Variable beam size moving through the homogenizer

Abstract

An ablation system for ablating materials may include a laser source, a set of homogenizing optics, and a homogenizing optics adjustment device. The laser source generates a laser beam. The set of homogenizing optics receives the laser beam and includes a first homogenizer and a second homogenizer. The homogenizing optics adjustment device carries the homogenizing optics and is configured to selectively adjust the position of at least one of the first and second homogenizers to change the size of the laser beam, wherein the change in the size of the laser beam changes the flux of the laser beam. The ablation system may be integrated into a laser ablation-based analytical system, wherein the laser ablation-based analytical system includes a spectrometer.

Description

[0001] Related applications

[0002] This application claims domestic priority to U.S. Provisional Application No. 62 / 978,516, filed February 19, 2020, entitled “VARIABLE BEAM SIZE VIA HOMOGENIZER MOVEMENT”. The contents of U.S. Provisional Application No. 62 / 978,516 are hereby incorporated herein by reference. Background Technology

[0003] Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) or laser ablation inductively coupled plasma optical emission spectrometry (LA-ICP-OES) can be used to analyze targets (e.g., solid or liquid targets). Typically, the target sample is provided to the analytical system in the form of an aerosol (i.e., a suspension of solid and possibly liquid particles and / or vapors in a carrier gas such as helium). This sample is usually generated by arranging the target in a laser ablation chamber, introducing a carrier gas flow into the chamber, and ablating a portion of the target using one or more laser pulses to produce a plume containing particles and / or vapors ejected from or otherwise generated from the target (hereinafter referred to as the “target”) suspended in the carrier gas. Entrained in the flowing carrier gas, the target is transported to the analytical system via a transfer conduit leading to a TCP torch, where it is ionized. The plasma containing ionized particles and / or vapor is then analyzed using analytical systems such as MS, OES, isotope ratio mass spectrometry (IRMS), or electrospray ionization (ESI) systems. Attached Figure Description

[0004] A detailed description is provided with reference to the accompanying drawings.

[0005] Figure 1 This is a schematic diagram of a laser ablation-based analysis system according to an exemplary embodiment of the present disclosure.

[0006] Figure 2A-2C yes Figure 1 The diagram shows a series of schematic representations of a laser source, a pair of homogenizing optical devices (a first homogenizer and a second homogenizer), and a homogenizing optical device adjustment device in a laser ablation-based analysis system. Figure 2A-2C The confocal position, minimum beam size position, and maximum beam size position associated with the homogenization optical device adjustment device are shown respectively.

[0007] Figure 3A and Figure 3B They are respectively available for Figure 2A-2C A schematic isometric view of the square array microlens and fly-eye microlens condenser of the homogenized optical device shown. Detailed Implementation

[0008] Several aspects of this disclosure will be described more fully below with reference to the accompanying drawings, which form part of this disclosure and illustrate exemplary features by way of illustration. However, these features may be embodied in many different forms and should not be construed as limited to the combinations described herein; rather, these combinations are provided so that this disclosure will be exhaustive and complete and will fully convey its scope.

[0009] Overview

[0010] Current technology in the laser ablation portion of laser ablation-based spectral measurement systems uses (e.g., in pairs) two fly-eye homogenizing (lens group) optics to homogenize the laser beam. This beam homogenization method has only been demonstrated for 193nm excimer laser ablation systems (i.e., ultraviolet (UV) lasers using compounds of inert gases, halogens, etc., as their laser media), and has only been used in higher-energy systems, such as those manufactured by Teledyne, Coherent, or Applied Spectra. It is understood that each of these companies uses a dual fly-eye homogenization method in its systems. None of them implements any method to move one of these devices to control the laser beam parameters and thereby change the operating parameters of the system.

[0011] In the development of high-energy ablation systems, it is clear that there are at least two main use cases that customers desire. One is to produce much larger ablation sites with moderate energy density, and the other is to produce smaller ablation sites with much higher energy density or energy fluence. In optics, (e.g., a laser pulse) fluence F is the light energy transferred per unit area. Its most commonly used unit is J / cm². 2 (Joules per square centimeter). To achieve very high energy density and meet the requirements of a large spot size, it has been found that in one embodiment, the energy density at the sample can be selectively increased or decreased by moving the first of two homogenizing optics in the system's beam array. In one embodiment, the optics adjustment system can be electrically powered. Such an electrically powered adjustment system can be controlled by software and has at least two modes (e.g., position / energy density).

