The present application relates to optical-mechanical systems and methods for moving a solid object by applying conservation of angular momentum to a configuration of a laser light beam that emanates from the solid object. The system includes a rotatable housing and an axially movable laser light source coupled to the housing and configured to emit a first light beam along a first path. The system can include a first beam splitter disposed along the first path for splitting the first light beam into a second light beam and a third light beam. The system can cause the third light beam to travel in a closed path, as an approximation of a circular path of initial radius, and of decreasing radius. The system can further include a second beam splitter, axially movable first, second and third mirrors, and a third beam splitter disposed at one end of the housing.

A propulsion system for spacecraft is based on an electric engine that expels propellant to achieve thrust. The propellant is first ionized to generate a plasma. Plasma particles are selectively accelerated via a pulsed laser that accelerates predominantly the electrons in the plasma. The electrons are expelled first, forming a space charge that acts as a virtual cathode to accelerate the positive ions. Interactions between the laser beam and plasma electrons are predominantly through the ponderomotive force.

A propulsion system for spacecraft is based on an electric engine that expels propellant to achieve thrust. The propellant is first ionized to generate a plasma. Plasma particles are selectively accelerated via a pulsed laser that accelerates predominantly the electrons in the plasma. The electrons are expelled first, forming a space charge that acts as a virtual cathode to accelerate the positive ions. Interactions between the laser beam and plasma electrons are predominantly through the ponderomotive force.

A device for generating thrust using the dynamic Casimir effect comprising: an epitaxial stack of closely spaced parallel semiconductor laminae; and a voltage source; wherein each said semiconductor lamina is connected to said voltage source such that said voltage source can apply voltage to each semiconductor lamina.

A device for generating thrust using the dynamic Casimir effect comprising: an epitaxial stack of closely spaced parallel semiconductor laminae; and a voltage source; wherein each said semiconductor lamina is connected to said voltage source such that said voltage source can apply voltage to each semiconductor lamina.

A propulsion system for spacecraft is based on an electric engine that expels propellant to achieve thrust. The propellant is first ionized to generate a plasma. Plasma particles are selectively accelerated via a pulsed laser that accelerates predominantly the electrons in the plasma. The electrons are expelled first, forming a space charge that acts as a virtual cathode to accelerate the positive ions. Interactions between the laser beam and plasma electrons are predominantly through the ponderomotive force.

A propulsion system for spacecraft is based on an electric engine that expels propellant to achieve thrust. The propellant is first ionized to generate a plasma. Plasma particles are selectively accelerated via a pulsed laser that accelerates predominantly the electrons in the plasma. The electrons are expelled first, forming a space charge that acts as a virtual cathode to accelerate the positive ions. Interactions between the laser beam and plasma electrons are predominantly through the ponderomotive force.

Self-propelling, programmable nanoscopic motors capable of harvesting energy from absorbed photons and undergoing subsequent photoeletrochemical (PEC) reactions are provided. A nanomotor can have a three-dimensional Janus configuration and can sense the direction of a light source. By controlling the zeta potential of different parts of the nanomotor with chemical modifications, the nanomotor can be programmed to show either positive phototaxis or negative phototaxis.

Self-propelling, programmable nanoscopic motors capable of harvesting energy from absorbed photons and undergoing subsequent photoeletrochemical (PEC) reactions are provided. A nanomotor can have a three-dimensional Janus configuration and can sense the direction of a light source. By controlling the zeta potential of different parts of the nanomotor with chemical modifications, the nanomotor can be programmed to show either positive phototaxis or negative phototaxis.

Methods and systems are providing for generating relativistic motion of one or more nano particles. The methods include imposing a wave packet on the one or more nano particles by an electromagnetic field, the electromagnetic field including a vector potential AL perpendicular to the direction of the relativistic motion, where Aj_ is a function of an electron mass, an electron charge, a scalar potential summing a potential generated by nuclei of the one or more hydrogen atoms and an externally generated potential, and an electron velocity.