Reduced speckle illumination system and method

Abstract

A laser source is provided, the laser source comprising at least one diode and a length of optical fiber disposed between the laser source and a target location such that the optical fiber transmits light pulses from the laser source as a light source to the target location, the location being illuminated by the light source to reduce speckle in a captured image of the target. Also provided is a method of providing source light for generating an image, the method including generating illumination using one or more laser diodes and passing the illumination through an optical fiber having a plurality of bends such that the source light is emitted from the optical fiber to illuminate the target with the source light, the source light reducing speckle in an image of the target.

Description

Technical Field

[0001] Related Applications This application claims the priority and benefit of U.S. Patent Application No. 63 / 125,259, "Reduced Speckle Illumination Systems and Methods" (filed December 14, 2020), and U.S. Patent Application No. 63 / 287,335, "Reduced Speckle Illumination Systems and Methods" (filed December 8, 2021). The foregoing applications are hereby incorporated herein by reference in their entirety for all purposes.

[0002] This disclosure relates to the field of laboratory illumination systems.

Background Art

[0003] Historically, speckle in conventional imaging has been addressed by averaging many different speckle patterns during camera exposure. However, such solutions are substantially active since they operate by generating a large number of speckle patterns and averaging the results over time, and also occur in the time domain. Some examples of these techniques include vibrating an optical fiber, passing light through a rotating disk of ground glass, and passing light through a rotating assembly of optical fibers.

[0004] The rotating disk can be, for example, 2 inches in diameter, rotated at 50,000 rpm, and have a displacement velocity at the disk edge of 10 micrometers / 100 ns. However, this configuration requires a significant amount of hardware and can increase the complexity and footprint of low-speckle devices. The vibrations used to provide multimode illumination can be in the range of tens of Hz to tens of kHz, and a 10 ns pulse may require a vibration frequency above 10 MHz since the displacement is proportional to 1 / frequency. However, vibration-based techniques can introduce undesirable hardware complexity.

[0005] While the aforementioned methods may be effective in speckle reduction in some cases, they also occur on a millisecond timescale, which makes the solution less suitable for the short exposure times required for flow cytometry. Therefore, there has been a long-standing need in the art for speckle reduction systems and methods suitable for use in flow cytometry applications, particularly systems and methods that produce speckle reduction on a timescale suitable for flow cytometry. [Overview of the project]

[0006] To satisfy the long-standing need described, the Disclosure first provides a light source for capturing an image, the light source comprising a laser source including at least one diode and an optical fiber arranged to transmit multimode optical pulses between the laser source and the target position in order to reduce speckle in a captured image of the target at the target position, wherein at least a portion of the optical fiber is present in one or more layers wound around a spindle, the spindle optionally including a perimeter in which the optical fiber is wound, and the layers include at least one tension winding of the optical fiber.

[0007] A method is also provided which includes operating a light source (for example, according to any one of embodiments 1 to 21) to illuminate a target.

[0008] A further method is provided, which includes arranging an optical fiber in optical communication with an illumination source such that the optical fiber is arranged to transmit light from the illumination source to a target positioned at the target location, wherein at least a portion of the optical fiber is present in one or more layers wound around a spindle, the spindle optionally including a perimeter in which the optical fiber is wound, and the layers include at least one tensioned winding of the optical fiber.

[0009] A method is also provided for providing light source for generating an image, the method comprising generating illumination using one or more laser diodes and passing the illumination through optical fibers present in one or more layers wound around a spindle, the spindle optionally including a perimeter with optical fibers wound between it, the layers including at least one tensioned winding of optical fibers, and passing the illumination is done so that multimode light source is emitted from the optical fibers to illuminate a target with illumination light, the illumination reduces speckle in the image of the target, and passing the illumination is done.

[0010] A cytometer is further disclosed, comprising: a flow cell configured to contain one or more particles internally, defining a target region; and an illumination train comprising at least (1) a laser source including at least one diode, and (2) an optical fiber communicating optically with the laser source, wherein at least a portion of the optical fiber is present in one or more layers wound around a spindle, the spindle optionally including a perimeter in which the optical fiber is wound, and the layers include at least one tension winding of the optical fiber.

[0011] Further disclosed is an imaging device comprising: a sample zone configured to include a sample therein; an illumination train comprising at least (1) a laser source including at least one diode; and (2) an optical fiber communicating optically with the laser source, wherein at least a portion of the optical fiber is in one or more layers wound around a spindle, the spindle optionally including a peripheral wall in which the optical fiber is wound, and the layers include at least one tension winding of the optical fiber; and an image capture device configured to capture an image of a sample placed within the sample zone region while it is illuminated by illumination from at least one diode transmitted through the optical fiber; the imaging device further optionally comprises a motion train configured to bring about relative motion between the sample in the sample zone and illumination from at least one diode transmitted through the optical fiber.

[0012] Furthermore, a light source is provided, the light source comprising a laser source including at least one diode, and an optical fiber arranged to transmit light between the laser source and the imaging surface to reduce the coherence of the light and thereby reduce speckle on the imaging surface, the optical fiber being bent around a support in part so as to generate mechanical tension within the optical fiber.

