Tuning for flow cytometer

Abstract

Methods of tuning an illumination assembly of a flow cytometer are described. One method of tuning the illumination assembly of the flow cytometer includes receiving a first alignment error for a first laser diode of the illumination assembly, installing a tuning device in the flow cytometer, and adjusting a first switch associated with the first laser diode. Another method of tuning the illumination assembly of the flow cytometer includes inserting an oscillating wave signal into a drive circuit of the illumination assembly. The oscillating wave signal provides a frequency modulation of the drive circuit.

Description

TUNING FOR FLOW CYTOMETERCROSS REFERENCE TO RELATED APPLICATION

[0001] This application is being filed on January 31, 2025, as a PCT International application and claims the benefit of and priority' to U.S. Provisional Patent Application No. 63 / 558,176, filed on February 27, 2024, the disclosure of which is hereby incorporated by reference in its entirety.BACKGROUND

[0002] In flow cytometry', particles are arranged in a sample stream, and ty pically pass one-by-one through one or more excitation light beams with which the particles interact. Light scattered or fluoresced by' the particles upon interaction with the one or more excitation beams is collected and analyzed to characterize and differentiate the particles. In a sorting flow cytometer, particles may be extracted out of the sample stream after having been characterized by their interaction with the one or more excitation beams, and thereby sorted into different groups.SUMMARY

[0003] In general terms, the present disclosure relates to tuning an illumination assembly for a flow cytometer. In one possible configuration, a tuning device is used to adjust a parameter associated with one or more laser diodes of the illumination assembly. In another possible configuration, the tuning device inserts an oscillating wave signal into a drive circuit of the illumination assembly to provide a frequency modulation of the laser diodes. Various aspects are described in this disclosure, which include, but are not limited to, the following aspects.

[0004] One aspect relates to a method of tuning an illumination assembly’ of a flow cytometer, the method comprising: receiving a first alignment error for a first laser diode of the illumination assembly; installing a tuning device in the flow cytometer; and adjusting a first switch associated with the first laser diode.

[0005] Another aspect relates to a device for tuning an illumination assembly of a flow cytometer, the device comprising: a connector for connecting to the illumination assembly; and one or more switches for adjusting one or more laser diodes of the illumination assembly, the one or more switches being adjustable between different settings for tuning each laser diode of the one or more laser diodes.

[0006] A variety of additional aspects will be set forth in the description that follows. The aspects can relate to individual features and to combination of features. Itis to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosed herein are based.DESCRIPTION OF THE FIGURES

[0007] The following drawing figures, which form a part of this application, are illustrative of the described technology and are not meant to limit the scope of the disclosure in any manner.

[0008] FIG. 1 illustrates an example of a system for performing flow cytometry, the system including a flow cytometer and a workstation.

[0009] FIG. 2 illustrates an example of an illumination assembly in the flow cytometer of FIG. 1.

[0010] FIG. 3 shows an example of a tuning device for tuning the illumination assembly of FIG. 2.

[0011] FIG. 4 schematically illustrates an example of a method of tuning the illumination assembly of FIG. 2 by using the tuning device of FIG. 3.

[0012] FIG. 5 shows an example of a thermoelectric cooler (TEC) control board inside the flow cytometer of FIG. 1.

[0013] FIG. 6 shows an example of the tuning device of FIG. 3 plugged into the TEC control board of FIG. 5.

[0014] FIG. 7 shows another view of the tuning device of FIG. 3 plugged into the TEC control board of FIG. 5.

[0015] FIG. 8 schematically illustrates an example of a drive circuit for the illumination assembly of FIG. 2.

[0016] FIG. 9 graphically illustrates a plot showing a half peak coefficient of variation (HPCV) before an oscillating wave signal is inserted into the drive circuit of FIG. 8.

[0017] FIG. 10 graphically illustrates a plot showing the HPCV after the oscillating wave signal is inserted into the drive circuit of FIG. 8.DETAILED DESCRIPTION

[0018] Various embodiments will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the claims attached hereto. Additionally, any examples set forth in thisspecification are not intended to be limiting and merely set forth some of the many possible embodiments for the appended claims.

