single micro-ring resonator with spatiotemporal modulation along its azimuthal direction. In contrast to conventional multi-mode lasers that have mixed-frequency output, our laser exhibits stable, demultiplexed, tunable bi-color emission at different output ports. Our APT-symmetry-based laser may point out a new route for realizing compact on-chip coherent multi-color light sources.
We study the parity-symmetry-breaking quantum phase transition (QPT) in a cavity magnonic system driven by a parametric field, where the magnons in a ferrimagnetic yttrium-iron-garnet sphere strongly couple to a microwave cavity. With appropriate parameters, this cavity magnonic system can exhibit a rich phase diagram, including the parity-symmetric phase, parity-symmetry-broken phase, and bistable phase. When increasing the drive strength beyond a critical threshold, the cavity magnonic system undergoes either a first- or second-order nonequilibrium QPT from the parity-symmetric phase with mi…
We investigate the parity of transmission spectra in a photonic crystal (PhC) waveguide with a side-coupled cavity and a partially blocking element. We demonstrate, by means of numerical calculations, that by varying the cavity-block distance the spectra vary from being asymmetric with blue parity, to being symmetric (Lorentzian), to being asymmetric with red parity. For cavity-block distances larger than five PhC lattice constants, we show that the transmission spectrum is accurately described as the transmission spectrum of a Fabry-Perot etalon with a single propagating Bloch mode, and that …
In this paper, we proposed and numerically demonstrated a giant enhancement up to 108 in both forward and backward propagation of the Second Harmonic Generation by combining the high-quality factor cavities of the Bound States in the Continuum and the excellent nonlinear optical crystal of lithium niobate. The enhancement factor is defined as the ratio of the second harmonic signal generated by the structure (lithium niobate membrane with Si grating) divided by the signal generated by lithium niobate membrane alone. Furthermore, a minimum interaction time of 350 ps is achieved despite the etch…
The main challenge in the recent demonstration of conventional magnon blockade is to increase the nonlinearity of the system especially in comparison with the dissipation channels. One can consider the Kerr nonlinearity through which magnon blockade in a cavity magnonic system is possible provided that the Kerr nonlinearity is much stronger than the cavity and magnonic mode dissipation rates. In the present contribution, we consider a PT-symmetric cavity magnonic system and study the effect of PT-symmetric phase on the magnon statistics and hence magnon blockade. We show that the PT-symmetric …
Nonreciprocal elements, such as isolators and circulators, play an important role in classical and quantum information processing. Recently, strong nonreciprocal effects have been experimentally demonstrated in cavity optomechanical systems. In these approaches, the bandwidth of the nonreciprocal photon transmission is limited by the mechanical resonator linewidth, which is arguably much smaller than the linewidths of the cavity modes in most electromechanical or optomechanical devices. In this work, we demonstrate broadband nonreciprocal photon transmission in the \emph{reversed-dissipation} …
Narrow linewidth laser(NLL) of high frequency stability and small form factor is essential to enable applications in long range sensing, quantum information and atomic clocks. Various high performance NLL have been demonstrated by Pound-Drever Hall(PDH) lock or self injection lock(SIL) of a seed laser to a vaccum-stabilized FP cavity of ultrahigh quality factor(Q). However they are often complicated lab setups due to the sophisticated stabilizing system and locking electronics. Here we report a compact NLL of 68mL volume, realized by SIL of a diode laser to a miniature FP cavity of 7.7x108 Q a…
Optically-coupled semiconductor laser arrays are described by coupled rate equations. The coupled mode equations and carrier densities are included in the analysis, which inherently incorporate the carrier-induced nonlinearities including spatial hole burning and amplitude-phase coupling. We solve the steady-state coupled rate equations and consider the cavity frequency detuning and the individual laser pump rates as the experimentally controlled variables. We show that the carrier-induced nonlinearities play a critical role in the mode control, and we identify gain contrast induced by cavity …
We demonstrate symmetry protected bundle emission in the cavity QED system under the ultrastrong coupling regime. Parity symmetry of Rabi model only permits the super-Rabi oscillations with periodic generation of even photons in cavity, which is realized by the laser driven flip of qubit and the parity conserved transitions induced by Rabi interaction. Combined with dissipation, only 2$n$-photon correlated emissions are allowed, and the corresponding purities are significantly enhanced by the parity symmetry, due to the almost perfect suppression of bundle emissions with odd correlated photons…