[0012] From a purely optical perspective, this concept can be considered similar to a tunable telescope. However, for laser ablation targeting mass spectra, there has been no previous use of active optics to selectively increase or decrease energy density. Furthermore, there is no evidence that such tunable optics can be used in conventional ablation, photolithography, or micromachining.

[0013] Exemplary Implementation

[0014] Figure 1 A laser ablation-based analytical system 100 according to an exemplary embodiment of the present disclosure is shown. The laser ablation-based analytical system 100 may include an ablation system 105 for ablating a target (not shown) of sample material, wherein the ablation system 105 includes a laser source 110 (e.g., an excimer laser), a pair of homogenizing optics 112 (a first homogenizer 112A; and a second homogenizer 112B), homogenizing optics adjustment means 114, beam adjustment optics 116 (e.g., surfaces and / or windows for reducing aberrations and / or expanding reflections or partial reflections of the beam); a spectrometer 118 (e.g., an optical emission spectroscopy (OES) or mass spectrometry (MS) system) to allow chemical analysis of the laser-ablated sample (e.g., a sample ablated using the ablation system 105); and a computing system for controlling the operation of the entire system 100. An example of a general laser ablation-based analytical system is described in U.S. Patent Publication No. 2019 / 0371590A1, the contents of which are hereby incorporated herein by reference as well as this disclosure focuses on ablation system 105. While ablation system 105 is shown as part of laser ablation-based analytical system 100, it should be understood that laser ablation-based analytical system 105 can be used alone to ablate materials other than the sample material to be analyzed in and / or not used in the laser ablation-based analytical system. In one embodiment, spectrometer 118 may be configured to receive and analyze the laser-ablated material.

[0015] The first homogenizer 112A for receiving the laser beam from the ablation system 105 can be in the form of a first microlens array, and the second homogenizer 112B for receiving the laser beam refracted by the first homogenizer 112A can be in the form of a second microlens array. In one embodiment, the configuration of the first microlens array is the same as that of the second microlens array. In one embodiment, a given first homogenizer 112A and / or a given second homogenizer 112B can be in the form of a square microlens array 112(1), such as... Figure 3A As shown (e.g., a two-dimensional microlens array extending in latitude and longitude). In one embodiment, a given first homogenizer 112A and / or a given second homogenizer 112B may be in the form of a fly-eye microlens array 112(2), as Figure 3B As shown (e.g., a single assembly of bifacial cylindrical microlenses arranged in a one-dimensional array). It should be understood that other microlens array arrangements are possible (e.g., hexagonal or rectangular microlens arrays) and are within the scope of this disclosure.

[0016] The first homogenizer 112A and the second homogenizer 112B can be movably mounted relative to each other, such as Figure 2A-2C As shown (e.g., at least one of the first homogenizer 112A or the second homogenizer 112B may be selectively movable relative to the other). This selective movement of at least one of the first homogenizer 112A or the second homogenizer 112B relative to the other can be achieved using a homogenizing optics adjustment device 114. The homogenizing optics adjustment device 114 may be in the form of a mechanically adjustable carrier (e.g., rack and pinion; sliding mount, etc.). In one embodiment, the homogenizing optics adjustment device 114 may include a fixing device (not shown) for each of the first homogenizer 112A and the second homogenizer 112B and an adjustable mechanism (not shown) for selectively moving at least one of the first homogenizer 112A or the second homogenizer 112B relative to the other. In one embodiment, the homogenizing optics adjustment device 114 may allow precise movement of the first homogenizer 112A relative to the laser beam axis (parallel to it). The laser beam (unlabeled) generated by the laser source 110 can be guided to a pair of homogenizing optics 112 to adjust their size (as discussed in more detail later), and then continue to be adjusted by any beam of light optics 116 and finally impact the sample or other material to be ablated. Figure 2A-2C The confocal position, minimum beam size position, and maximum beam size position of this pair of homogenizing optics 112 are shown, as indicated by the positioning of the homogenizing optics adjustment device 114. In one embodiment, once the homogenizing optics 112 and any beam adjustment optics 116 are in place, the laser beam can strike and ablate the material / sample.

