Nanostructured dielectric metasurfaces offer unprecedented opportunities to control light-matter momentum exchange,and thereby the forces and torques that light can exert on matter.Here we introduce optical metasurfac...Nanostructured dielectric metasurfaces offer unprecedented opportunities to control light-matter momentum exchange,and thereby the forces and torques that light can exert on matter.Here we introduce optical metasurfaces as components of ultracompact untethered microscopic metaspinners capable of efficient light-induced rotation in a liquid environment.Iluminated by weakly focused light,a metaspinner generates torque via photon recoil through the metasurfaces'ability to bend light towards high angles despite their sub-wavelength thickness,thereby creating orbital angular momentum.We find that a metaspinner is subject to an anomalous transverse lateral optical gradient force that acts in concert with the classical gradient force.Consequently,when two or more metaspinners are trapped together in a laser beam,they collectively orbit the optical axis in the opposite direction to their spinning motion,in stark contrast to rotors coupled through hydrodynamic or mechanical interactions.The metaspinners delineated herein not only serve to llustrate the vast possibilities of utilizing optical metasurfaces for fundamental exploration of optical torques,but they also represent potential building-blocks of artificial active matter systems,light-driven micromachinery,and general-purpose optomechanical devices.展开更多
Hollow-core fiber(HCF)is a special optical waveguide type that can guide light in the air or liquid core surrounded by properly designed cladding structures.The guiding modes of the fiber can generate sufficient optic...Hollow-core fiber(HCF)is a special optical waveguide type that can guide light in the air or liquid core surrounded by properly designed cladding structures.The guiding modes of the fiber can generate sufficient optical gradient forces to balance the gravity of the particles or confine the atom clouds,forming a stable optical trap in the hollow core.The levitated objects can be propelled over the fiber length along the beam axis through an imbalance of the optical scattering forces or by forming an optical lattice by the counter-propagating beams.The ability to overcome the diffraction of the laser beam in HCF can significantly increase the range of the optical manipulation compared with standard free-space optical tweezers,opening up vast ranges of applications that require long-distance optical control.Since the first demonstration of optical trapping in HCF,hollow-core-fiber-based optical trap(HCF-OT)has become an essential branch of optical tweezer that draws intense research interests.Fast progress on the fundamental principle and applied aspects of HCF-OT has been visible over the past two decades.In recent years,significant milestones in reducing the propagation loss of HCF have been achieved,making HCF an attractive topic in the field of optics and photonics.This further promotes the research and applications of HCF-OT.This review starts from the mechanism of light guidance of HCF,mainly focusing on the issues related to the optical trap in the hollow core.The basic principles and key features of HCF-OT,from optical levitation to manipulation and the detection of macroscopic particles and atoms,are summarized in detail.The key applications of HCF-OT,the challenges and future directions of the technique are also discussed.展开更多
In this paper, we propose an on-chip all optical transistor driven by optical gradient force. The transistor consists of a single micro-ring resonator, half of which is suspended from the substrate, and a bus waveguid...In this paper, we propose an on-chip all optical transistor driven by optical gradient force. The transistor consists of a single micro-ring resonator, half of which is suspended from the substrate, and a bus waveguide. The free-standing arc is bent by optical gradient force generated when the control light is coupled into the ring. The output power of the probe light is tuned continuously as the transmission spectrum red-shift due to the displacement of the free-standing arc. The transistor shows three working regions known as cutoff region, amplified region and saturate region, and the characteristic curve is tunable by changing the wavelength of the control light. Potential applications of the all optical transistor include waveform regeneration and other optical computing.展开更多
基金Open access funding provided by Chalmers University of Technology.
文摘Nanostructured dielectric metasurfaces offer unprecedented opportunities to control light-matter momentum exchange,and thereby the forces and torques that light can exert on matter.Here we introduce optical metasurfaces as components of ultracompact untethered microscopic metaspinners capable of efficient light-induced rotation in a liquid environment.Iluminated by weakly focused light,a metaspinner generates torque via photon recoil through the metasurfaces'ability to bend light towards high angles despite their sub-wavelength thickness,thereby creating orbital angular momentum.We find that a metaspinner is subject to an anomalous transverse lateral optical gradient force that acts in concert with the classical gradient force.Consequently,when two or more metaspinners are trapped together in a laser beam,they collectively orbit the optical axis in the opposite direction to their spinning motion,in stark contrast to rotors coupled through hydrodynamic or mechanical interactions.The metaspinners delineated herein not only serve to llustrate the vast possibilities of utilizing optical metasurfaces for fundamental exploration of optical torques,but they also represent potential building-blocks of artificial active matter systems,light-driven micromachinery,and general-purpose optomechanical devices.
基金supported by the National Key Research and Development Program of China(2023YFC3010001)National Natural Science Foundation of China(62275021,62450075,W2412086,62175044,12404315)+1 种基金Beijing Natural Science Foundation(4232078)Science and Technology Innovation Program of Beijing Institute of Technology Teli Students’Science and Technology Innovation Team Project(2024CX06101).
文摘Hollow-core fiber(HCF)is a special optical waveguide type that can guide light in the air or liquid core surrounded by properly designed cladding structures.The guiding modes of the fiber can generate sufficient optical gradient forces to balance the gravity of the particles or confine the atom clouds,forming a stable optical trap in the hollow core.The levitated objects can be propelled over the fiber length along the beam axis through an imbalance of the optical scattering forces or by forming an optical lattice by the counter-propagating beams.The ability to overcome the diffraction of the laser beam in HCF can significantly increase the range of the optical manipulation compared with standard free-space optical tweezers,opening up vast ranges of applications that require long-distance optical control.Since the first demonstration of optical trapping in HCF,hollow-core-fiber-based optical trap(HCF-OT)has become an essential branch of optical tweezer that draws intense research interests.Fast progress on the fundamental principle and applied aspects of HCF-OT has been visible over the past two decades.In recent years,significant milestones in reducing the propagation loss of HCF have been achieved,making HCF an attractive topic in the field of optics and photonics.This further promotes the research and applications of HCF-OT.This review starts from the mechanism of light guidance of HCF,mainly focusing on the issues related to the optical trap in the hollow core.The basic principles and key features of HCF-OT,from optical levitation to manipulation and the detection of macroscopic particles and atoms,are summarized in detail.The key applications of HCF-OT,the challenges and future directions of the technique are also discussed.
基金Acknowledgements This work was partially supported by the Program for New Century Excellent Talents in Ministry of Education of China （No. NCET-11-0168）, and the National Natural Science Foundation of China （Grant Nos. 11174096 and 61475052）.
文摘In this paper, we propose an on-chip all optical transistor driven by optical gradient force. The transistor consists of a single micro-ring resonator, half of which is suspended from the substrate, and a bus waveguide. The free-standing arc is bent by optical gradient force generated when the control light is coupled into the ring. The output power of the probe light is tuned continuously as the transmission spectrum red-shift due to the displacement of the free-standing arc. The transistor shows three working regions known as cutoff region, amplified region and saturate region, and the characteristic curve is tunable by changing the wavelength of the control light. Potential applications of the all optical transistor include waveform regeneration and other optical computing.
