# Patent

## Title
Controlling microparticles through a light field having controllable intensity and periodicity of maxima thereof

## Abstract

A method includes providing a capability to control divergence of a coherent light beam having an axially symmetrical distribution of intensity thereof through an optical divergence controller, and directing an output of the optical divergence controller related to the controlled divergence of the coherent light beam onto a glass prism. The glass prism includes a planar shape onto which a pyramidal structure is formed. The method also includes controlling a distance between maxima of an output light field of the glass prism and intensity thereof through controlling the divergence of the coherent light beam through the optical divergence controller and/or varying a distance between the optical divergence controller and the glass prism, and utilizing the output light field of the glass prism in controlling microparticles in a microtechnology or a nanotechnology application.

## Background
CLAIM OF PRIORITY
This patent application claims priority from Application Serial No. u20110312, titled DEVICE FOR FORMATION OF LIGHT FIELD WITH CELLULAR INTENSITY DISTRIBUTION IN TRANSVERSAL SECTION filed on Apr. 19, 2011.
FIELD OF TECHNOLOGY
This disclosure relates generally to controlling microparticles and, more particularly, to controlling microparticles through a light field having controllable intensity and periodicity of maxima thereof.
BACKGROUND
Gradient light beams may be utilized for capturing and/or shifting of microparticles (e.g., influencing ensembles of micro-objects in microtechnology and/or nanotechnology applications with aims including but not limited to regulating movement and/or mixing thereof with regard to organic tissues as part of therapy and/or prophylaxis and influencing materials during localized laser processing). The mechanism of particle capturing may be based on aligning particle dipoles along the direction of a light field. When the light field contains a strong gradient, the particles may be attracted to a region of strongest electric field. The gradient may influence particles in a plane perpendicular to the axis of the light field.
When the longitudinal gradient force balances a dispersion force, the particles having higher refractive index than that of the environment may be captured and localized in intensity maxima of the light field. The particles having lower refractive index than that of the environment may be retracted in local intensity minima of the light field. Optical tweezers utilized for manipulating viruses and bacteria, inducing cellular synthesis in immunology and molecular genetics, capturing and shifting chromosomes, changing mobility of human spermatozoa and trans-membrane proteins etc. may be created based on the aforementioned principle. Gradient light fields may also be utilized for creating optical pumps, funnels and the like with an aim of filtrating particles and/or influencing living and non-living matter.
Devices utilized for forming gradient light fields may not allow for locally rounded intensity maxima to be formed. Although a Fresnel biprism allows formation of a static gradient light field in the form of parallel strips, the Fresnel biprism may not allow formation of a variable gradient light field in addition to not enabling formation of a light field having locally rounded intensity maxima.
An optical setup including a source of laser radiation, a telescope-collimator and a pyramid with four edges may enable formation of a gradient light field (e.g., a quadrabeam). However, the aforementioned gradient light field may be static, with a multitude of periodically distributed intensity maxima having same magnitudes in a transverse direction.
SUMMARY
Disclosed are a method, a device and/or a system of controlling microparticles through a light field having controllable intensity and periodicity of maxima thereof.
In one aspect, a method includes providing a capability to control divergence of a coherent light beam having an axially symmetrical distribution of intensity thereof through an optical divergence controller, and directing an output of the optical divergence controller related to the controlled divergence of the coherent light beam onto a glass prism. The glass prism includes a planar shape onto which a pyramidal structure is formed. The glass prism is positioned such that the output of the optical divergence controller is incident on a planar surface of the planar shape or the pyramidal structure.
The method also includes controlling a distance between maxima of an output light field of the glass prism and intensity thereof through controlling the divergence of the coherent light beam through the optical divergence controller and/or varying a distance between the optical divergence controller and the glass prism, and utilizing the output light field of the glass prism in controlling microparticles in a microtechnology or a nanotechnology application.
In another aspect, an optical device includes an optical divergence controller to provide a capability to control divergence of a coherent light beam having an axially symmetrical distribution of intensity thereof, and a glass prism including a planar shape onto which a pyramidal structure is formed. The glass prism is positioned such that an output of the optical divergence controller is incident on a planar surface of the planar shape or the pyramidal structure. Controlling the divergence of the coherent light beam through the optical divergence controller and/or varying a distance between the optical divergence controller and the glass prism enables controlling a distance between maxima of an output light field of the glass prism and intensity thereof. The output light field of the glass prism is configured to be utilized in controlling microparticles in a microtechnology or a nanotechnology application.
In yet another aspect, an optical system includes an optical divergence controller to provide a capability to control divergence of a coherent light beam having an axially symmetrical distribution of intensity thereof, and a glass prism including a planar shape onto which a pyramidal structure is formed. The glass prism is positioned such that an output of the optical divergence controller is incident on a planar surface of the planar shape or the pyramidal structure. The optical system also includes an ensemble of microparticles.
Controlling the divergence of the coherent light beam through the optical divergence controller and/or varying a distance between the optical divergence controller and the glass prism enables controlling a distance between maxima of an output light field of the glass prism and intensity thereof. The output light field of the glass prism is configured to be utilized in controlling the ensemble of microparticles.
The methods and systems disclosed herein may be implemented in any means for achieving various aspects, and may be executed in a form of a machine-readable medium embodying a set of instructions that, when executed by a machine, cause the machine to perform any of the operations disclosed herein. Other features will be apparent from the accompanying drawings and from the detailed description that follows.