[0013] Methods are also provided that include operating a light source according to this disclosure (for example, a light source according to any one of embodiments 47 to 74). [Brief explanation of the drawing]

[0014] In drawings that are not necessarily drawn to a constant scale, the same numbers may represent similar components in different perspectives. Similar numbers with different letter suffixes may represent different instances of similar components. The drawings are illustrative, but not restrictive, in general to the various aspects discussed in this document. In the drawings, [Figure 1] This provides exemplary demonstrations of single-mode and multi-mode illumination transmitted through various optical fibers. [Figure 2] This provides an illustrative image of a 10-micrometer bead illuminated by a 10-ns illumination pulse transmitted through a 2-meter optical fiber. [Figure 3] This provides an illustrative depiction of speckle contrast as a function of the length of the fiber through which illumination is transmitted. [Figure 4] The present disclosure provides a diagram of an exemplary laser assembly showing multiple laser diodes communicating with an optical fiber. [Figure 5] The diagram shows a bead illuminated by a 100 ns illumination pulse transmitted through a 2 m optical fiber (left), and an equivalent bead illuminated by a 100 ns illumination pulse transmitted through a 50 m optical fiber (right). [Figure 6] This disclosure provides a diagram illustrating an exemplary system. [Figure 7] The diagrams show a tightly wound fiber spool (left panel) and a loosely wound fiber spool (right panel). [Figure 8] The diagram provides a fiber spool in which a fiber is wound over another fiber loop, resulting in a bulge in the fiber wound over the inner fiber loop. [Figure 9] The diagrams show layers of neatly wound fibers (left panel) and layers of randomly wound fibers (right panel), illustrating the intersections of the resulting fibers. [Figure 10] A diagram of an exemplary fiber winding configuration is provided. [Figure 11] This provides a cross-sectional view of the fiber layers in a spool of wound fibers. [Figure 12] The image of a loosely wound fiber spool (right panel) and the image collected by the loosely wound fiber spool (left panel) are provided. [Figure 13] The image of a tightly wound fiber spool (right panel) and the image collected by the tightly wound fiber spool (left panel) are provided. [Figure 14] This disclosure provides images generated by different fibers wound using the technique described herein, demonstrating the consistency and repeatability of the technique. [Figure 15] The present disclosure provides a diagram of the technology for manufacturing wound fibers, showing the winding of optical fibers by a custom spool supplied by a supply spool. [Modes for carrying out the invention]

[0015] This disclosure can be more readily understood by referring to the following detailed description of the desired embodiments and the examples contained herein.

[0016] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control. Although preferred methods and materials are described below, methods and materials similar or equivalent to those described herein can be used in practice or testing. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting.

[0017] The singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[0018] As used in this specification and the claims, the term "comprising" can include embodiments "consisting of" and "consisting essentially of". The terms "comprise", "include", "have", "has", "can", "contain", and variations thereof as used herein are intended as open-ended phrases, terms, or words that require the presence of the specified component / step and allow the presence of other components / steps. However, such descriptions should be construed as describing the composition or process as "consisting of" and "consisting essentially of" the recited component / step, which allows only the presence of the specified component / step with possible contaminants resulting therefrom and excludes other components / steps. essentially of)」を含み得る。本明細書で使用される用語「備える」、「含む」、「有する」、「有する」、「できる」、「包含する」、およびこれらの変形は、指定された成分 / ステップの存在を必要とし、他の成分 / ステップの存在を許容する、制約のない暫定的な語句、用語過ぎる。しかしながら、そのような説明は、列挙された成分 / ステップ「からなる」および「実質的にからなる」として、組成物またはプロセスを説明するものと解釈されるべきであり、これは、結果として生じる可能性のある混入物を伴う、指定された成分 / ステップのみの存在を可能にし、かつ他の成分 / ステップを排除するものである。

[0019] It should be noted that there seems to be an error in the original text where "terms, terms, or words" is repeated. The corrected translation is provided above.Where used herein, the terms “about” and “approximately” mean that the quantity or value in question may be approximately or nearly the same as any other specified value. Where used herein, it is generally understood to mean a nominal value with a variation of ±10%, unless otherwise indicated or inferred. The term is intended to convey that similar values ​​will facilitate equivalent results or effects described in the claims. That is, quantities, sizes, formulations, parameters, and other quantities and characteristics do not need to be exact, but are understood to be approximate and / or greater or less as necessary to reflect tolerances, conversion factors, rounding, measurement errors, and other factors known to those skilled in the art. In general, quantities, sizes, formulations, parameters, or other quantities or characteristics are “about” or “approximate,” whether so expressly stated. Where “about” is used before a quantitative value, it is understood that the parameter also includes the specific quantitative value itself, unless otherwise specified.

[0020] Furthermore, unless otherwise indicated, the numerical values ​​should be understood to include numerical values ​​that are the same when reduced to the same number of significant figures, and numerical values ​​that differ from the described value by a value less than the experimental error of the type of measurement technique of the ordinary measurement techniques described in this application for determining the value.

[0021] All ranges disclosed herein include, but are not related to, the endpoints described (2 grams and 10 grams, and all intermediate values). The ranges and endpoints of any values ​​disclosed herein are not limited to exact ranges or values, and they are sufficiently imprecise to include values ​​that approximate these ranges and / or values.