[0019] FIG. 1 illustrates an example of a system 10 that can be used to perform flow cytometry. The system 10 includes a flow cytometer 100 and a workstation 110. In general, the flow cytometer 100 is an analytical instrument that detects physical and chemical properties of samples of cells or particles. In some examples, the flow cytometer 100 is designed to capture robust and high quality data for characterizing biologically relevant nanoparticles. The flow cytometer 100 is an instrument that provides simultaneous assessment of nanoparticle size, concentration, and cargo to understand biological mechanisms of action and nanoparticle origins. The flow cytometer 100 can collect data from millions of particles or cells in a matter of minutes for display in a variety of formats on a display monitor 114 of the workstation 110.

[0020] The flow cytometer 100 includes a housing 101 having a multi-carousel loader 104 that can receive containers of samples of cells and / or particles. In some examples, the containers hold nanoparticles such as extracellular vesicles (EVs). A user of the system 10 manually loads the containers into the multi-carousel loader 104. Once loaded therein, the flow cytometer 100 acquires the samples from the containers to perform flow cytometry experiments.

[0021] The workstation 110 connects to the flow cytometer 100 via a wired or wireless connection to receive data from the flow cytometer 100 for display on the display monitor 114. The workstation 1 10 includes one or more user input devices such as a mouse 116 and a keyboard 118 allowing a user of the system 10 to enter data and information, control the flow' cytometer 100, and alter the display of the data on the display monitor 114.

[0022] The workstation 110 further includes a computing device 112. In some examples, the workstation 110 utilizes the computing device 112 to process raw data received from the flow cytometer 100. Alternatively, or additionally, the flow' cytometer 100 can include a computing device to process data collected from flow cytometry. In such examples, the flow cytometer 100 sends processed data to the workstation 110 for display on the display monitor 114

[0023] FIG. 2 illustrates an example of an illumination assembly 200 inside the flow cytometer 100. The illumination assembly 200 includes one or more laser diodes 202. In the example illustrated in FIG. 2, the illumination assembly 200 includes a first laser diode 202a, a second laser diode 202b, and a third laser diode 202c. The first laserdiode 202a, the second laser diode 202b, and the third laser diode 202c each emit an excitation light beam for projection onto particles flowing through an interrogation zone in a flow chamber 204.

[0024] The first laser diode 202a, the second laser diode 202b, and the third laser diode 202c each emit an excitation light beam of a particular wavelength. As an illustrative example, the first laser diode 202a emits an excitation light beam in the red visible light spectrum (e.g., 625-825 nm). the second laser diode 202b emits an excitation light beam in the blue visible light spectrum (e g., 450-490 nm), and the third laser diode 202c emits an excitation light beam in the violet visible light spectrum (e.g., 300-450 nm).

[0025] In the example shown in FIG. 2, the first laser diode 202a, the second laser diode 202b, and the third laser diode 202c are arranged in parallel relative to one another. It should be understood that the number, the type, and the arrangement of the laser diodes 202 are not limited to the example shown and described herein, and may be changed as needed. For example, the system may include four, five, six. or any other suitable number of laser diodes.

[0026] The illumination assembly 200 further includes one or more dichroic mirrors 206. In the example show n in FIG. 2, the illumination assembly 200 includes a first dichroic mirror 206a, a second dichroic mirror 206b, and a third dichroic mirror 206c arranged between the laser diodes 202 and the flow chamber 204. The dichroic mirrors 206 are configured according to the w avelengths of the light beams emitted by the respective laser diodes 202. The dichroic mirrors 206 are each configured to reflect a light beam of a corresponding one of the laser diodes 202 and transmit the light beams of the other laser diodes. For example, the first dichroic mirror 206a reflects light of the wavelength emitted by the first laser diode 202a toward the flow chamber 204, the second dichroic mirror 206b reflects light of the wavelength emitted by the second laser diode 202b toward the flow' chamber 204 and transmits light of the wavelength emitted by the first laser diode 202a, and the third dichroic mirror 206c reflects light of the wavelength emitted by the third laser diode 202c toward the flowchamber 204 and transmits light of the wavelengths emitted by the first laser diode 202a and the second laser diode 202b.

[0027] The excitation light beams emitted by the laser diodes 202 are reflected by or transmitted through the dichroic mirrors 206 to form collinear beams. The collinear beams share an optical axis, and provide a confocal point of multiple light sources byfocusing on the same interrogation point. The dichroic mirrors 206 are adjustable in their positions or orientations, such that they can be used to adjust the position of the focus point of the light beams, especially, the position on a plane perpendicular to the optical axis.

