HK1077458A - Apparatus and method to generate and control optical traps to manipulate small particles - Google Patents

Description

Apparatus and method for generating and controlling optical traps to manipulate small particles

Background

Throughout this application, various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this invention pertains.

1. Field of the invention

The present invention generally relates to optical traps. In particular, the present invention relates to devices, systems, and methods for applying optical gradient forces to form multiple optical traps to manipulate small particles.

2. Discussion of related Art

Optical tweezers are an optical tool that uses the gradient force of a focused beam of light to manipulate particles with higher dielectric constants than the surrounding medium. To minimize its energy, such particles will move towards the region where the electric field is highest. In terms of momentum, the focused beam generates radiation pressure, and very little force is generated by the particles through absorption, reflection, diffraction, or refraction of light. The force generated by the radiation pressure is almost negligible, for example, a light source of a diode-pumped Nd: YAG laser operating at 10mW power generates only a few millinewtons of force. However, a force of a few milli-newtons is sufficient to manipulate small particles.

Other optical tools that may be used to manipulate small particles include, but are not limited to, optical vortices, optical bottles, optical rotators, and light cages. Although optical vortices are similar in use to optical tweezers, the principle of operation is different.

The optical vortex creates a gradient around the region of zero electric field, which is useful for manipulating particles with dielectric constants lower than the surrounding medium, reflective particles, or other types of particles that are repelled by optical tweezers. To minimize its energy, such particles will move towards the region of lowest electric field, i.e. the zero electric field region at the focus of the suitably shaped laser beam.

The optical vortex provides a region of zero electric field much like the hole in a toroid (an electron cyclotron chamber). The optical gradient is radial with the highest electric field around the toroid. The optical vortex traps small particles within the bore of the toroid. This prevention is achieved by the vortex sliding on the small particles along zero electric field lines.

An optical bottle differs from an optical vortex in that it has a zero electric field only at the focus, and a non-zero electric field at the end of the vortex. Optical bottles can be used to trap atoms and nanoatomic groups that are too small or too absorbent to be trapped with optical vortices or optical tweezers. See J.Arlt and M.J.Patett, in optical communications 25, 191-193, 2000, "Generation of a beam with a dark focus by areas of high intensity: the optical bottomlebeam ".

The optical rotator provides a spatial arm pattern that captures the target. Changing the pattern causes the captured target to rotate. See "Controlled rotation of optically tracked microscopic particles" by L.Paterson, M.P. MacDonald, J.Arlt, W.Sibbet, P.E.Bryant and K.Dholakia in science 292, 912, 914, 2001. Such tools may be used to manipulate non-spherical particles and drive MEMs devices or nanomachines.

The light cage is a macroscopic optical vortex-type device (Neal disclosed in U.S. patent No.5,939,716). The optical cage forms a time-averaged ring for the optical tweezers to surround particles that are too large or too reflective to be trapped with a dielectric constant lower than the surrounding medium. If the optical vortex is said to resemble a torus, the light cage resembles a jelly-filled torus. The colloidal toroid is the lower electric field region when the toroid aperture (for the vortex) is the region of zero electric field. In general, the gradient forces of the plurality of optical tweezers forming the toroid "push" particles with a lower dielectric constant than the surrounding medium towards the colloidal toroid, which may also be considered as the less bright region between the plurality of optical tweezers. However, unlike vortices, it forms a non-zero electric field region. Although optical vortices are similar in use to optical tweezers, the principle of operation is reversed.

It is known in the art to use a single laser with a diffractive optical element to form a plurality of focused diffracted laser beams to form an array of optical traps. U.S. patent No.6,055,106 to Grier and Dufresne discloses an optical trap array. The Grier and Dufresne patents propose the use of dynamic optical elements and focusing lenses to diffract the input beam and form an array of movable optical traps. An array of optical traps is formed at the back aperture beam diameter from a single input beam of suitable shape. Specifically, Gaussian TEM₀₀The input laser beam should have a beam diameter that substantially coincides with the back aperture diameter.