We demonstrate single transverse-mode operation of broad-area coupled waveguide lasers enabled by parity-time (PT) symmetry. The PT symmetric laser operates on coupled waveguide cavities with electrically tuned gain and loss. Such counterintuitive waveguide design enables PT symmetric breaking, causing unique mode selection and ultimately enabling single mode operation. By electrically tuning the loss in the loss region of the coupled waveguide cavity, several different PT-symmetric regimes are analyzed theoretically, and the corresponding PT symmetric phase transition is demonstrated experime…
We theoretically investigate the optical second-order sideband generation (OSSG) in an optical parity-time (PT) symmetric system, which consists of a passive cavity trapping the atomic ensemble and an active cavity. It is found that near the exceptional point (EP), the efficiency of the OSSG increases sharply not only for the blue probe-pump detuning resonant case but also for the red one. Using experimentally achievable parameters, we study the effect of the atomic ensemble on the efficiency of the OSSG. The numerical results show that the efficiency of the OSSG is 30% higher than that of the…
We propose and demonstrate a high performance four-wavelength erbium-doped fiber laser (EDFL), enabled by a figure-8 compound-ring-cavity (F8-CRC) filter for single-longitudinal-mode (SLM) selection and a polarization-managed four-channel filter (PM-FCF) for defining four lasing wavelengths. We introduce a novel methodology utilizing signal-flow graph combined with Mason's rule to analyze a CRC filter in general and apply it to obtain the important design parameters for the F8-CRC filter used in this paper. By combining the functions of the F8-CRC filter and the PM-FCF filter assisted by the e…
It remains a challenge to directly print three-dimensional arbitrary shapes that exhibit structural colors at the micrometer scale. Woodpile photonic crystals (WPCs) fabricated via two-photon lithography (TPL) are promising as building blocks to produce 3D geometries that generate structural colors due to their ability to exhibit either omnidirectional or anisotropic photonic stopbands. However, existing approaches have focused on achieving structural colors when illuminating WPCs from the top, which necessitates print resolutions beyond the limit of commercial TPL and/or post-processing techn…
Chi-3 micro resonators have enabled compact and portable frequency comb generation, but require sophisticated dispersion control. Here we demonstrate an alternative approach using a chi-2 sheet cavity, where the dispersion requirement is relaxed by cavity phase matching. 21.2 THz broadband comb generation is achieved with uniform line spacing of 133.0 GHz, despite a relatively large dispersion of 275.4 fs^2/mm around 1064nm. With 22.6 % high slope efficiency and 14.9 kW peak power handling, this chi-2 comb can be further stabilized for navigation, telecommunication, astronomy, and spectroscopy…
The ability to manipulate cavity resonant modes is of critical importance in laser physics and applications. By exploiting the parity time (PT) symmetry, we propose and experimentally realize a single-mode FP laser with improved output power and high-speed modulation have been demonstrated. The proposed PT symmetric laser consists of two coupled structurally identical FP resonators. The gain and loss in two FP resonators can be manipulated independently by changing the injection currents. In the PT symmetric FP laser, single-mode operation is accomplished by selectively breaking of PT symmetry…
Photons at telecom wavelength are the ideal choice for high density interconnects while solid state qubits in the microwave domain offer strong interactions for fast quantum logic. Here we present a general purpose, quantum-enabled interface between itinerant microwave and optical light. We use a pulsed electro-optic transducer at millikelvin temperatures to demonstrate nanosecond timescale control of the converted complex mode amplitude with an input added noise of $N^{oe}_\textrm{in} = 0.16^{+0.02}_{-0.01}$ ($N^{eo}_\textrm{in} = 1.11^{+0.15}_{-0.07}$) quanta for the microwave-to-optics (rev…
Optical cavities are a cornerstone of photonics. They are indispensable in lasers, optical filters, optical combs and clocks, in quantum physics, and have enabled the detection of gravitational waves. Cavities transmit light only at discrete resonant frequencies, which are well-separated in micro-structures. Despite attempts at the construction of `white-light cavities', the benefits accrued upon optically interacting with a cavity -- such as resonant field buildup -- have remained confined to narrow linewidths. Here, we demonstrate achromatic optical transmission through a planar Fabry-Perot …
The quantum harmonic oscillator with parity-time ($\mathcal{PT}$) symmetry, obtained from the ordinary (Hermitian) quantum harmonic oscillator by an imaginary displacement of the spatial coordinate, provides an important and exactly-solvable model to investigate non-Hermitian extension of the Ehrenfest theorem. Here it is shown that transverse light dynamics in an optical resonator with off-axis longitudinal pumping can emulate a $\mathcal{PT}$-symmetric quantum harmonic oscillator, providing an experimentally accessible system to investigate non-Hermitian coherent state propagation.
