We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)proc...We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.展开更多
Polarization control and modulation of optical signals play a crucial role in optical information transmission,with widespread applications in optical communication,sensing,and signal processing.Here,we propose an int...Polarization control and modulation of optical signals play a crucial role in optical information transmission,with widespread applications in optical communication,sensing,and signal processing.Here,we propose an intrinsically chiral nano-kirigami metasurface featuring out-of-plane twisting,which enables switchable spinselective light transmission.At the operating wavelength,it nearly completely blocks the transmission of one type of circularly polarized light while maintaining a transmission exceeding 70%for the other type.Crucially,by merely adjusting the rotation angles or deformation heights of the four arms of the nano-kirigami structures,the metasurface can switch from selective transmission of left-handed circularly polarized light to right-handed circularly polarized light,and vice versa,without the need for dramatic structural geometric chirality changes through mirror operations.Simultaneously,a remarkable circular dichroism of up to 0.74 is achieved,and its sign reverses with the transition of transmission.Electromagnetic multipolar analysis reveals that this switching of chiral response is governed by handedness-dependent excitations of toroidal dipole modes.Additionally,the spin-encoded near-field imaging results demonstrate the potential applications of this switchable spin-selective transmission based on nano-kirigami metasurfaces in digital imaging and chiroptical encryption.展开更多
基金Project supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202400624)the Natural Science Foundation of Chongqing CSTC(Grant No.CSTB2022NSCQBHX0020)+3 种基金the China Electronics Technology Group Corporation 44th Research Institute(Grant No.6310001-2)the Project Grant“Noninvasive Sensing Measurement based on Terahertz Technology”from Province and MOE Collaborative Innovation Centre for New Generation Information Networking and Terminalsthe Key Research Program of CQUPT on Interdisciplinary and Emerging Field(A2018-01)the Venture&Innovation Support program for Chongqing Overseas Returnees Year 2022。
文摘We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.
基金supported by the National Natural Science Foundation of China(Grant Nos.62205282 and 12074331)the Hebei Natural Science Foundation(Grant No.A2022203035)the Science and Technology Project of Hebei Education Department(Grant No.BJK2023009)。
文摘Polarization control and modulation of optical signals play a crucial role in optical information transmission,with widespread applications in optical communication,sensing,and signal processing.Here,we propose an intrinsically chiral nano-kirigami metasurface featuring out-of-plane twisting,which enables switchable spinselective light transmission.At the operating wavelength,it nearly completely blocks the transmission of one type of circularly polarized light while maintaining a transmission exceeding 70%for the other type.Crucially,by merely adjusting the rotation angles or deformation heights of the four arms of the nano-kirigami structures,the metasurface can switch from selective transmission of left-handed circularly polarized light to right-handed circularly polarized light,and vice versa,without the need for dramatic structural geometric chirality changes through mirror operations.Simultaneously,a remarkable circular dichroism of up to 0.74 is achieved,and its sign reverses with the transition of transmission.Electromagnetic multipolar analysis reveals that this switching of chiral response is governed by handedness-dependent excitations of toroidal dipole modes.Additionally,the spin-encoded near-field imaging results demonstrate the potential applications of this switchable spin-selective transmission based on nano-kirigami metasurfaces in digital imaging and chiroptical encryption.