Gaussian TEM₀₀This limitation that the beam diameter of the input laser beam substantially coincides with the diameter of the back aperture can be seen in the cross-sectional view (FIG. 1), Gaussian TEM₀₀The beam has a lower intensity at the periphery. The resulting optical traps have similar strength cross sections.

Therefore, it is necessary to fill the back aperture with the input beam and to create optical traps with higher intensity at the periphery. The present invention fulfills these and other needs, and further provides related advantages.

Disclosure of Invention

The present invention provides a novel method and system to generate and control an optical trap array using gradient forces.

The present invention provides a novel and improved method, system and apparatus for generating, monitoring and controlling an array of optical traps. The optical traps can manipulate small particles independently or in concert.

The present invention employs a first phase patterning optical element to modify the phase distribution of an input beam of light or energy upstream of a second phase patterning optical element, which in turn diffracts the input beam (spread) into a plurality of beams.

By patterning the phase of the input beam with an upstream phase patterning optical element, the cross-section of the patterned input beam can be selected to have a substantially uniform intensity even near its periphery (fig. 2). A patterned input beam of substantially uniform intensity may be delivered to each beamlet. Thus, the plurality of beams produced by the second phase patterning optical element may have a beam width that coincides with the back aperture of the focusing lens and produces a plurality of optical traps having a higher intensity at the periphery than those formed by the unpatterned input beam having a lower intensity at the periphery.

To change the position of a given optical trap, the beam forming the optical trap can be steered to a new position only by the second phase patterning optical element, thereby changing the position of the resulting optical trap.

In other embodiments, the first and second phase patterning optical elements may work together to alter the position of a given optical trap by manipulating the beam forming the trap and thereby altering the position of the optical trap.

Selectively generating and controlling arrays of optical traps can be used in a variety of commercial applications such as optical circuit design and fabrication, nanocomposite construction, fabrication of electronic components, optoelectronics, chemical and biosensor arrays, holographic data storage matrix assemblies, rotating electrical machines, mid-or nano-sized pumping, energy sources or optical electrical machines to drive MEMS, facilitation of combinatorial chemistry, improvement of jelly self-assembly, manipulation of biological materials, examination of biological materials, concentration of selected biological materials, investigation of properties of biological materials, and testing of biological materials.

A beam splitter may be placed in the optical path to observe the activity of the optical trap array through the optical data stream (fig. 5). Filters may be added to restrict the passage of non-diffracted, scattered or reflected light along the path of the optical data stream and to reduce noise that may disturb the video or other surveillance effects of the optical data stream, thereby enhancing the viewing effect.

Additional features and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention, as set forth hereinafter in the detailed description, taken in conjunction with the accompanying drawings, wherein preferred embodiments of the invention are described and illustrated. The advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

Drawings

FIG. 1 is an intensity plot of an unmodified Gaussian beam cross-section;

FIG. 2 is an intensity plot of a modified Gaussian beam with a square cross-section;

FIG. 3 illustrates a preferred embodiment of a system for generating optical traps to manipulate small particles;

FIG. 4 illustrates a dual transmission embodiment of a system for generating optical traps to manipulate small particles;

FIG. 5 illustrates an embodiment of a system for creating optical traps to manipulate small particles with a transfer lens.

Description of The Preferred Embodiment

For convenience and reference, and not by way of limitation, certain terms will be used in the following description, which are simply defined as follows:

"beamlet" (beamlet) refers to a beamlet of focused light or other energy source produced by directing a focused beam of light or other energy source (e.g., formed by a laser or collimated output from a light emitting diode) through a medium that diffracts it into two or more beamlets. One example of a beamlet is a higher order laser beam diffracted from a grating.

"phase profile" refers to the phase of light or other energy source in a beam cross-section.

"phase patterning" refers to imparting a patterned phase shift to a focused beam of light, other energy source, or a beamlet that changes its phase pattern, including but not limited to phase modulation, mode formation, splitting, converging, diverging, shaping, and other manipulation of the focused beam or beamlet of other energy source.

