Optical 'Tractor Beam' for Space Applications

From Kepler’s comet observations to Maxwell’s theory of electromagnetism, there has long been a realisation that light can exert radiation pressure on an object. In recent years the invention of the laser has provided researchers with an intense source of light to further explore light-matter interactions, which has led to discovery of devices such as optical tweezers [1,2]. These devices take advantage of optical forces to trap and control the movement of microscopic particles. They are based on the principle of using a strongly focused laser beam to trap and move objects up to tens of micrometres, enabling new fundamental and applied physics research opportunities [3]. Through ongoing research into optical manipulation a number of research groups have looked into the idea of a negative optical pulling force, also known as a ‘tractor beam’. This force acts against the direction of propagation of light and is able to act on small particles through either controlling the electromagnetic field, the environment or the particles themselves [4].

Several theoretical and experimental approaches to create an optical pulling force have been undertaken. These methods include the use of optical conveyers [5,6], vortex beams [7,8], solenoid beams [9], enhancing the forward scattering of photons [10] and utilising the photophoretic force [11]. Recent progress has shown that it is possible to transport small particles against the propagation of light up to distances of 1 m using the photophoretic force [12]. This force makes use of the thermal effects induced by direct laser illumination and is a promising potential method for future long-range remote sampling and identification.

Project overview

The aim of this project is to investigate optical pulling forces in the context of space applications. This study will first look into methods to maximise the range of particle transport for planetary atmospheric conditions. This will then allow further assessment of optical pulling forces to aid existing remote sensing techniques for an integrated long-range particle detection and characterisation device.

References

1. A. Ashkin, “Acceleration and trapping of particles by radiation pressure,” Phys. Rev. Lett. 24, 156-159 (1970).
2. A. Ashkin, J. M. Dziedzic, J. E. Bjorkholm, S. Chu, “Observation of a single-beam gradient force optical trap for dielectric particles,” Opt. Lett. 11, 288-290 (1986).
3. D. Grier, “A revolution in optical manipulation,” Nature 424, 21-27 (2003).
4. A. Dogariu, S. Sukhov, J. J. Sáenz, “optically induced ‘negative forces’,” Nature Photonics 7, 24-27 (2012).
5. D. B. Ruffner, D. G. Grier, “Optical conveyers: A class of active tractor beams,” Phys. Rev. Lett. 109, 163903 (2012).
6. T. Čižmar, V. Garcés-Chávez, K. Dhokalia and P. Zemánek. “Optical conveyor belt for delivery of submicron objects,” Appl. Phys. Lett. 86, 174101 (2005).
7. A. Bahabad et al. “Particle trapping and conveying using an optical Archimedes’ screw,” Optica 5, 551-556 (2018).
8. V. G. Shvedov, A. V. Rode, Y. V. Izdebskaya, A. S. Desyatnikov, W. Krolikowski, and Y. S. Kivshar, “Giant optical manipulation,” Phys. Rev. Lett. 105, 118103 (2010).
9. S.-H. Lee, Y. Roichman, and D. G. Grier, “Optical solenoid beams,” Opt. Express 18, 6988–6993 (2010).
10. O. Brzobohatý, V. Karásek, M. Šiler, L. Chvátal, T. Čižmár, and P. Zemánek, “Experimental demonstration of optical transport, sorting and self-arrangement using a ‘tractor beam’,” Nat. Photonics 7, 123–127 (2013).
11. V. Shvedov, A. R. Davoyan, C. Hnatovsky, N. Engheta, and W. Krolikowski, “A long-range polarization-controlled optical tractor beam,” Nat. Photonics 8, 846–850 (2014).
12. J. Lin and Y.-Q. Li, “Optical trapping and rotation of airborne absorbing particles with a single focused laser beam,” Appl. Phys. Lett. 104, 101909 (2014).