[0028] The illumination assembly 200 further includes one or more lens assemblies 208. In the example shown in FIG. 2, the illumination assembly 200 includes a first lens assembly 208a, a second lens assembly 208b, and a third lens assembly 208c that are arranged between the respective laser diodes 202 and the respective dichroic mirrors 206.

[0029] The lens assemblies 208 are adjustable in their positions or orientations to adjust the position of the focus point of the excitation light beams, especially, the position on the plane perpendicular to the optical axis. Generally, the dichroic mirrors 206 can be used to roughly adjust the position of the focus point of the excitation light beams, whereas the lens assemblies 208 can be used to finely adjust the position of the focus point of the excitation light beams.

[0030] It should be understood that the number, the type, and the arrangement of the dichroic mirrors 206 and the lens assemblies 208 may be changed as needed, and are not limited to the example illustrated herein. Also, the dichroic mirrors 206 and the lens assemblies 208 can be replaced with other optical elements having similar functions.

[0031] The wavelengths of the excitation light beams emitted by the first laser diode 202a, the second laser diode 202b, and the third laser diode 202c are influenced by the temperature of the laser diodes. It is desirable to maintain a constant temperature for the first laser diode 202a, the second laser diode 202b, and the third laser diode 202c during operation of the flow cytometer 100 such that the wavelength of the excitation light beams emitted by the laser diodes are constant for recording consistent flow cy tometry experiments by the flow cytometer 100.

[0032] The illumination assembly 200 includes a thermoelectric cooler (TEC) control board 216 that regulates the temperatures of the first laser diode 202a, the second laser diode 202b, and the third laser diode 202c. The TEC control board 216 controls the temperature of the laser diodes 202 by delivering current and voltage to thermal elements such as Peltier coolers, heaters, or thermoelectric heat pumps, which are regulated by the TEC control board 216 based on temperature feedback readings from temperature sensors. Each of the first laser diode 202a, the second laser diode202b, and the third laser diode 202c can include a temperature sensor for providing the temperature feedback readings to the TEC control board 216. and a thermal element controlled by the TEC control board 216 for regulating the laser diode temperature.

[0033] Alignment verification of the illumination assembly 200 is typically performed to ensure quality7control of the flow cytometry experiments performed by the flow cytometer 100. In some instances, the alignment verification is performed on a daily basis. The alignment verification typically includes collecting control data from control beads such as fluorescent microspheres, and analyzing the control data to ensure that it is within a maximum value allowed for a half peak coefficient of variation (HPCV). Small HPCV values (e.g., less than 2%) indicate a proper alignment of the optical elements on the illumination assembly 200, whereas large HPCV values (e.g., greater than 2%) indicate misalignment of the optical elements.

[0034] When the control data is outside of the maximum value allowed for HPCV, the alignment verification returns an alignment error. Otherwise, when the control data is within the maximum value allowed for HPCV, the flow cytometer 100 passes the alignment verification, and the user can proceed to use the flow cytometer 100 to run a flow cytometry7experiment.

[0035] Large HPCV values can result from instability7of the excitation light beams emitted by the laser diodes 202 of the illumination assembly 200. Further, different laser diode temperatures can make alignment of the laser diodes 202 difficult such that the alignment verification returns an alignment error. Typically, the laser diodes 202 are replaced in order to correct the alignment error, which is costly and wastes resources. Given the foregoing, it is desirable to develop a technique that can be used to correct alignment errors of the laser diodes 202 of the illumination assembly 200 without replacing the laser diodes 202.

[0036] FIG. 3 shows an example of a tuning device 300 for tuning the illumination assembly 200. As will be described in more detail, the tuning device 300 can be used to tune the illumination assembly 200 such that it passes the alignment verification without replacing the first laser diode 202a. the second laser diode 202b. or the third laser diode 202c.

[0037] The tuning device 300 includes a body 302, and a cable tether 304 that extends from the body 302 and that tenninates in a first connector 306. The tuning device 300 further includes a power harness 308 that includes a second connector 310 on one end, and a power receptacle 311 on an opposite end. The power harness 308further includes a cable tether 312 that connects to internal electrical components housed inside the body 302 of the tuning device 300. As will be described in more detail, the second connector 310 plugs into a power receptacle of the TEC control board 216, and the power receptacle 311 receives a power harness of the flow cytometer 100. In this example, the cable tether 312 taps electrical voltage from the power harness of the flow cytometer 100 for supplying the electrical voltage to power the tuning device 300.