[0022] Where used herein, approximate terms may be applied to modify any quantitative expression that can change without altering the underlying function. Thus, values ​​modified by terms such as “about” and “substantially” may not be limited to a specific, definite value. In at least some examples, approximate terms may correspond to the precision of an instrument used to measure a value. The modifier “about” should also be considered to disclose a range defined by the absolute values ​​of two endpoints. For example, the expression “about 2 to about 4” also discloses the range “2 to 4”. The term “about” can refer to plus or minus 10% of the indicated number. For example, “about 10%” may indicate a range of 9% to 11%, and “about 1” may mean 0.9 to 1.1. Other meanings of “about,” such as rounding, may be evident from the context, for example, “about 1” may also mean 0.5 to 1.4. Furthermore, while the term “comprising” should be understood as having the open-ended meaning of “including,” it also encompasses the closed meaning of the term “consisting.” For example, a composition containing components A and B may be a composition containing A, B, and other components, but it may also be a composition consisting only of A and B. All documents cited herein are incorporated herein by reference in their entirety for all purposes.

[0023] As the development of CMOS sensors offering higher speeds and quantum efficiencies progresses, cameras are becoming more suitable for flow cytometry applications. Coupled with advances in high-power laser diodes and the resulting decrease in the cost per watt of optical power, combining high-speed cameras with laser sources is a compelling technique for use in flow cytometry imaging. However, the effectiveness of such a technique can be somewhat diminished by the presence of undesirable laser speckles in the images acquired by the camera.

[0024] To reduce this undesirable speckle, the disclosure provides, among other things, the use of optical fibers to deliver multimode illumination to a target, which reduces speckle in imaging of that target.

[0025] Multimode illumination can be performed in many ways, for example, using multimode fibers. Multimode fibers can contain thousands or tens of thousands of propagation modes. Each mode has a different spatial path during propagation, as shown in Figure 1 attached to this specification. This can result in temporal diffusion of light at the fiber output. A rough explanation of speckle reduction is that different modes can be considered as many different sources, thereby generating different speckle patterns.

[0026] In addition to geometric mode diffusion, additional perturbations to the fiber and / or excitation can be introduced, which can increase coupling to higher-order modes. For example, increasing the angle of the cone of the excitation light entering the fiber can increase mode coupling. This allows the light to couple to higher-order modes that propagate at a larger angle within the fiber. For this reason, fibers with relatively high numerical apertures and higher-order mode numbers can be used. As a non-limiting example, fibers with numerical aperture values ​​of approximately 0.2 to approximately 0.55 can be used. Bending, winding, or otherwise bending the optical fiber can have the effect of bending the light from lower modes to higher modes over long distances in order to further mix modes and access higher-order modes.

[0027] The source bandwidth allows for further mixing of modes. Different wavelengths have different mode patterns, thereby creating different mode structures across the wavelength array. For this reason, a multi-mode light source (e.g., a laser diode), such as a first diode emitting light at a first wavelength and a second diode emitting light at a second wavelength, can be used. A multimode diode, such as a diode that emits laser light at multiple wavelengths, can also be used.

[0028] Existing methods use relatively short optical fibers, and over that short length, passive mode mixing is small, making them inefficient in reducing speckle in images. As described elsewhere in this specification, some techniques use vibration or motion to deform the optical fiber cable, thereby creating and accessing more geometric modes for use in averaging out a large number of speckle patterns.

[0029] Most conventional microscopy techniques use exposure times ranging from tens to hundreds of milliseconds, allowing most applications to vibrate the fiber on a millisecond timescale. However, for the high-speed imaging required in flow cytometry, mode mixing must be achieved within a time window of around 100 nanoseconds, several orders of magnitude shorter than the time windows suitable for conventional microscopy. Consequently, this relatively short time window prevents the use of most current active speckle reduction techniques in flow cytometry.

[0030] In this disclosure, the properties of a multimode fiber are used in ultrafast speckle reduction techniques. This can be achieved by using the slow mode mixing / pulsed diffusion properties of the multimode fiber coupled with the enumerated additional perturbations to increase mode mixing. In this embodiment, different fiber lengths and laser wavelength bandwidths than those seen in typical imaging applications can be used.

[0031] High-speed speckle reduction can be achieved by using each of the techniques listed above to increase passive mode mixing. Independently, mixing is not suitable, but by moving parameters from current standards and combining techniques, good speckle reduction can be achieved on very short time scales.

[0032] In one embodiment, a relatively long (e.g., 50 m in length) multimode high numerical aperture fiber is inserted between the light source and the imaging target. The fiber can be wound around a spindle so that it has continuous bends that allow access to further modes. Furthermore, the light source bandwidth can be increased by coupling light from multiple laser diodes of slightly different wavelengths into the fiber. These effects are additive.

[0033] figure The attached figures are illustrative and do not necessarily limit the scope of this disclosure or the attached claims.

[0034] Figure 1 provides illustrative diagrams of single-mode and multi-mode illumination transmitted through various optical fibers—single-mode / step-index, multi-mode / graded-index, and multi-mode / step-index.

[0035] Figure 2 provides an illustrative image of a 10-micrometer bead illuminated by a 10-ns illumination pulse transmitted through a 2-meter optical fiber.

[0036] Figure 3 provides an illustrative depiction of speckle contrast as a function of the length of the fiber through which illumination is transmitted. As shown, the NA of the fiber (0.2 corresponds to line 300, 0.3 to line 302, and 0.4 to line 304) can affect the speckle contrast, which is then expanded as a function of fiber length. For example, at a fiber length of 50m, a fiber with an NA of 0.4 exhibits relatively lower speckle contrast compared to a fiber with an NA of 0.2.