BRIEF DESCRIPTION OF THE DRAWINGS
The embodiments of this invention are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:
FIG. 1 is a schematic view of an optical system, according to one or more embodiments.
FIG. 2 is a ray diagram of a convergent beam incident on a glass prism of the optical system of FIG. 1, according to one or more embodiments.
FIG. 3 is a ray diagram of a divergent beam incident on the glass prism of the optical system of FIG. 1, according to one or more embodiments.
FIG. 4 is a perspective view of the glass prism of the optical system of FIG. 1.
FIG. 5 is a plot of a longitudinal distribution of a convergent cellular field as a function of distance between the glass prism and an optical divergence controller of the optical system of FIG. 1.
FIG. 6 is a plot of a longitudinal distribution of a divergent cellular field as a function of distance between the glass prism and an optical divergence controller of the optical system of FIG. 1.
FIG. 7 is a process flow diagram detailing the operations involved in controlling microparticles through a light field having controllable intensity and periodicity of maxima thereof, according to one or more embodiments.



Other features of the present embodiments will be apparent from the accompanying drawings and from the detailed description that follows.
DETAILED DESCRIPTION
Example embodiments, as described below, may be used to provide a method, a device and/or a system of controlling microparticles through a light field having controllable intensity and periodicity of maxima thereof. Although the present embodiments have been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the various embodiments.
FIG. 1 shows an optical system 100, according to one or more embodiments. In one or more embodiments, optical system 100 may include a laser source 102 and a telescope collimator 104 configured to form a collimated coherent beam of light with axially symmetrical distribution of intensity. In one or more embodiments, the collimated coherent beam of light may be directed onto an optical divergence controller 106 that is configured to control divergence of the collimated coherent beam of light. In one example embodiment, optical divergence controller 106 may be a spherical lens with varying focal distance. Depending on the adjustment of optical divergence controller 106, convergent or divergent light beams may be generated therefrom.
In one or more embodiments, optical system 100 may include a glass prism 108 onto which the convergent or the divergent beam from optical divergence controller 106 is incident. In one example embodiment, glass prism 108 may include a rectangular cuboid onto which a square pyramid is formed. In one or more embodiments, a pyramidal surface of glass prism 108 may be a pure pyramid; alternately, the pyramidal surface may be a pyramid truncated on an edge thereof in a different manner (e.g., truncated on a square-shaped plane, a round-shaped plane, arbitrarily truncated). The shape(s) of glass prism 108 shown in FIG. 1, therefore, should not be considered limiting. In one example embodiment, glass prism 108 may be positioned such that the light beam is incident on a planar surface of the rectangular cuboid, with the square pyramid (an example shape) being along the direction of incidence; it should be noted that glass prism 108 may also be positioned such that the light beam is incident on a prism side thereof (and similarly for other variations of glass prism 108).
In one or more embodiments, when a convergent light beam is incident on glass prism 108, a convergent quadrabeam may be formed, with the convergent quadrabeam representing a cellular field in which the distance between maxima (or, cell period) decreases proportionally with distance. In one or more embodiments, when a divergent light beam is incident on glass prism 108, a divergent quadrabeam may be formed, with the divergent quadrabeam representing a cellular field in which the distance between maxima (or, cell period) increases with distance.
In one or more embodiments, through increasing divergence of the beam incident on glass prism 108 through optical divergence controller 106, the intensity of maxima of the cellular field and distances between maxima thereof (or, cell period) may be increased. Likewise, through decreasing divergence of the beam incident on glass prism 108 through optical divergence controller 106, the intensity of maxima of the cellular field and the distances between maxima thereof (or, cell period) may be decreased.
In one or more embodiments, with an increase in a width (or, dimension along the direction of incidence of the beam) of the square pyramid portion of glass prism 108, the distance between maxima of the cellular field (or, cell period) may increase. Likewise, with decrease in the width of the square pyramid portion of glass prism 108, the distance between maxima of the cellular field (or, cell period) may decrease. Thus, it may be possible to tune the distance between the maxima of the cellular field (or, cell period) through tuning divergence and/or through utilizing glass prisms (e.g., glass prism 108, or, another glass prism instead of glass prism 108) of varying widths.