A preferred embodiment of the present invention is for forming a plurality of movable optical traps, generally indicated by reference numeral 10 in fig. 1. A movable array of optical traps is formed by generating a focused beam of energy, such as electromagnetic energy. In the preferred embodiment, the electromagnetic waves are light waves, preferably having a wavelength from about 400nm to about 1060nm, with wavelengths in the green spectrum being particularly preferred. The beam forms collimated light, such as a collimated gaussian beam output by the laser beam 12, as shown in fig. 1.

The laser beam 12 is directed through a region "a" of a first phase patterning optical element 13, which first phase patterning optical element 13 is located upstream of a second phase patterning optical element 14 and at a plane 15 conjugate to a plane 17 at the back aperture 18 of a focusing lens 20. The preferred embodiment of the focusing lens 20 is an objective lens. The phase profile of the laser beam 12 is patterned by the first phase patterning optical element 13 to form a modified laser beam 22, which is directed to the second phase patterning optical element 14. The second phase patterning optical element 14 has a reflective variable surface medium 24 in which the modified laser beam 22 passes through a region "B" which is disposed substantially opposite the plane 17 of the back aperture 18.

Beamlets 26 and 28 are formed when modified laser beam 22 passes through second phase patterning optical element 14. When forming beamlets 26 and 28, the phase profile of each beamlet 26 and 28 is selected. The beamlets then pass through region "C" at back aperture 18 and are then converged by focusing lens 20 to form optical traps 1000 and 1002 within working focal region 2000 of conduit 2001. The conduit 2001, which is substantially comprised of a transparent material, allows the beamlets to pass through and not interfere with the formation of the optical traps.

The second phase patterning optical element may also cooperate with the focusing lens 20 to converge the beamlets. The beamlet has a beam diameter w substantially the same as the diameter of the back aperture 18. Varying the variable surface medium 24 of the second phase patterning optical element can selectively shape the phase profile of each beamlet.

The working focal region 2000 is the region where the medium comprising particles or other materials to be inspected, measured or manipulated by the optical traps 1000 and 1002 is placed.

For simplicity, only two optical traps 1000 and 1002 are shown, however, it should be understood that an array of such optical traps may be formed by the second phase patterning optical element 14.

Any suitable laser may be used as the light source for the laser beam 12. Useful lasers include solid state lasers, diode pumped lasers, gas lasers, dye lasers, amazonite (alexanderite) lasers, free electron lasers, VCSEL lasers, diode lasers, Ti-Sapphire lasers, doped YAG lasers, doped YLF lasers, diode pumped YAG lasers, flash lamp pumped YAG lasers. A diode pumped Nd: YAG laser operating preferably between 10mW and 5W.

The upstream or first phase patterning optical element serves to impart at least a square cross-section (fig. 2) to the wavefront of the laser beam 12 and results in a modified laser beam 22 having a substantially uniform square intensity cross-section. Thus, when the beam diameter w of the modified laser beam substantially coincides with the diameter of the back aperture 18, the peripheral intensity of the modified laser beam 22 is greater than the peripheral intensity of the input beam 12, and the respective optical traps 1000 and 1002 will have respective intensities at their peripheries. The first phase patterning optical element may also impart different selected wavefronts depending on the parameters of the system, which may include the strongest wavefront at the periphery.

In the embodiment shown in fig. 3-5, the type, number orientation, and position of each optical trap 1000 and 1002 can be selectively controlled by a hologram encoded on the variable surface medium 24 of the second phase patterning optical element 14, where the second phase patterning optical element 14 is used to shape the phase profile of the individual beamlets. The salient feature of the invention is that the motion of each optical trap, which can be rotated at a fixed position, rotated at an unsecured position, can be two-dimensional and three-dimensional, continuous and stepped. The control in this embodiment is achieved by changing at least the hologram formed on the surface medium 24 of the second phase patterning optical element 14.

