Gradient traps

Figure 2.17 Traps for saaiple recovery from a gas chromatographic effluent. A, U-tube B, simple trap C, multiple temperature gradient trap D, Volmam trap.

Fig. 17. The optical gradient trap of Ashkin et al. (1986). Reprinted with permission from Ashkin, A., Dziedzic, J. M., Bjorkholm, J. E., and Chu, S., Optics Letters 11,288-290, Copyright 1986, The Optical Society of America.

A possible glimpse of the future is provided by Figure 8.12, which shows a schematic illustration of a magnetic-gradient trap for anti-atom spectroscopy. The scenario described below is due to Hansch and Zimmer-... 

We are currently working on two types of laser traps an alternating light beam trap [17], with modifications first mentioned by DaUbard and Phillips [19], and a six-beam gradient trap [16] in the optical molasses geometry. 

Figure 6 - Computer simulation of (a) ar ac trap and (b) a gradient trap with alternate cooling cycles. Heating due to photon scattering has been included. Induced dipole heating is not included.

Ashkin and Dziedzic (1987) gave an impressive demonstration of the optical trapping of dielectric particies in experiments with a biological particle (tobacco mosaic virus) in water by means of a single-beam gradient trap formed by an argon laser 0.1-0.3 W in power. The rodlike tobacco mosaic virus is 3000 nm long and 200 nm in diameter and has a refractive index of 1.57. In this experiment, Ashkin and Dziedzic... 

Fig. 13.2 Forces on a Mie-sized particle responsible for its axial (a, b) and transverse (c) displacement away from the focus fo in a single-beam gradient trap. The refraction of the rays a and b gives rise to the radiative pressure forces Fa and Fb- The net force F on the sphere is in all cases a restoring force back to the focus. (Reprinted with courtesy and permission of IEEE (USA) from Ashkin 2000.)...

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