[0037] Figure 4 provides a diagram of an exemplary laser assembly according to the present disclosure. As shown, the assembly may include multiple laser diodes communicating with an optical fiber.

[0038] Figure 5 provides a diagram of a 10-micron bead 504 (left) moving at 4 m / s within background 506 and illuminated by a 100 ns pulse transmitted through a 2 m multimode optical fiber, and an equivalent bead 500 (right) illuminated by a 100 ns pulse transmitted through a 50 m multimode optical fiber wound on a spindle (moving within background 502), both fibers having an NA of 0.5. Multiple laser diodes with a high NA of 0.5 were used to illuminate a 50 m length fiber using multiple laser diodes with wavelengths around 405 nm. The target was strobed using optical pulses synchronized between multiple diodes for approximately 100 nanoseconds, and the exposure time was approximately 6 microseconds. Thus, the use of the disclosed method resulted in a significant difference (right panel) compared to a comparative method (left panel).

[0039] Figure 6 provides a diagram of an exemplary system according to the present disclosure. As shown, the system 600 may include a controller 602 that can communicate with one or more laser diodes 604, the diodes may be single-mode or multimode diodes. The laser diodes 604 may communicate with an optical fiber 606, which may be a multimode fiber. The fiber 606 may also be wound around a spindle (or multiple spindles) and may be curved or bent in other ways. The illumination delivered from the fiber 606 may be delivered to a location 610, for example, a flow cell, a microscope stage, or another location where a sample is illuminated. The image capture train 608 then captures an image of the illuminated sample at the sample location 610, the image showing reduced speckle. The controller 602 may communicate with the image capture train 608, but this is not required, and the image capture train may communicate with an alternative controller.

[0040] Figure 7 provides diagrams of a tightly wound fiber spool (left panel) and a loosely wound fiber spool (right panel). As shown, a loosely wound fiber does not have a consistent radius around its circumference. While not bound by any particular theory or embodiment, tightly winding a fiber generates a constant bending radius so that only a certain order of propagation modes is retained within the fiber core. In contrast, if the fiber is a loosely wound spool or the fiber is slack, the bending radius of the fiber is not well controlled, and the light may be coupled to different orders of modes other than the desired mode.

[0041] Figure 8 provides a diagram of a fiber spool in which a fiber is wound "crossing" over another fiber loop, resulting in a bulge in the fiber wound over the inner fiber loop. Although not bound by any particular theory or embodiment, having such crossings can result in non-uniform fiber radii. Winding a fiber over another loop of fiber can introduce different bending radii, which can result in the generation of different order modes. Therefore, when a fiber is neatly wound around a spindle or spool, such windings avoid having small bends of different radii, which can reduce the number of crossings, potentially propagate higher-order modes, and / or reduce fiber transmission.

[0042] Figure 9 provides diagrams of layers of neatly wound fibers (left panel) and layers of randomly wound fibers (right panel), showing the resulting fiber crossovers. As shown in Figure 8, the presence of such crossovers (several are shown in Figure 9) can lead to non-uniform or inconsistent fiber radii.

[0043] Figure 10 provides a diagram of an exemplary fiber winding configuration. Although not bound by any particular theory or embodiment, the fiber can be wound around a spindle in a roll-to-roll manner, with the fiber source and / or fiber winding spindle rotating circumferentially and the source and / or winding spindle moving axially to achieve fiber wrapping that is free or substantially free of crossings, as shown in Figure 8. The fiber windings can be arranged in an alternating left-to-right winding pattern, for example, as shown in Figure 11.

[0044] Figure 11 provides a cross-sectional view of the fiber layers in a spool of wound fiber. As shown, a given layer of fiber may have the same number of turns as the layers below or above it, but this is not a requirement.

[0045] In Figure 11, the numbers in the circles indicate the nth loop of the winding process. The two vertical lines indicate the walls on the spool. The winding process begins with the first loop in the bottom layer, followed by the second loop, the third loop, and so on. When the fiber reaches the other wall, it moves to the next layer and continues winding around the second layer. This process continues until the entire length of the fiber (e.g., 50 meters) is wound onto the spool. Throughout the winding process, the fiber may be wound tightly to ensure a consistent bending radius.

[0046] Figure 12 provides images of a loosely wound fiber spool (right panel) and images collected by that loosely wound fiber spool (left panel). As shown, areas of contrast in the images are difficult to identify. While not bound by any particular theory, the loosely wound fiber resulted in higher-order modes near the beam center, insufficient contrast, and considerable speckle.

[0047] Figure 13 provides an image of a tightly wound fiber spool (right panel) and an image collected by that tightly wound fiber spool (left panel). As shown (and by comparison with Figure 13), the image exhibits improved contrast compared to Figure 12, which was produced using a loosely wound fiber spool.

[0048] Figure 14 provides images generated by different fibers wound by the technique described herein, demonstrating the consistency and repeatability of the technique. While not bound by any particular theory or embodiment, tighter windings result in better "mode filtering," removing higher-order modes of illumination transmitted through the fiber. Again, while not bound by any particular theory or embodiment, inconsistent bending radii may, in some cases, allow higher-order modes to propagate and increase speckle.

