We discuss a scheme that incorporates restricted spatial input location, orthogonal sort, and movement direction features, with particle sorting achieved by using an asymmetric potential cycled on and off, while movement is accomplished by photophoresis. Careful investigation has uncovered the odds of sorting between certain pairs of particle sizes to be solely dependent on radii in each phase of the process. This means that the most effective overall sorting can be achieved by maximizing the number of phases. This optimized approach is demonstrated using numerical simulation to permit grading of a range of nanometer-scale particle sizes.
© 2009 Optical Society of America
Lasers and Laser Optics
Original Manuscript: September 18, 2009
Manuscript Accepted: November 17, 2009
Published: December 4, 2009
Vol. 5, Iss. 1 Virtual Journal for Biomedical Optics
Adrian Neild, Tuck Wah Ng, and Timothy Woods, "Optimizing photophoresis and asymmetric force fields for grading of Brownian particles," Appl. Opt. 48, 6820-6826 (2009)