[0017] The homogenizing optics adjustment device 114 of the ablation system 105 can be electrically or non-electrically powered and can be positionally variable (i.e., thus allowing changes in the relative positioning between the first homogenizer 112A and the second homogenizer 112B). For example, once the first homogenizer 112A is moved, the beam size (e.g., beam diameter; or beam cross-section) at the aperture plane can be changed, resulting in a higher flux at the sample (ablation site). Because it is positionally variable, the beam size can be adjusted to any size within a range including the minimum and maximum beam sizes as needed. Adjustment between the confocal beam size and the minimum beam size can be considered as a first mode, where the beam size (e.g., beam cross-sectional area) is reduced but the energy density is increased compared to the energy density at the confocal position. Conversely, adjustment between the confocal beam size and the maximum beam size is used as a second mode, where the beam size (e.g., beam cross-sectional area) is increased but the energy density is decreased compared to the energy density at the confocal position. In another embodiment, the second homogenizer 112B may be movable via the homogenizing optics adjustment device 114 (instead of or in addition to the movement of the first homogenizer 112A) to facilitate changing the flux of the laser beam.

[0018] The energy density (e.g., fluence) of the laser beam generated by the combination of the laser source 110 of the ablation system 105, the pair of homogenizing optics 112 (first homogenizer 112A; and second homogenizer 112B), and the homogenizing optics adjustment device 114 can generally be expressed by the following equation:

[0019]

[0020] In the formula, E = laser energy (e.g., mJ).

[0021] A = Cross-sectional area of ​​the light beam

[0022] Energy density (e.g., J / cm³) 2 )

[0023] When the beam cross-section is circular, the energy density can be more specifically expressed by the following equation:

[0024]

[0025] In the formula, E = laser energy (e.g., mJ).

[0026] D = Beam diameter (e.g., cm)

[0027] Energy density (e.g., J / cm³) 2 )

[0028] When the beam cross-section is rectangular (e.g., a beam from an excimer laser), the energy density can be more specifically expressed by the following equation:

[0029]

[0030] In the formula, E = laser energy (e.g., mJ).

[0031] L = Length of the beam cross-section (e.g., cm)

[0032] W = beam cross-sectional width (e.g., cm)

[0033] Energy density (e.g., J / cm³) 2 )

[0034] The laser ablation-based analysis system 100 can be controlled by a computing system 120, which has components configured to execute from non-transitory media (e.g., storage media, such as flash drives, hard disk drives, solid-state drives, SD cards, optical discs, etc.). The computing system 120 can be connected to various components of the analysis system via direct connection or via one or more network connections (e.g., local area network (LAN), wireless local area network (WAN or WLAN), one or more hubs (e.g., USB hubs), etc.). For example, the computing system 120 can be communicatively coupled (e.g., hardwired or wireless) to controllable elements of a given laser ablation-based analysis system 100 (e.g., laser source 110, homogenizing optics adjustment device 114, beam adjustment optics 116, and / or spectrometer 118). Program instructions, when executed by a processor, can cause the computing system 120 to control the given laser ablation-based analysis system 100. In one embodiment, the program instructions form at least a portion of a software program executable by a processor. If the ablation system 105 is to be used alone, it should be understood that it can be controlled by a computing system similar to computing system 120.

[0035] A processor provides processing capabilities to a computing system and may include any number of processors, microcontrollers, or other processing systems, as well as resident or external memory for storing data and other information accessed or generated by the computing system 120. A processor is not limited by the materials forming it or the processing mechanisms employed therein; therefore, it can be implemented via semiconductors and / or transistors (e.g., integrated circuits (ICs)).

[0036] Non-transitory carrier media are examples of device-readable storage media that provide storage functionality to store various data (e.g., software programs, code segments, or program instructions) or other data associated with the operation of computing system 120 for instructing the processor and other components of the computing system to perform the techniques described herein. The carrier media may be integrated with a processor, a separate memory, or a combination of both. The carrier media may include, for example, removable and non-removable storage elements such as RAM, ROM, flash memory (e.g., SD card, mini SD card, micro SD card), magnetic, optical, USB storage devices, etc. In embodiments of computing system 120, the carrier media may include, for example, a removable ICC (integrated circuit card) memory provided by a SIM (Subscriber Identity Module) card, USIM (Universal Subscriber Identity Module) card, UICC (Universal Integrated Circuit Card), etc.

[0037] The computing system 120 may include one or more displays to show information to a user of the computing system 120. In embodiments, the displays may include CRT (cathode ray tube) displays, LED (light-emitting diode) displays, OLED (organic LED) displays, LCD (liquid crystal diode) displays, TFT (thin-film transistor) LCD displays, LEP (light-emitting polymer) or PLED (polymer light-emitting diode) displays, etc., configured to display text and / or graphical information, such as a graphical user interface. The displays may be backlit, allowing them to be viewed in dark or other low-light environments. The displays may be equipped with a touchscreen to receive input from the user (e.g., data, commands, etc.). For example, a user may operate the computing system 120 by touching the touchscreen and / or by performing gestures on the touchscreen. In some embodiments, the touchscreen may be a capacitive touchscreen, a resistive touchscreen, an infrared touchscreen, a combination thereof, etc. The computing system 120 may also include one or more input / output (I / O) devices (e.g., keypad, buttons, wireless input devices, thumbwheel input devices, trackpoint input devices, etc.). The I / O devices may include one or more audio I / O devices, such as microphones, speakers, etc.