[0049] Figure 15 provides a diagram of the technology for manufacturing wound fibers according to the present disclosure, showing the winding of optical fibers by a custom spool supplied by a supply spool.

[0050] manner The following embodiments are illustrative and do not limit the scope of this application or the attached claims.

[0051] Embodiment 1. A light source for capturing an image, comprising: a laser source including at least one diode; and an optical fiber arranged to transmit a plurality of mode light pulses between the laser source and a target position to reduce speckle in a captured image of a target at a target position, wherein at least a portion of the optical fiber is present in one or more layers wound around a spindle, the spindle optionally including a peripheral wall in which the optical fiber is wound, and the layers include at least one tension winding of the optical fiber. "Tension" means that there is no slack in the optical fiber, for example, there is virtually no space beneath the optical fiber. An example is shown in Figure 11, where the winding of the optical fiber (e.g., winding N+3 shown in Figure 11) is taut. The laser source may include one, two, three, or more diodes, for example, multiple diodes. The diodes may be single-mode diodes or multi-mode diodes. One or more laser sources can provide illumination at one or more wavelengths, for example, 405, 450, 488, 532, 561, and 640 nm. Diodes can also provide illumination in a wavelength range, for example, 400–410 nm. Embodiment 2. The light source according to Embodiment 1, wherein the layers of optical fibers include at least two tensioned windings of optical fibers that are substantially parallel to each other. As described elsewhere in this specification, optical fibers can be arranged around the spindle, but this is not a requirement, as optical fibers can be arranged in trays or other features that accommodate the bending or undulation within the optical fibers. Although not bound by any particular theory or embodiment, optical fibers can be arranged within or even on the housing of the instrument. In this way, the unit can be configured to accommodate relatively long optical fibers while maintaining a relatively small footprint. The light source may include a spindle around which optical fibers are arranged to cause a bend in the optical fibers. The spindle may have a circular cross-section, or it may have an oval or polygonal cross-section. The spindle may have a constant diameter along its height, or its diameter may vary, for example, it may be conical or frustoconical. The spindle may taper upwards, or it may be wider at the top and narrower at the bottom. Such a spindle may have a constant cross-sectional profile, for example. The spindle may have a variable cross-section, for example, by being expandable. In such embodiments, adjustment of the spindle's cross-section (for example, by increasing the cross-sectional dimensions of the spindle, by changing the cross-sectional profile of the spindle, or by decreasing the cross-sectional dimensions of the spindle) can adjust the illumination delivered to the target. Embodiment 3. The light source according to Embodiment 1 or 2, wherein the winding of the optical fiber in the outer layer is substantially parallel to the winding of the optical fiber in the inner layer directly beneath the outer layer. The light source according to this disclosure may also include a processing or control train. Such a processing or control train may be configured to adjust the settings of the illumination supplied to a target to achieve a specific speckle contrast (for example, by changing the characteristics of the illumination supplied by one or more laser diodes, or by changing the characteristics of the optical fiber). Speckle contrast is defined as the standard deviation of spatial intensity divided by the average intensity measured in a given area, and is expressed as a dimensionless number. While not bound by any particular theory, typically, lower speckle contrast values ​​are desirable. For example, if a first set of light source settings produces the desired speckle contrast for a first sample but not for a second sample, the processing or control train may be configured to adjust the lighting settings so that the desired speckle contrast is achieved for the second sample. Lighting settings can be adjusted automatically, but they can also be adjusted manually. Embodiment 4. A light source according to any one of Embodiments 1 to 3, wherein the winding of the optical fiber in the outer layer does not intersect with the winding of the optical fiber in the inner layer directly beneath the outer layer. Such a configuration is shown in Figure 10. Embodiment 5. Including an inner layer of the optical fiber containing multiple tension windings of the optical fiber, and an outer layer of the optical fiber containing multiple tension windings of the optical fiber, (i) Multiple tension windings of the optical fiber in the outer layer are parallel to each other, (ii) Multiple tension windings of the optical fiber within the inner layer are parallel to each other, (iii) A light source according to any one of embodiments 1 to 4, wherein multiple tension windings of optical fibers in the outer layer are parallel to multiple windings of optical fibers in the inner layer. Such a configuration is shown in Figure 11. Embodiment 6. A light source according to any one of Embodiments 1 to 5, wherein the spindle has a fixed cross-sectional dimension. Embodiment 7. A light source according to any one of Embodiments 1 to 5, wherein the spindle has variable cross-sectional dimensions. Embodiment 8. A light source according to any one of Embodiments 1 to 7, wherein the spindle has a cross-sectional dimension of approximately 1 cm to approximately 10 cm. Embodiment 9. A light source according to any one of Embodiments 1 to 8, wherein the optical pulses from the laser source are synchronized. For example, if the laser source includes three diodes, the optical pulses from the three diodes can be synchronized with each other. However, synchronization is not a requirement. Embodiment 10. A light source according to any one of Embodiments 1 to 9, wherein light from a laser source is pulsed at approximately 100 nanoseconds to strobe a target. The light pulses may be approximately 5 milliseconds to approximately 1 nanosecond, for example, approximately 1 millisecond to approximately 1 nanosecond, or approximately 0.5 milliseconds to approximately 10 nanoseconds, or even approximately 100 nanoseconds to approximately 10 nanoseconds. Embodiment 11. A light source according to any one of Embodiments 1 to 10, further comprising an image capture device configured to capture a target capture image, wherein the captured image optionally has an exposure of about 6 microseconds. The image capture train may include a camera (CCD, sCMOS, CMOS), a PMT array, an avalanche photodiode, a photodiode array, or other modules. The image capture train may include a processor configured to process the images collected by the image capture train. Embodiment 12. A light source according to any one of Embodiments 1 to 11, wherein the optical fiber is a multimode optical fiber. Embodiment 13. A light source according to any one of Embodiments 1 to 12, wherein the optical fiber is a high numerical aperture optical fiber. As an example, a