Furthermore, depending on the type of optical trap desired, the phase patterning formed by the second phase patterning optical element 14 may include wavefront shaping, phase shifting, steering, diverging and converging to form different kinds of optical traps, including optical tweezers, optical vortices, optical bottles, optical rotators, optical cages and different kinds of combinations.

Suitable phase patterning optical elements are transmissive or reflective depending on how they direct the focused beam. As shown in fig. 3, 4 and 5, the transmissive phase patterning optical element allows the laser beam 12 to pass through, or in the case of fig. 4, allows the laser beam 12 and the correction laser beam 22 to pass through. As shown in fig. 3 and 5, the reflective phase patterning optical element reflects the modified laser beam 22. The upstream first phase patterning optical element, although illustrated as a transmissive element, may be replaced by a reflective element without departing from the scope of the invention.

In both general groups, the phase patterning optical element may be formed from a static or dynamic medium. Examples of suitable static phase patterning optical elements include diffractive optical elements having a fixed surface, such as gratings, including diffractive gratings, reflective gratings, transmissive gratings, holograms, stencils, light shaping holographic filters, polychromatic holograms, lenses, mirrors, prisms, waveplates, and the like.

The static phase patterning optical element may have different regions, each region being arranged to impart a different phase profile to the beamlets. In such an embodiment, the surface of the static phase patterning optical element may be altered by moving the surface relative to the laser beam to select a suitable region to alter the desired characteristics imparted to the beamlets, i.e. to alter the desired phase profile of at least one of the resulting beamlets.

Examples of suitable dynamic phase patterning optical elements whose function varies over time include: variable computer-generated diffraction patterns, variable phase-shifting materials, variable liquid crystal phase-shifting arrays, micro-mirror arrays, piston-type micro-mirror arrays, spatial light modulators, electro-optic deflectors, acousto-optic modulators, deformable mirrors, reflective MEMS arrays, and the like. The surface features may be encoded with dynamic phase patterning optical elements (e.g. to form a hologram as described above) or altered, e.g. by means of a computer, to effect a change in the hologram which may affect the number of beamlets, the phase pattern of at least one beamlet and the position of at least one beamlet.

Preferred dynamic phase patterning optical elements include phase-only spatial light modulators such as "PAL-SLM series X7665" manufactured by Hamamatsu, Japan or "SLM 512SA 7" and "SLM 512SA 15" manufactured by Boulder nonlinear systems Colorado Lafayette. These encodable phase patterning optical elements are computer controllable and versatile, so that they can generate beamlets 26 and 28 by diffracting modified laser beam 15 and selectively imparting a desired phase profile (characteristic) to the resulting beamlets.

Referring back to the embodiment shown in fig. 4, the laser beam 12 forms controllable optical traps 42 and 44 through an "a" region of a first phase patterning optical element 13, the first phase patterning optical element 13 being disposed substantially on a plane 46 opposite the plane 17 at the back aperture 18, through which the phase profile of the laser beam 12 is patterned to form a modified laser beam 22 that is directed to a second phase patterning optical element 48.

The second phase patterning optical element 48 has a transmissive variable surface medium 50 in which the modified laser beam 22 is transmitted through a region "B" disposed substantially at the opposite location of the plane 17 at the back aperture 18. Beamlets 52 and 54 are formed when modified laser beam 22 passes through second phase patterning optical element 48. As the beamlets form, the phase profile of each beamlet 52 and 54 is selected. The beamlets then pass through region "C" at the back aperture 18, are then converged by the focusing lens 20, and form the optical traps 42 and 44 in the working focal region 2000. The beam diameter "w" of the modified laser beam 22 substantially coincides with the diameter of the back aperture 18. The variable surface medium 50 of the second phase patterning optical element is varied to selectively shape the phase profile of each beamlet.

For simplicity, only two optical traps 42 and 44 are shown, but it will be appreciated that an array of such optical traps may be formed by the second phase patterning optical element.