[0038] The tuning device 300 includes one or more switches 314 for adjusting the illumination assembly 200. In the example shown in FIG. 3, the tuning device 300 includes a first switch 314a for adjusting operation of the first laser diode 202a, a second switch 314b for adjusting operation of the second laser diode 202b. and a third switch 314c for adjusting operation of the third laser diode 202c. The number of switches 314 on the tuning device 300 may vary based on the number of laser diodes 202 on the illumination assembly 200.

[0039] The first switch 314a, the second switch 314b, and the third switch 314c are each adjustable between different temperature settings for respectively tuning the temperature of the first laser diode 202a, the temperature of the second laser diode 202b, and the temperature of the third laser diode 202c. As described above, the temperatures of the laser diodes 202 are regulated by the TEC control board 216. The tuning device 300 interfaces with the TEC control board 216 to adjust individually the temperatures of the first laser diode 202a, the second laser diode 202b, and / or the third laser diode 202c. As an illustrative example, the switches 314 are each adjustable between five different temperature value positions such as 20°C, 27°C, 35°C, 42°C, and 50°C.

[0040] FIG. 4 schematically illustrates an example of a method 400 of tuning the illumination assembly 200. The method 400 uses the tuning device 300 to correct alignment errors that can result from instability of the of the excitation light beams emitted by the laser diodes 202 and from the laser diode temperatures without replacing the laser diodes 202.

[0041] The method 400 includes an operation 402 of receiving an alignment error during alignment verification performed on the flow cytometer 100. The alignment error can result from instability of an excitation light beam and / or a laser diode temperature of a laser diode 202 on the illumination assembly 200. Operation 402 can include receiving an alignment error for the first laser diode 202a of the illuminationassembly 200. Alternatively, or additionally, operation 402 can include receiving an alignment error for the second laser diode 202b of the illumination assembly 200. Alternatively, or additionally, operation 402 can include receiving an alignment error for the third laser diode 202c of the illumination assembly 200. The alignment error received in operation 402 can be displayed on the display monitor 114 of the workstation 110.

[0042] The method 400 includes an operation 404 of installing the tuning device 300 in the flow cytometer 100. Operation 404 can include powering down the flow cytometer 100 and opening the housing 101 such as by removing a cover to access the illumination assembly 200.

[0043] FIG. 5 shows an example of the TEC control board 216 inside the flow cytometer 100. FIG. 6 shows an example of the tuning device 300 plugged into the TEC control board 216. FIG. 7 shows another view of the tuning device 300 plugged into the TEC control board 216. Referring now to FIGS. 5-7, operation 404 of the method 400 can include disconnecting a connector 322 of a power harness 324 from a power receptacle 320 of the TEC control board 216 (see FIG. 5). As an example, the power receptacle 320 can be Power IN JI 0 connector port.

[0044] Operation 404 can further include connecting the second connector 310 of the power harness 308 into the power receptacle 320 of the TEC control board 216, and connecting the connector 322 of the power harness 324 into the power receptacle 311 of the power harness 308 (see FIG. 6). In this manner, the power harness 308 of the tuning device 300 is connected between the power receptacle 320 and the power harness 324 of the TEC control board 216.

[0045] When installing the tuning device 300, the connector 322 of the power harness 324 of the flow cytometer 100 plugs into the power receptacle 311 of the power harness 308 of the tuning device 300. The second connector 310 of the tuning device 300 plugs into the pow er receptacle 320 of the TEC control board 216. The wires between the second connector 310 and the power receptacle 311 are straight through cables, and the cable tether 312 taps electrical power (e.g., 5V) from the power harness 324 of the flow cytometer 100. In this manner, the TEC control board 21 receives electrical power from the pow er harness 324, and the tuning device 300 receive electrical power (e.g., 5V) from the cable tether 312 for powering its operation.

[0046] Operation 404 can further include connecting the first connector 306 at the end of the cable tether 304 of the tuning device 300 to a second receptacle 318 of theTEC control board 216. As an example, the second receptacle 318 can be a 9-pin serial J12 connector port such that the first connector 306 of the tuning device 300 can be a DB9 (9-pin) connector. In some examples, the first connector 306 of the tuning device 300 is secured to the second receptacle 318 of the TEC control board 216 using one or more screws 307 (see FIG. 7).