fiber having a numerical aperture greater than approximately 0.22 is considered a high numerical aperture optical fiber. Embodiment 14. A light source according to any one of Embodiments 1 to 13, wherein the numerical aperture of the optical fiber is approximately 0.5. The numerical aperture may be, for example, approximately 0.1 to approximately 0.5, for example, approximately 0.1 to approximately 0.5, approximately 0.15 to approximately 0.45, approximately 0.2 to approximately 0.4, approximately 0.25 to approximately 0.35, or even approximately 0.3. Embodiment 15. A light source according to any one of Embodiments 1 to 14, wherein the length of the optical fiber is about 2 meters to about 75 meters. The fiber may be, for example, about 2 to about 75 meters, about 5 to about 70 meters, about 10 to about 65 meters, about 15 to about 60 meters, about 20 to about 55 meters, about 25 to about 50 meters, about 30 to about 45 meters, or even about 35 to about 40 meters. Embodiment 16. The light source according to Embodiment 15, wherein the length of the optical fiber is approximately 50 meters. Embodiment 17. A light source according to any one of Embodiments 1 to 16, wherein the laser source comprises a plurality of laser diodes, each of which is spatially separated from the other laser diodes among the plurality of laser diodes. Embodiment 18. The light source according to any one of Embodiments 1 to 17, wherein the position of the target is spatially separated from the plurality of laser diodes. Embodiment 19. The light source according to any one of Embodiments 1 to 18, wherein the laser source includes a first laser diode that generates light source light at a predetermined wavelength. Embodiment 20. The light source according to any one of Embodiments 1 to 19, wherein the laser source includes at least one multimode laser diode. Embodiment 21. A light source according to any one of Embodiments 1 to 20, wherein the laser source includes a plurality of laser diodes, and at least one of the plurality of laser diodes generates light of a different wavelength from another laser diode among the plurality of laser diodes. Embodiment 22. A method comprising operating a light source according to any one of Embodiments 1 to 21 to illuminate a target. The target may be located in a flow cell, for example, in a flow cytometer. The target may be moving (e.g., a cell in a flow cytometer) or stationary. For example, the target may be positioned in a microscope system, for example, on a microscope stage. Embodiment 23. The method according to Embodiment 22, further comprising collecting images of a target. Embodiment 24. A method comprising arranging an optical fiber in optical communication with an illumination source such that the optical fiber is arranged to transmit light from the illumination source to a target positioned at the target location, wherein at least a portion of the optical fiber is present in one or more layers wound around a spindle, the spindle optionally including a perimeter in which the optical fiber is wound, and the layers include at least one tensioned winding of the optical fiber. Embodiment 25. The method of Embodiment 24, wherein the layers of optical fibers include at least two tensioned windings of optical fibers that are substantially parallel to each other. Embodiment 26. The method according to any one of Embodiments 24 to 25, wherein the winding of the optical fiber in the outer layer is substantially parallel to the winding of the optical fiber in the inner layer directly beneath the outer layer. Embodiment 27. The method according to any one of Embodiments 24 to 26, wherein the winding of the optical fiber in the outer layer does not intersect with the winding of the optical fiber in the inner layer directly beneath the outer layer. Embodiment 28. The optical fiber exists as an inner layer of the optical fiber containing multiple tension windings and an outer layer of the optical fiber containing multiple tension windings. (i) Multiple tension windings of the optical fiber in the outer layer are parallel to each other, (ii) Multiple tension windings of the optical fiber within the inner layer are parallel to each other, (iii) The method according to any one of embodiments 24 to 27, wherein multiple tension windings of the optical fiber in the outer layer are parallel to multiple windings of the optical fiber in the inner layer. Embodiment 29. A method for providing light source for generating an image, comprising: generating illumination using one or more laser diodes; and passing the illumination through optical fibers present in one or more layers wound around a spindle, wherein the spindle optionally includes a perimeter in which optical fibers are wound, and the layers include at least one tensioned winding of optical fibers; passing the illumination through is performed so that multimode light source is emitted from the optical fibers to illuminate a target with illumination light; and the illumination reduces speckle in the image of the target. Embodiment 30. The method according to Embodiment 29, wherein the illumination is produced by at least two laser diodes that produce light of different wavelengths from each other, such that at least two laser diodes produce illumination having multiple modes. Embodiment 31. The method according to any one of Embodiments 29 to 30, wherein generating light from a light source includes generating a synchronization light pulse from at least one laser diode. Embodiment 32. The method according to any one of Embodiments 29 to 31, wherein generating illumination comprises pulsing at least one of one or more laser diodes with a period of about 100 nanoseconds to strobe a target. Embodiment 33. The method according to any one of Embodiments 29 to 32, further comprising capturing an image of a target with an image capture device, wherein the image capture device optionally has an exposure time of about 6 microseconds. Embodiment 34. The method according to any one of Embodiments 29 to 32, wherein the optical fiber is a multimode optical fiber. Embodiment 35. The method according to any one of Embodiments 29 to 34, wherein the optical fiber is a high numerical aperture optical fiber. Embodiment 36. The method according to Embodiment 35, wherein the numerical aperture of the optical fiber is approximately 0.5. Embodiment 37. The method according to any one of Embodiments 29 to 36, wherein the length of the optical fiber is approximately 2 meters to approximately 50 meters. Embodiment 38. The method according to Embodiment 37, wherein the length of the optical fiber is approximately 50 meters. Embodiment 39. The method according to any one of Embodiments 29 to 38, wherein illumination is generated by a plurality of laser diodes, and each of the plurality of laser diodes is spatially separated from the others. Embodiment 40. The method according to any one of Embodiments 29 to 39, wherein the target is located within a flow cell. Embodiment 41. The method according to any one of embodiments 29 to 40, further comprising bringing about relative motion between the light source and the target. Embodiment 42. The method according to any one of Embodiments 29 to 41, wherein the target is stationary while the light is being applied. Embodiment 43. The method according to any one of Embodiments 29 to 42, wherein the target is moving while the light is being