The embodiment shown in fig. 5 uses additional transfer optics that can minimize the uncollimation of the beamlets in some cases. The pass optics are particularly useful when beamlets 62 and 64 are formed by a reflective second phase patterning optical element, or when a data stream is required to allow the activity of optical traps 66 and 68 to be observed behind a focusing lens.

A conventional telescopic system 70 is disposed between the second phase patterning optical element 14 and a beam splitter 72. The beam splitter 72 is constituted by a spectroscope, a photonic band gap mirror, a total reflection mirror, or other similar devices. The beam splitter 72 selectively reflects light of the wavelengths used to form the optical traps (beamlets 62 and 64) and transmits light of other wavelengths, such as imaging illumination light 74 provided by an illumination source 76 above the focusing lens 20. Then, part of the light reflected from the beam splitter 72 for forming the optical trap passes through the region "C" of the rear aperture 18 of the focusing lens 20.

The imaging illumination 74 passes through the working area 2000 along the optical axis of the focusing lens to form an optical data stream 78 corresponding to the phase distribution and position of one or more beamlets derived from the location and position of the small particles contained by the optical trap.

An optical filter element 80 (e.g., a polarizing element or a bandpass element) is disposed in the path of the optical data stream 78 to reduce the amount of reflected, scattered, or non-diffracted laser light passing along the axis of the optical data stream. The filter element 80 filters out one or more, and in some embodiments, all wavelengths of light except the preselected wavelength of the optical data stream 78.

The optical data stream 78 is then converted to a video signal so that the optical data stream 78 can be viewed, monitored, or analyzed by visual inspection, spectroscopy, and/or video surveillance by an operator. The optical data stream 78 may also be processed by a photodetector to monitor intensity, or by any suitable means to convert the optical data stream into a digital data stream suitable for use by a computer.

To capture small particles, the operator and/or computer will adjust the second phase patterning optical element 14 to direct the movement of each optical trap to obtain a selected small particle and capture it. Multiple optical traps containing small particles can then be constructed and reconfigured. Using the optical data stream, the position and characteristics of one or more captured small particles can be monitored by a camera, spectroscopy, or optical data stream, which provides information to a computer that controls the selection of the detector and the generation of the optical traps for use in adjusting the type of small particles contained by the optical traps. The motion may be tracked based on a predetermined motion of each optical trap resulting from encoding the phase patterning element. In addition, a computer may be used to maintain a record of each detector contained in each optical trap.

Additional features and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention, as set forth hereinafter in the detailed description, taken in conjunction with the accompanying drawings, wherein preferred embodiments of the invention are described and illustrated. The advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

Claims (60)

1. An apparatus for trapping small particles by forming an optical trap, comprising:

a first phase patterning optical element for receiving the laser beam and imparting a selected cross-section to a wavefront of the laser beam;

a second phase patterning optical element downstream of the first phase patterning optical element for receiving the laser beam and forming at least two beamlets; and

a focusing lens having a front aperture and a back aperture disposed downstream of the second phase patterning optical element; whereby the second phase patterning optical element in cooperation with the focusing lens can converge beamlets and establish gradient conditions, respectively, to form an optical trap capable of manipulating small particles.

2. The apparatus of claim 1, wherein the first phase patterning optical element is selected from the group consisting of transmissive and reflective phase patterning optical elements.

3. The apparatus of claim 2, wherein the first phase patterning optical element is selected from the group consisting of static and dynamic phase patterning optical elements.

4. The apparatus of claim 3, wherein the first phase patterning optical element is selected from the group consisting of a grating, a diffraction grating, a reflection grating, a transmission grating, a hologram, a stencil, a light shaping holographic filter, a polychromatic hologram, a lens, a mirror, a prism, and a wave plate.