FIG. 1 also shows a microscope 110 and a Charge Coupled Device (CCD) camera 112 to observe, register and/or investigate the cellular field. It is obvious that the aforementioned devices have been included merely for illustrative purposes, and that other devices within an experimental setup are within the scope of the exemplary embodiments. FIG. 2 shows a ray diagram of a convergent beam incident on glass prism 108, according to one or more embodiments. FIG. 3 shows a ray diagram of a divergent beam incident on glass prism 108, according to one or more embodiments. FIG. 4 shows a perspective view of glass prism 108, according to one or more embodiments.
FIG. 5 shows the longitudinal distribution of a convergent cellular field as a function of distance between glass prism 108 and optical divergence controller 106. As seen in FIG. 5, when the distance between glass prism 108 and optical divergence controller 106 is increased (from 10 mm to 50 mm to 90 mm), the distance between maxima in the intensity distribution across a transverse section of the convergent cellular field decreases. The beam incident on glass prism 108 may be more convergent as the distance between glass prism 108 and optical divergent controller 106 is increased, thereby contributing to the distance between maxima in the cellular field being reduced.
FIG. 6 shows the longitudinal distribution of a divergent cellular field as a function of distance between glass prism 108 and optical divergence controller 106. As seen in FIG. 6, when the distance between glass prism 108 and optical divergence controller 106 is increased (from 10 mm to 50 mm to 90 mm), the distance between maxima in the intensity distribution across a transverse section of the divergent cellular field increases. The beam incident on glass prism 108 may be more divergent as the distance between glass prism 108 and optical divergent controller 106 is increased, thereby contributing to the distance between maxima in the cellular field being increased.
Thus, in one or more embodiments, optical system 100 may allow for formation of a gradient light field with a cellular distribution of intensity in a transverse section thereof, the cellular distribution including a set of controllable periodically distributed intensity maxima. In one or more embodiments, the cell period of the cellular field may be controlled/regulated in an arbitrary plane perpendicular to an axis of symmetry thereof.
Exemplary embodiments may, therefore, allow for dosated (e.g., through laser) influence on ensembles of micro-objects (e.g., micro-particles) in microtechnology and nanotechnology applications as discussed above in the Background section. Referring back to FIG. 1, a sample 124 (e.g., micro-particles) may be placed (e.g., in a sample holder 122) such that particles of sample 124 are configured to interact with the gradient light field to be influenced thereby; in other words, sample 124 may be placed between glass prism 108 and microscope 110. In one example embodiment, sample holder 122 may be a cuvette; it should be noted that sample holder 122 may be made of various types of materials (e.g., glass). In one or more embodiments, sample holder 122 may/may not serve to shape the gradient light field.
FIG. 7 shows a process flow diagram detailing the operations involved in controlling microparticles through a light field having controllable intensity and periodicity of maxima thereof, according to one or more embodiments. In one or more embodiments, operation 702 may involve providing a capability to control divergence of a coherent light beam having an axially symmetrical distribution of intensity thereof through optical divergence controller 106. In one or more embodiments, operation 704 may involve directing an output of optical divergence controller 106 related to the controlled divergence of the coherent light beam onto glass prism 108. In one or more embodiments, glass prism 108 may include a planar shape onto which a pyramidal structure is formed.
In one or more embodiments, glass prism 108 may be positioned such that the output of optical divergence controller 106 is incident on a planar surface of the planar shape or the pyramidal structure. In one or more embodiments, operation 706 may involve controlling a distance between maxima of an output light field of glass prism 108 and intensity thereof through controlling the divergence of the coherent light beam through optical divergence controller 106 and/or varying a distance between optical divergence controller 106 and glass prism 108. In one or more embodiments, operation 708 may then involve utilizing the output light field of glass prism 108 in controlling microparticles in a microtechnology or a nanotechnology application.
Although the present embodiments have been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the various embodiments. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