The field of micro-cavity based frequency combs, or 'micro-combs'[1,2], has recently witnessed many fundamental breakthroughs[3-19] enabled by the discovery of temporal cavity-solitons, self-localised waves sustained by a background of radiation usually containing 95% of the total power[20]. Simple methods for their efficient generation and control are currently researched to finally establish micro-combs as out-of-the-lab widespread tools[21]. Here we demonstrate micro-comb laser cavity-solitons, an intrinsically highly-efficient, background free class of solitary waves. Laser cavity-solitons…
To date, micro- and nano-scale optomechanical systems have enabled many proof-of-principle quantum operations through access to high-frequency (GHz) phonon modes that are readily cooled to their thermal ground state. However, minuscule amounts of absorbed light produce excessive heating that can jeopardize robust ground state operation within such microstructures. In contrast, we demonstrate an alternative strategy for accessing high-frequency ($13$ GHz) phonons within macroscopic systems (cm-scale). Counterintuitively, we show that these macroscopic systems, with motional masses that are $>20…
Two-dimensional hexagonal boron nitride (hBN) has been known to host a variety of quantum emitters with properties suitable for a broad range of quantum photonic applications. Among them, the negatively charged boron vacancy (VB-) defect with optically addressable spin states has emerged recently due to its potential use in quantum sensing. Compared to spin defects in bulk crystals, VB- preserves its spin coherence properties when placed at nanometer-scale distances from the hBN surface, enabling nanometer-scale quantum sensing. On the other hand, the low quantum efficiency of VB- has hindered…
Noise-Limited Sensitivity in Cavity Optomechanical Molecular Sensing Enabled by Quantum Zero-Point Displacement Coupling and Strong Photon-Phonon Interaction for Chiral Detection
Phonon lasers, as the counterpart of photonic lasers, have been intensively studied in a large variety of systems, however, (all) most of them are based on the directly coherent pumping. Intuitively, dissipation is an unfavorable factor for gain in a laser. Here we demonstrate a novel mechanism of phonon lasing from the dissipative coupling in a multimode optomechanical system. By precisely engineering the dissipations of two membranes and tuning the intensity modulation of the cavity light, the two-membrane-in-the-middle system shows anti-parity-time (anti-PT) symmetry and the cavity mediated…
Random lasers are promising in the spectral regime, wherein conventional lasers are unavailable, with advantages of low fabrication costs and applicability of diverse gain materials. However, their practical application is hindered by high threshold powers, low power efficiency, and difficulties in light collection. Here, we demonstrate a power-efficient easy-to-fabricate non-resonant laser using a deep hole on a porous gain material. The laser action in this counterintuitive cavity was enabled by nonresonant feedback from strong diffuse reflections on the inner surface. Additionally, signific…
We present an all-fiber emitter-cavity quantum electrodynamics (QED) system which consists of two two-level emitters and a nanofiber cavity. Our scheme makes it possible to observe the higher-order exceptional points based on the coupling between the emitters and the nanofiber cavity. The effective gain of this cavity can be obtained by weakly driven to the nanofiber cavity via two identical laser fields, which will realize coherent perfect absorption (CPA) in the implementation of the experiments. Under the experimental feasible parameters, the Hamiltonian of this system is in the condition o…
The vertical-cavity surface-emitting lasers (VCSELs) have emerged as a vital approach for realizing energy efficient, high speed optical interconnects in the data center and supercomputers. As of today, VCSEL is the most suitable for mass production in terms of cost-effectiveness and reliability. However, there are still key challenges for higher speed modulation above 40 GHz. Here, a hexagonal transverse coupled cavity VCSEL adiabatically coupled through the center cavity is proposed. A 3-dB roll-off modulation bandwidth of 45 GHz is demonstrated, which is five times greater than a convention…
We report on the Doppler-free saturation spectroscopy of the nitrous oxide (N$_2$O) overtone transition at 1.28~$μ$m. This measurement is performed by the noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) technique based on the quantum-dot (QD) laser. A high intra-cavity power, up to 10~W, reaches the saturation limit of the overtone line using an optical cavity with a high finesse of 113,500. At a pressure of several mTorr, the saturation dip is observed with a full width at half-maximum of about 2~MHz and a signal-to-noise ratio of 71. To the best of our know…
Single-photon switches and transistors generate strong photon-photon interactions that are essential for quantum circuits and networks. However, to deterministically control an optical signal with a single photon requires strong interactions with a quantum memory, which have been lacking in a solid-state platform. We realize a single-photon switch and transistor enabled by a solid-state quantum memory. Our device consists of a semiconductor spin qubit strongly coupled to a nanophotonic cavity. The spin qubit enables a single gate photon to switch a signal field containing up to an average of 2…
Exceptional point (EP) associated with the parity-time (PT) symmetry breaking is receiving considerable recent attention by the broad physics community. By introducing balanced gain and loss, it has been realized in photonic, acoustic, and electronic structures. However, the observation of magnonic EP remains elusive. The major challenge is to experimentally generate the negative Gilbert damping, which was thought to be highly unlikely but is demanded by the PT symmetry. In this work, we study the magneto-optical interaction of circularly-polarized lasers with a submicron magnet placed in an o…
Hexagonal boron nitride (h-BN), a prevalent insulating crystal for dielectric and encapsulation layers in two-dimensional (2D) nanoelectronics and a structural material in 2D nanoelectromechanical systems (NEMS), has also rapidly emerged as a promising platform for quantum photonics with the recent discovery of optically active defect centers and associated spin states. Combined with measured emission characteristics, here we propose and numerically investigate the cavity quantum electrodynamics (cavity-QED) scheme incorporating these defect-enabled single photon emitters (SPEs) in h-BN microd…