5. The apparatus of claim 3, wherein the first phase patterning optical element is selected from the group consisting of a computer-generated variable diffraction pattern, a variable phase shifting material, a variable liquid crystal phase shifting array, a micromirror array, a piston mode micromirror array, a spatial light modulator, an electro-optic deflector, an acousto-optic modulator, a deformable mirror, and a reflective MEMS array.

6. The apparatus of claim 1, wherein the first and second phase patterning optical elements are selected from the group consisting of transmissive and reflective phase patterning optical elements.

7. The apparatus of claim 1 wherein the first and second phase patterning optical elements are selected from the group consisting of static and dynamic phase patterning optical elements.

8. The apparatus of claim 7, wherein at least one of the first and second phase patterning optical elements is selected from the group consisting of a grating, a diffraction grating, a reflection grating, a transmission grating, a hologram, a stencil, a light shaping holographic filter, a polychromatic hologram, a lens, a mirror, a prism, and a wave plate.

9. The apparatus of claim 7, wherein at least one of the first and second phase patterning optical elements is selected from the group consisting of a computer generated variable diffraction pattern, a variable phase shifting material, a variable liquid crystal phase shifting array, a micromirror array, a piston mode micromirror array, a spatial light modulator, an electro-optical deflector, an acousto-optical modulator, an anamorphic mirror, and a reflective MEMS array.

10. The apparatus of claim 3, wherein the first phase patterning optical element is a phase-only spatial light modulator.

11. The apparatus of claim 7 wherein at least one of the first and second phase patterning optical elements is a phase-only spatial light modulator.

12. The apparatus of claim 1, further comprising a device for generating a laser beam.

13. The apparatus of claim 12, wherein the laser beam generating device is selected from the group consisting of a solid state laser, a diode pumped laser, a gas laser, a dye laser, a Yamama laser, a free electron laser, a VCSEL laser, a diode laser, a titanium-sapphire laser, a doped YAG laser, a doped YLF laser, a diode pumped YAG laser, a flash lamp pumped YAG laser.

14. The apparatus of claim 1, wherein the focusing lens is an objective lens.

15. The apparatus of claim 1, further comprising a beam splitter disposed opposite the back aperture of the focusing lens, whereby the beamlets may be directed at the back aperture and the optical data stream may pass from the front aperture to the back aperture along the optical axis of the focusing lens.

16. The apparatus of claim 15, further comprising an optical filter selected from the group consisting of a polarizing element and a bandpass element disposed along the optical axis of the focusing lens and behind the beam splitter.

17. The apparatus of claim 1 further comprising at least one telescope lens system disposed between upstream of the focusing lens and downstream of the second phase patterning optical element.

18. The apparatus of claim 15, further comprising at least one telescope lens system disposed upstream of the beam splitter.

19. The apparatus of claim 15, further comprising at least one telescope lens system disposed downstream of the beam splitter.

20. The apparatus of claim 15, further comprising at least one telescope lens system disposed upstream and downstream of the beam splitter.

21. The apparatus of claim 1, wherein the selected cross-section is substantially square.

22. The apparatus of claim 1, wherein the selected cross-section has a high strength at the periphery.

23. A system for trapping small particles by forming a movable optical trap, comprising:

a phase patterning optical element for receiving the laser beam to impart a square cross section to a wavefront of the laser beam;

at least one computer;

a dynamic phase patterning optical element having a variable surface encoded with a hologram by a computer for receiving a laser beam from the phase patterning optical element; whereby a movable beamlet can be formed from the received laser beam; and

an objective lens having a front aperture and a back aperture disposed downstream of the dynamic phase patterning optical element; whereby the dynamic phase patterning optical element in cooperation with the objective lens separately converges beamlets and establishes gradient conditions to form an optical trap capable of manipulating small particles.

24. The system of claim 23, further comprising a device that generates a laser beam.

25. The system of claim 23, further comprising a beam splitter disposed opposite the back aperture of the objective lens, whereby the beamlets may be directed at the back aperture and the optical data stream may pass from the front aperture to the back aperture along the optical axis of the focusing lens.