[0038] The computing system 120 may also include a communication module representing communication functions, allowing the computing device to send / receive data between different devices (e.g., components / peripherals) and / or over one or more networks. The communication module may represent a variety of communication components and functions, including, but not limited to: a browser; a transmitter and / or receiver; a data port; software interfaces and drivers; a network interface; a data processing component; and so on.

[0039] One or more networks represent various communication paths and network connections that can be used individually or in combination to communicate between components of the laser ablation-based analysis system 100. Therefore, one or more networks can represent communication paths obtained using a single network or multiple networks. Furthermore, one or more networks represent various types of networks and connections envisioned, including but not limited to: the Internet: intranet; personal area network (PAN); local area network (LAN) (e.g., Ethernet); wide area network (WAN); satellite network; cellular network; mobile data network; wired and / or wireless connection; and so on. Examples of wireless networks include, but are not limited to: networks configured for communication according to: one or more standards of the Institute of Electrical and Electronics Engineers (IEEE), such as 802.11 or 802.16 (Wi-Max) standards; Wi-Fi standards issued by the Wi-Fi Alliance; Bluetooth standards issued by the Bluetooth Special Interest Group; and so on. Wired communication, such as via Universal Serial Bus (USB), Ethernet, serial connections, etc., is also envisioned.

[0040] The computing system 120 is described as including a user interface that may be stored in memory (e.g., a carrier medium) and executed by a processor. This user interface represents the functionality to display information and data to a user of the computing system via a display control. In some embodiments, the display may not be integrated into the computing system but may be externally connected using a Universal Serial Bus (USB), Ethernet, serial connection, etc. The user interface can provide functionality that allows a user to interact with one or more applications of the computing system by providing input (e.g., sample identity, desired dilution factor, standard identity, eluent identity / location, fluid addition flow rate, etc.) via a touchscreen and / or I / O devices. For example, the user interface may result in the generation of an application programming interface (API) to expose functionality to an online dilution control module, thereby configuring the application for display on a monitor or in combination with another display. In embodiments, the API may further expose functionality to configure the online dilution control module, thereby allowing a user to interact with the application by providing input via a touchscreen and / or I / O devices to provide the desired dilution factor for analysis.

[0041] In this implementation, the user interface may include a browser. The browser enables the computing device to display and interact with content such as web pages on the World Wide Web, web pages provided by web servers in a private network, etc. The browser can be configured in various ways. The browser may be a web browser suitable for use by fully-resourced devices with ample memory and processor resources (e.g., smartphones, personal digital assistants (PDAs), etc.).

[0042] Generally, any functionality described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), manual processing, or a combination of these methods. As used herein, the terms "module" and "function" generally refer to software, firmware, hardware, or a combination thereof. For example, communication between components in a laser ablation-based analysis system 100 can be wired, wireless, or some combination thereof. Program code can be stored in one or more device-readable storage media, examples of which are non-transitory carrier media associated with a computing system.

[0043] Although the subject matter has been described in language specific to structural features and / or methodological behavior, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or behaviors described above. Rather, the specific features and actions described above are disclosed as exemplary forms for implementing the claims.

Claims

1. An ablation system, comprising: A laser source used to generate a laser beam; A set of homogenizing optical devices for receiving the laser beam, the homogenizing optical devices including a first homogenizer and a second homogenizer; A homogenizing optical device adjustment device, the homogenizing optical device adjustment device carrying the homogenizing optical device, the homogenizing optical device adjustment device being configured to selectively adjust the position of at least one of a first homogenizer and a second homogenizer relative to the other to change the size of the laser beam, the change in the size of the laser beam changing the flux of the laser beam, the laser beam being configured to ablate material as it passes through the first homogenizer and the second homogenizer; as well as A computing system communicatively connected to the homogenizing optics adjustment device, the computing system being configured to cause the homogenizing optics adjustment device to adjust the position of at least one of the first homogenizer and the second homogenizer relative to the other according to a first mode and a second mode of the ablation system, wherein the first mode is configured to adjust the size of the laser beam between a confocal beam size and a minimum beam size, and the second mode is configured to adjust the size of the laser beam between the confocal beam size and a maximum beam size.

