Electro-optically spectrum narrowed, multiline intracavity optical parametric oscillators

Simultaneous electro-optic spectral switching and Q switching in a dual-wavelength Nd:YVO4 laser based on an aperiodic optical superlattice lithium niobate

We report the demonstration of an electro-optic (EO) switchable dual-wavelength (1064- and 1342-nm) Nd:YVO₄ laser based on an aperiodically poled lithium niobate (APPLN) chip whose domain structure is designed using aperiodic optical superlattice (AOS) technology. The APPLN works as a wavelength-dependent EO polarization-state controller in the polarization-dependent laser gain system to enable switching among multiple laser spectra simply by voltage control. When the APPLN device is driven by a voltage-pulse train modulating between a V_HQ (in which target laser lines obtain gain) and a V_LQ (in which laser lines are gain suppressed), the unique laser system can produce Q-switched laser pulses at dual wavelengths 1064 and 1342 nm, single wavelength 1064 nm, and single wavelength 1342 nm, as well as their non-phase-matched sum-frequency and second-harmonic generations at V_HQ= 0, 267, and 895 V, respectively. A laser can benefit from such a novel, to the best of our knowledge, simultaneous EO spectral switching and Q switching mechanisms to increase its processing speed and multiplexity for versatile applications.

Ultranarrow spectral line of the radiation in double qubit-cavity ultrastrong coupling system

The ultrastrongly coupling (USC) system has very important research significance in quantum simulation and quantum computing. In this paper, the ultranarrow spectrum of a circuit QED system with two qubits ultrastrongly coupled to a single-mode cavity is studied. In the regime of USC, the JC model breaks down and the counter-rotating terms in the quantum Rabi Hamiltonian leads to the level anti-crossing in the energy spectrum. Choosing a single-photon driving field at the point of avoided-level crossing, we can get an equivalent four-level dressed state model, in which the dissipation of the two intermediate states is only related to the qubits decay. Due to the electron shelving of these two metastable states, a narrow peak appears in the cavity emission spectrum. Furthermore, we find that the physical origin for the spectral narrowing is the vacuum-induced quantum interference between two transition pathways. And this interference effect couples the slowly decaying incoherent components of the density matrix into the equations of the sidebands. This result provides a possibility for the study of quantum interference effect in the USC system.

Electro-optically spectrum switchable, multiwavelength optical parametric oscillators based on aperiodically poled lithium niobate

We report the first fast switchable multiwavelength optical parametric oscillator based on aperiodic optical superlattice technology. The constructed aperiodically poled lithium niobate (APPLN) integrates the functionalities of two quasi-phase-matching devices on a chip to work simultaneously as an electro-optic (EO) switchable notch-like filter and a multiline optical parametric downconverter. When such an APPLN is built in a 1064-nm-pumped optical resonator system, we achieve the oscillation of dual signals at 1540 and 1550 nm, for a single signal at 1540 nm, and a single signal at 1550 nm in the system when the 3-cm-long APPLN is driven by 0 V, 354 V, and 805 V, respectively. The switching among the three signal spectra is operationally simple and electro-optically fast. The electro-optically switched signals also feature enhanced power spectral density due to the unique EO gain-spectrum filtering mechanism employed in this work.