Nanoscale Lamb wave–driven motors in nonliquid environments

Abstract

Achieving light-driven motions in nonliquid environments presents formidable challenges, because microsized objects experience strong dry adhesion and intend to be stuck to contact surfaces with great tenacity. Here, in air and vacuum, we show rotary locomotion of a micrometer-sized metal plate with ~30 nm thickness, revolving around a microfiber. This motor is powered by pulsed light guided into the fiber as a coordinated consequence of an optically excited Lamb wave on the plate and favorable configuration of plate-fiber geometry. The motor, actuated by designed light pulses, crawls stepwise with subnanometer locomotion resolution. Furthermore, we can control the rotation velocity and step resolution by varying the repetition rate and pulse power, respectively. A light-actuated micromirror scanning with 0.001° resolution is then demonstrated on the basis of this motor. It offers unprecedented application potential for integrated micro-opto-electromechanical systems, outer-space all-optical precision mechanics and controls, and laser scanning for miniature lidar systems.

Plasmon-driven nanowire actuators for on-chip manipulation

“…5 ). Under special environmental conditions such as high vacuum (less than 10 −4 Pa) and low temperature (down to 30 K), such phenomena were still observed, indicating that the photophoretic force 25 , 27 , 28 induced by the surrounding gas molecules can be excluded. In addition, no recrystallization phenomena in as-driven Au nanowires were observed by using a high-resolution atomic force microscope (AFM) and a transmission electron microscopy (Supplementary Fig.…”

“…Currently, a common manipulation method in air environments is manually using 3D stage-actuated tungsten or silica probes to apply thrust on the nanowire sides 6,7,18,19 , but the nanowires can only be moved laterally with accuracy of ~1 μm. On the other hand, surface acoustic waves (SAWs) induced by the elastic expansion of metal lattices under transient heating of pulsed lasers [20][21][22] , have been used to drive microscale metal objects for surface cleaning, particle detaching, and microplate rotating [23][24][25] , thus providing the possibility of overcoming the strong surface adhesion to manipulate metal nanowires in non-liquid environments.…”

Robot-aided fN∙m torque sensing within an ultrawide dynamic range

“…When the characteristic length of a material is on the micro or nanoscale, particularly in micro/ nanoelectromechanical system (MEMS/NEMS), the scale effect becomes dominant and unavoidable in the analysis and design of materials and structural systems 1 . Therefore, a quantitative measurement of scale effects can help scientists comprehend the properties of micro/nanomaterials 2,3 and provide guidance for the topology design of various devices [4][5][6][7] . As a fundamental approach for smallscale material analytics 8 , the torsion test plays an indispensable role in promoting an understanding of the world at the micro/nanoscale.…”

Opto-thermoelectric pulling of light-absorbing particles

“…It is comprehensible that the photon-to-phonon energy transfer predominates at the illuminated side of light-absorbing objects. The key to pulling an object using photophoresis is to flip the thermal energy distribution, which requires a rigorous design for both the heating optics and the structures of the light-absorbing objects [11][12][13] . To date, pulling an object in free space using simple optics is still elusive, which hinders the development of the optical pulling force as a general manipulation technology.…”