## Claims

1. An optical device comprising:
a laser source;
a telescope collimator in an optical path immediately following the laser source to form a collimated coherent light beam having an axially symmetrical distribution of intensity thereof;
an optical divergence controller in an optical path immediately following the telescope collimator to provide a capability to control divergence of the collimated coherent light beam; and
a glass prism including a planar shape onto which a pyramidal structure is formed, the glass prism being positioned in an optical path immediately following the optical divergence controller such that an output of the optical divergence controller is incident on one of a planar surface of the planar shape and the pyramidal structure,
wherein at least one of: controlling the divergence of the collimated coherent light beam through the optical divergence controller and varying a distance between the optical divergence controller and the glass prism enables controlling a distance between maxima of an output light field of the glass prism and intensity thereof,
wherein the output light field of the glass prism is configured to be utilized in controlling microparticles in one of a microtechnology and a nanotechnology application, the microparticles being configured to be placed as part of a sample within a sample holder in an optical path immediately following the glass prism.

2. The optical device of claim 1, wherein the optical divergence controller is a spherical lens with varying focal distance.

3. The optical device of claim 1, further comprising at least one of a microscope and a CCD camera to at least one of observe, register and investigate the output light field of the glass prism.

4. The optical device of claim 1, wherein the output light field of the glass prism is configured to be utilized to allow for dosated laser influence on ensembles of the microparticles.

5. An optical system comprising:
a laser source;
a telescope collimator in an optical path immediately following the laser source to form a collimated coherent light beam having an axially symmetrical distribution of intensity thereof;
an optical divergence controller in an optical path immediately following the telescope collimator to provide a capability to control divergence of the collimated coherent light beam;
a glass prism including a planar shape onto which a pyramidal structure is formed, the glass prism being positioned in an optical path immediately following the optical divergence controller such that an output of the optical divergence controller is incident on one of a planar surface of the planar shape and the pyramidal structure; and
an ensemble of microparticles as part of a sample within a sample holder in an optical path immediately following the glass prism,
wherein at least one of: controlling the divergence of the collimated coherent light beam through the optical divergence controller and varying a distance between the optical divergence controller and the glass prism enables controlling a distance between maxima of an output light field of the glass prism and intensity thereof, and
wherein the output light field of the glass prism is configured to be utilized in controlling the ensemble of microparticles.

6. The optical system of claim 5, wherein the optical divergence controller is a spherical lens with varying focal distance.

7. The optical system of claim 5, further comprising at least one of a microscope and a CCD camera to at least one of observe, register and investigate the output light field of the glass prism.