[0047] When installed, the tuning device 300 should have the switches 314 set to a middle temperature value position (e.g.. 35°). which is a default temperature setting for the laser diodes 202. After, the tuning device 300 is installed, the flow cytometer 100 is powered on and a user or field technician can log into a system software on the workstation 110.

[0048] Referring back to FIG. 4, the method 400 includes an operation 406 of adjusting a position of a switch 314 on the tuning device 300 to adjust the laser diode temperature of at least one of the laser diodes 202. As discussed above, the switches 314 are each adjustable between five different temperature value positions such as 20°C, 27°C, 35°C, 42°C, and 50°C. As described above, the middle temperature value position (e.g., 35°) is a default temperature setting such that operation 406 includes adjusting the position of the switch 314 on the tuning device 300 to a position (e.g., 20°C or 27°C) that is less than the middle temperature value position, or to a position (e.g., 42°C or 50°C) that is greater than the middle temperature value position. In some examples, operation 406 includes adjusting the position of the switch 314 on the tuning device 300 to a lowest temperature value position (e.g., 20°C).

[0049] In alternative examples, the switches 314 on the tuning device 300 do not include a middle temperature value position that is a default temperature setting of the laser diodes 202 on the illumination assembly 200 because the flow cytometer 100 will high HPCV at the default temperature setting whenever the tuning device 300 is used on the flow cytometer 100. In such examples, each of the switches 314 on the tuning device 300 can have adjustable temperature value positions of 20°C, 25°C, 30°C, 40°C, and 45°C. In further examples, the tuning device 300 can include a logging function such that the tuning device 300 operates as a temperature logger.

[0050] Operation 406 can include adjusting the first switch 314a associated with the first laser diode 202a to a temperature value position (e.g., 20°C, 27°C, 42°C, or 50°C) other than the middle temperature value position (e.g., 35°C). As another example, operation 406 can include adjusting the second switch 314b associated with the second laser diode 202b to a temperature value position other than the middletemperature value position. As another example, operation 406 can include adjusting the third switch 314c associated with the third laser diode 202c to a temperature value position other than the middle temperature value position.

[0051] The method 400 includes an operation 408 of determining whether the half peak coefficient of variation (HPCV) for the laser diode 202 tuned by the adjustment of the switch 314 in operation 406 is less than the maximum value allowed for the HPCV. For example, operation 408 can include re-running the alignment verification on the flow cytometer 100.

[0052] When the HPCV for the laser diode 202 tuned by the adjustment of the switch 314 in operation 406 is not less the maximum value allowed for the HPCV such that alignment verification continues to return an alignment error (i. e. , "No" in operation 408), the method 400 includes returning to operation 406 to make another adjustment of the switch 314 for adjusting the laser diode. For example, when the switch 314 is first adjusted to a first temperature value position, operation 406 when repeated can include making another adjustment of the switch 314 to a different temperature value position. Operations 406, 408 can be repeated as many times as necessary to tune the illumination assembly 200 until the HPCV for the laser diode 202 is less than the maximum value allowed for the HPCV such that alignment verification on the flow cytometer 100 does not return an alignment error.

[0053] When the HPCV for the laser diode 202 tuned by the adjustment of the switch 314 in operation 406 is less than the maximum acceptable HPCV such that the alignment verification does not return an alignment error (i.e., ‘'Yes” in operation 408), the method 400 includes an operation 410 of closing the housing 101 of the flow cytometer 100. When an acceptable HPCV is obtained at both high temperature value positions (42°C and 50°C) and low temperature value positions (20 and 27 °C) on the switch 314, the lower temperature value position should be chosen because the laser diodes 202 have longer lifetime at lower temperatures.

[0054] FIG. 8 schematically illustrates an example of a drive circuit 800 for the illumination assembly 200. As shown in FIG. 8. the drive circuit 800 includes a direct current (DC) drive 802 for powering the laser diodes 202 of the illumination assembly 200. The drive circuit 800 further includes an oscillator 806 that inserts an oscillating wave signal into the drive circuit 800.