applied. Embodiment 44. A cytometer comprising: a flow cell configured to contain one or more particles internally and defining a target region; and an illumination train comprising at least (1) a laser source including at least one diode; and (2) an optical fiber communicating optically with the laser source, wherein at least a portion of the optical fiber is present in one or more layers wound around a spindle, the spindle optionally including a peripheral wall in which the optical fiber is wound, and the layers include at least one tension winding of the optical fiber. The cytometer may include one or more of the following: hydrodynamic or sheath fluid focusing and acoustic radiation pressure focusing. Hydrodynamic focusing is known to those skilled in the art, and an exemplary consideration of acoustic radiation pressure focusing can be found, for example, in U.S. Patent Application Publication No. 2020 / 0072795 by Kaduchak et al. Embodiment 45. The cytometer according to Embodiment 44, further comprising an image capture device configured to capture an image of a target placed within a target region while being illuminated by illumination from at least one diode transmitted through an optical fiber. Embodiment 46. Imaging apparatus comprising: a sample zone configured to include a sample therein; an illumination train comprising at least (1) a laser source including at least one diode; and (2) an optical fiber communicating optically with the laser source, wherein at least a portion of the optical fiber is in one or more layers wound around a spindle, the spindle optionally including a peripheral wall in which the optical fiber is wound, and the layers include at least one tension winding of the optical fiber; and an image capture device configured to capture an image of a sample placed within the sample zone region while it is illuminated by illumination from at least one diode transmitted through the optical fiber, and further optionally comprising a motion train configured to bring about relative motion between the sample in the sample zone and the illumination from at least one diode transmitted through the optical fiber. Embodiment 47. A light source comprising a laser source including at least one diode, and an optical fiber arranged to transmit light between the laser source and an imaging surface to reduce the coherence of the light and thereby reduce speckle on the imaging surface, wherein at least a portion of the optical fiber is bent around a support to generate mechanical tension within the optical fiber. Embodiment 48. The light source according to Embodiment 47, wherein the support is characterized as a spindle. Embodiment 49. The light source according to Embodiment 47, wherein the support is characterized as a column. Embodiment 50. A light source according to any one of Embodiments 47 to 49, wherein the support defines a certain cross-sectional dimension. Embodiment 51. A light source according to any one of Embodiments 47 to 50, wherein the optical fiber includes at least one winding surrounding a support. Embodiment 52. The light source according to Embodiment 51, wherein the optical fiber includes a plurality of windings surrounding a support. Embodiment 53. The light source according to Embodiment 52, wherein the optical fiber includes multiple layers surrounding a support, and each layer includes multiple windings. Embodiment 54. The light source according to any one of Embodiments 47 to 53, wherein the light source is configured to produce speckle of less than approximately 2% on the imaging surface. Embodiment 55. The light source according to Embodiment 54, wherein the light source is configured to produce speckle of less than approximately 1% on the imaging surface. Embodiment 56. The light source according to Embodiment 54, wherein the light source is configured to produce approximately 1% speckle on the imaging surface. Embodiment 57. A light source according to any one of Embodiments 47 to 56, wherein the optical fiber has a long-term bending radius, and the optical fiber can be bent at a radius smaller than the long-term bending radius. Embodiment 58. A light source according to any one of Embodiments 47 to 57, wherein the transmittance of light passing through the optical fiber is approximately 60% to approximately 90%. Embodiment 59. The light source according to Embodiment 58, wherein the transmittance is approximately 75% to approximately 90%. Embodiment 60. A light source according to any one of Embodiments 47 to 59, wherein the imaging surface is located within a flow cell. Embodiment 61. The light source according to Embodiment 60, wherein the flow cell is included in a flow cytometer. Embodiment 62. A light source according to any one of Embodiments 47 to 61, wherein mechanical tension maintains the optical fiber in a state of tension. Embodiment 63. A light source according to any one of Embodiments 47 to 62, wherein the laser source provides light as optical pulses, and the optical pulses are optionally synchronized. Embodiment 64. The light source according to Embodiment 63, wherein light from a laser source is pulsed at approximately 100 nanoseconds to strobe a target. Embodiment 65. A light source according to any one of Embodiments 47 to 64, further comprising an image capture device configured to capture a target capture image, wherein the captured image optionally has an exposure of about 6 microseconds. Embodiment 66. A light source according to any one of Embodiments 47 to 65, wherein the optical fiber is a multimode optical fiber. Embodiment 67. The light source according to any one of Embodiments 47 to 66, wherein the optical fiber is a high numerical aperture optical fiber. Embodiment 68. A light source according to any one of Embodiments 47 to 67, wherein the numerical aperture of the optical fiber is approximately 0.5. Embodiment 69. A light source according to any one of Embodiments 47 to 68, wherein the length of the optical fiber is approximately 2 meters to approximately 75 meters. Embodiment 70. The light source according to Embodiment 69, wherein the length of the optical fiber is approximately 50 meters. Embodiment 71. A light source according to any one of Embodiments 47 to 70, wherein the laser source comprises a plurality of laser diodes, each of which is spatially separated from the other laser diodes among the plurality of laser diodes. Embodiment 72. The light source according to any one of Embodiments 47 to 71, wherein the laser source includes a first laser diode that generates light source light at a predetermined wavelength. Embodiment 73. The light source according to any one of Embodiments 47 to 72, wherein the laser source includes at least one multimode laser diode. Embodiment 74. A light source according to any one of embodiments 47 to 73, wherein the laser source includes a plurality of laser diodes, and at least one of the plurality of laser diodes generates light of a different wavelength from another of the plurality of laser diodes. Embodiment 75. A method comprising operating a light source described in any one of Embodiments 47 to 74. Embodiment 76. The method according to Embodiment 75, comprising illuminating one or more particles or cells on the imaging surface. Embodiment 77. The method according to Embodiment 76, further comprising collecting an image of a target located on an imaging surface and illuminated by a light source.