26. The system of claim 23, further comprising means for converting the optical data stream into a digital data stream suitable for use with a computer.

27. The system of claim 23, further comprising at least one telescope lens system disposed upstream of the objective lens.

28. The system of claim 25, further comprising at least one telescope lens system disposed upstream of the beam splitter.

29. The system of claim 25, further comprising at least one telescope lens system disposed downstream of the beam splitter.

30. The system of claim 25, further comprising at least one telescope lens system disposed upstream and downstream of the beam splitter.

31. The system of claim 26, further comprising an illumination source.

32. The system of claim 23, wherein the selected cross-section is substantially square.

33. The system of claim 23, wherein the selected cross-section has a high strength at its periphery.

34. A method of capturing small particles, comprising:

generating a modified laser beam by imparting a square cross-section to a wavefront of the laser beam directed by the first phase patterning optical element;

generating at least two beamlets by directing the modified laser beam through a second phase patterning optical element;

directing the laser beam through a focusing lens to form an optical trap with a conduit;

providing at least two small particles; and

the small particles are contained in the optical trap.

35. The method of claim 34, wherein the selected cross-section is square.

36. The method of claim 35, wherein the selected cross-section has the strongest strength at its periphery.

37. A method of manipulating small particles with an optical trap, comprising:

generating a modified laser beam by imparting a selected cross-section to a wavefront of the laser beam directed by the first phase patterning optical element;

generating at least two beamlets by directing the modified laser beam through a second phase patterning optical element;

creating optical traps in a conduit by directing the beamlets through a focusing lens;

providing at least two small particles in the conduit; and

at least one small particle is contained in an optical trap.

38. The method of claim 37, further comprising changing a position of at least one optical trap.

39. The method of claim 37, wherein the optical trap is formed by two or more optical tweezers, optical vortices, optical bottles, optical rotators, or light cages.

40. The method of claim 37, wherein the selected cross-section is square.

41. The method of claim 37, wherein the selected cross-section has the strongest strength at its periphery.

42. The method of claim 37, wherein each optical trap is independently movable.

43. The method of claim 37 wherein the movement of each optical trap is computer controlled.

44. The method of claim 37 wherein the movement of each optical trap is computer controlled.

45. A method of manipulating small particles with an optical trap, comprising:

generating a modified laser beam by imparting a selected cross-section to a wavefront of the laser beam directed by the first phase patterning optical element;

generating at least two beamlets by directing the modified laser beam through a second phase patterning optical element;

providing an optical data stream;

creating optical traps in a conduit by directing the beamlets through a focusing lens;

providing at least two small particles within the conduit; and

at least one small particle is contained within an optical trap.

46. The method of claim 45 wherein the movement of each optical trap is computer controlled.

47. The method of claim 45, further comprising receiving the optical data stream with a computer.

48. The method of claim 46, further comprising analyzing the optical data stream with a computer.

49. The method of claim 46, wherein the computer directs the movement of the at least one optical trap based on an analysis of the optical data stream.

50. The method of claim 45, further comprising converting the optical data stream to a video signal.

51. The method of claim 50, further comprising receiving the video signal with a computer.

52. The method of claim 51, further comprising analyzing the video signal with a computer.

53. The method of claim 51, further comprising directing movement of one or more optical traps with the computer based on analysis of the video signal.

54. A method as in claim 50 wherein the video signal is used to generate an image.

55. The method of claim 54, further comprising an operator viewing the image and directing movement of the one or more optical traps based on the viewing of the image.

56. The method of claim 45, wherein the optical data stream is spectral data.

57. The method of claim 56, further comprising directing movement of one or more optical traps with a computer based on analysis of the spectral data.

58. The method of claim 45, wherein the optical trap is formed by two or more optical tweezers, optical vortices, optical bottles, optical rotators, or light cages.

59. The method of claim 45, wherein the selected cross-section has a high strength at its periphery.

60. The method of claim 36, wherein the selected cross-section has the strongest strength at its periphery.