[0055] The oscillating wave signal provides a frequency modulation of the drive circuit to mitigate instability of the excitation light beams emitted by the laser diodes202 of the illumination assembly 200. In some examples, the oscillating wave signal is an alternating current (AC). In some further examples, the oscillating wave signal provides the frequency modulation between about 10 MHz and about 300 MHz.

[0056] As shown in FIG. 8, the oscillating wave signal is inserted into a bias tee circuit 804 connected to the DC drive 802 and to the laser diodes 202. The bias tee circuit 804 ensures that the oscillating wave signal does not interfere with the DC drive 802.

[0057] FIG. 9 graphically illustrates a plot 900 showing a half peak coefficient of variation (HPCV) before the oscillating wave signal is inserted into the drive circuit 800. FIG. 10 graphically illustrates a plot 1000 showing the HPCV after the oscillating wave signal is inserted into the drive circuit 800. In the example shown in FIG. 10, the oscillating wave signal has a frequency of 50 MHz at 10 volts. As shown in FIGS. 8 and 9, the oscillating wave signal significantly reduces variability of the wavelength emitted by the laser diodes 202. For example, the plot 900 shows the HPCV as having two peaks, whereas the plot 1000 shows the HPCV having a Gaussian shape due to less variability in the wavelength emitted by the laser diode 202.

[0058] The various embodiments described above are provided by way of illustration only and should not be construed to be limiting in any way. Various modifications can be made to the embodiments described above without departing from the true spirit and scope of the disclosure.

Claims

What is claimed is:

1. A method of tuning an illumination assembly of a flow cytometer, the method comprising: receiving a first alignment error for a first laser diode of the illumination assembly; installing a tuning device in the flow cytometer; and adjusting a first switch associated with the first laser diode.

2. The method of claim 1, further comprising: receiving a second alignment error for a second laser diode of the illumination assembly; adjusting a second switch associated with the second laser diode.

3. The method of claim 2, further comprising: receiving a third alignment error for a third laser diode of the illumination assembly; adjusting a third switch associated with the third laser diode.

4. The method of claim 3, wherein the first laser diode emits red visible light, the second laser diode emits blue visible light, and the third laser diode emits violet visible light, and wherein the illumination assembly directs the red visible light, the blue visible light, and the violet visible light for projection onto an interrogation zone inside the flow cytometer.

5. The method of claim 4, wherein the first switch, the second switch, and the third switch are each adjustable between five different temperature settings for respectively tuning the first laser diode, the second laser diode, and the third laser diode.

6. The method of any of claims 1-5, further comprising: inserting an oscillating wave signal into a drive circuit of the illumination assembly, the oscillating wave signal providing a frequency modulation of the drive circuit.

7. The method of claim 6, wherein the oscillating wave signal provides the frequency modulation between about 10 MHz and about 300 MHz.

8. The method of claim 6 or 7, wherein the oscillating wave signal is inserted into a bias tee circuit connected to a direct current drive and to the illumination assembly.

9. A device for tuning an illumination assembly of a flow cytometer, the device comprising: a connector for connecting to the illumination assembly; and one or more switches for adjusting one or more laser diodes of the illumination assembly, the one or more switches being adjustable between different settings for tuning each laser diode of the one or more laser diodes.

10. The device of claim 9, wherein the one or more switches include: a first switch for tuning a first laser diode of the illumination assembly; a second switch for tuning a second laser diode of the illumination assembly; and a third switch for tuning a third laser diode of the illumination assembly.

11. The device of claim 10, wherein the first laser diode emits red visible light, the second laser diode emits blue visible light, and the third laser diode emits violet visible light, and wherein the illumination assembly directs the red visible light, the blue visible light, and the violet visible light for projection onto an interrogation zone inside the flow cytometer.

12. The device of claim 10 or 11, wherein the first switch, the second switch, and the third switch are each adjustable between five different temperature settings for respectively tuning the first laser diode, the second laser diode, and the third laser diode.

13. The device of any of claims 9-12, wherein the connector plugs into a drive circuit of the illumination assembly for inserting an oscillating wave signal to provide a frequency modulation of the drive circuit.

14. The device of claim 13, wherein the oscillating wave signal provides the frequency modulation between about 10 MHz and about 300 MHz.

15. The device of claim 13 or 14, wherein the oscillating wave signal is inserted into a bias tee circuit connected to a direct current drive and to the one or more laser diodes of the illumination assembly.

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