A liquid crystal elastomer actuator to move in a fluid is described herein. The actuator includes a body with dimensions between 100 nm and 800 μm having a low Reynolds number. The body includes a first and a second spatially separated volume, each comprising a liquid crystal elastomer. The first volume is doped with a first photoactive doping substance to absorb electromagnetic radiation at a first wavelength and the second volume is doped with a second photoactive doping substance to absorb electromagnetic radiation at a second wavelength. The first and second volumes change shape as a consequence of light absorption at the first or second wavelength, defining a first and a second joint. A first absorbance of the first volume at a given wavelength is different than a second absorbance of the second volume at a given wavelength, the first and second absorbance are measured in the same time interval.
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