Claims

1. A light source, A laser source including at least one diode, An optical fiber arranged to transmit optical pulses having multiple modes between the laser source and the target location in order to reduce speckle in the captured image of the target at the target location, At least a portion of the optical fiber is present in multiple layers wound around the spindle, The spindle includes a peripheral wall around which an optical fiber is wound, Each of the aforementioned layers includes an N-turn loop of the tensioned and wound optical fiber, Each of the aforementioned layers is stacked on the spindle from the inside out. A light source comprising an optical fiber wound around a spindle, wherein the optical fiber is wound around the spindle such that the Nth loop of the second layer is positioned between the first loop and the second loop of the first layer among the plurality of layers, and so on.

2. The light source according to claim 1, wherein the winding of the optical fiber in the outer layer is substantially parallel to the winding of the optical fiber in the inner layer directly beneath the outer layer.

3. The light source according to claim 1, wherein the winding of the optical fiber in the outer layer does not intersect with the winding of the optical fiber in the inner layer directly beneath the outer layer.

4. The optical fiber includes an inner layer containing multiple tension windings of the optical fiber, and an outer layer containing multiple tension windings of the optical fiber, (i) The plurality of tension windings of the optical fiber in the outer layer are parallel to each other, (ii) The plurality of tension windings of the optical fiber in the inner layer are parallel to each other, (iii) The light source according to claim 1, wherein the plurality of tension windings of the optical fiber in the outer layer are parallel to the plurality of windings of the optical fiber in the inner layer.

5. The light source according to claim 1, wherein the spindle has a constant cross-sectional dimension.

6. The light source according to claim 1, wherein the spindle has different cross-sectional dimensions depending on its axial position.

7. The light source according to claim 1, wherein the spindle has a cross-sectional dimension of about 1 cm to about 10 cm.

8. The light source according to claim 1, wherein the laser source includes a plurality of laser diodes, and the light pulses from each laser diode are synchronized with each other.

9. The light source according to claim 1, wherein the light from the laser source is pulsed at approximately 100 nanoseconds to strobe the target.

10. The light source according to claim 1, further comprising an image capture device configured to capture the captured image of the target.

11. The light source according to claim 1, wherein the optical fiber is a multimode optical fiber.

12. The light source according to claim 1, wherein the optical fiber is a high numerical aperture optical fiber.

13. The light source according to claim 1, wherein the numerical aperture of the optical fiber is approximately 0.

5.

14. The light source according to claim 1, wherein the length of the optical fiber is approximately 2 meters to approximately 75 meters.

15. The light source according to claim 14, wherein the length of the optical fiber is approximately 50 meters.

16. The light source according to claim 1, wherein the laser source includes a plurality of laser diodes, each of the plurality of laser diodes is spatially separated from the other laser diodes among the plurality of laser diodes.

17. The light source according to claim 1, wherein the laser source includes a plurality of laser diodes, and the target position of the target is spatially separated from the plurality of laser diodes.

18. The light source according to claim 1, wherein the laser source includes a first laser diode that generates light from the light source at a predetermined wavelength.

19. The light source according to claim 1, wherein the laser source includes at least one multimode laser diode.

20. The light source according to claim 1, wherein the laser source includes a plurality of laser diodes, and at least one of the plurality of laser diodes generates light of a different wavelength from another of the plurality of laser diodes.

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