2. The ablation system as described in claim 1, wherein, The size of the laser beam can be adjusted to any size within a range including the minimum and maximum beam sizes.

3. The ablation system as described in claim 1, wherein, The position of the first homogenizer is adjustable.

4. The ablation system as described in claim 1, wherein, The first homogenizer and the second homogenizer each include a microlens array.

5. The ablation system as described in claim 1, wherein, The ablation system is integrated into a laser ablation-based analysis system, which includes a spectrometer configured to receive and analyze the ablated material.

6. The ablation system as claimed in claim 1, wherein, The homogenizing optical device adjustment device is configured to selectively adjust the position of at least one of the first homogenizer and the second homogenizer relative to the other to increase the cross-sectional area of ​​the laser beam and correspondingly reduce the flux of the laser beam.

7. An ablation system, comprising: A laser source used to generate a laser beam; A set of homogenizing optical devices for receiving the laser beam, the homogenizing optical devices including a first homogenizer and a second homogenizer; A homogenizing optical device adjustment device, the homogenizing optical device adjustment device carrying a first homogenizer and a second homogenizer, the homogenizing optical device adjustment device being configured to selectively adjust the position of at least one of the first homogenizer and the second homogenizer relative to the other to change the cross section of the laser beam, the laser beam being configured to ablate a sample after passing through the first homogenizer and the second homogenizer; as well as A computing system communicatively connected to the homogenizing optics adjustment device, the computing system being configured to cause the homogenizing optics adjustment device to adjust the position of at least one of the first homogenizer and the second homogenizer relative to the other according to a first mode and a second mode of the ablation system, wherein the first mode is configured to adjust the size of the laser beam between a confocal beam size and a minimum beam size, and the second mode is configured to adjust the size of the laser beam between the confocal beam size and a maximum beam size.

8. The ablation system as claimed in claim 7, wherein, The cross-section of the beam is adjustable within a range including the minimum and maximum beam cross-sections.

9. The ablation system as claimed in claim 7, wherein, The position of the first homogenizer is adjustable.

10. The ablation system of claim 7, wherein, At least one of the first homogenizer or the second homogenizer includes a microlens array.

11. The ablation system of claim 7, wherein, The ablation system is integrated into a laser ablation-based analysis system.

12. The ablation system of claim 11, wherein, The laser ablation-based analysis system includes a spectrometer configured to receive and analyze the ablated sample.

13. The ablation system of claim 7, wherein, The homogenizing optical device adjustment device is configured to selectively adjust the position of at least one of the first homogenizer and the second homogenizer relative to the other to increase the cross-section of the laser beam and correspondingly decrease the flux of the laser beam.

14. The ablation system of claim 7, wherein, The homogenizing optical device adjustment device is configured to selectively adjust the position of at least one of the first homogenizer and the second homogenizer relative to the other to reduce the cross-section of the laser beam and correspondingly increase the flux of the laser beam.

15. An analysis system based on laser ablation, comprising: A laser source used to generate a laser beam; A set of homogenizing optical devices for receiving the laser beam, the homogenizing optical devices including a first homogenizer and a second homogenizer; A homogenizing optical device adjustment device, the homogenizing optical device adjustment device carrying a first homogenizer and a second homogenizer, the homogenizing optical device adjustment device being configured to selectively adjust the position of at least one of the first homogenizer and the second homogenizer relative to the other to change the size of the laser beam, the laser beam being configured to ablate material after passing through the first homogenizer and the second homogenizer; A computing system communicatively connected to the homogenizing optics adjustment device, the computing system being configured to cause the homogenizing optics adjustment device to adjust the position of at least one of the first homogenizer and the second homogenizer relative to the other according to a first mode and a second mode of the ablation system, wherein the first mode is configured to adjust the size of the laser beam between a confocal beam size and a minimum beam size, and the second mode is configured to adjust the size of the laser beam between the confocal beam size and a maximum beam size; as well as A spectrometer configured to receive and analyze ablated materials.

16. The laser ablation-based analysis system as described in claim 15, wherein, The size of the laser beam can be adjusted within a range including a minimum beam size and a maximum beam size.

17. The laser ablation-based analysis system as described in claim 15, wherein, The first homogenizer and the ablation second homogenizer each include a microlens array.

18. The laser ablation-based analysis system as described in claim 17, wherein, The microlens array includes either a square microlens array or a fly-eye microlens array.

19. The laser ablation-based analysis system as described in claim 15, wherein, The homogenizing optical device adjustment device is configured to selectively adjust the position of at least one of the first homogenizer and the second homogenizer relative to the other to increase the size of the laser beam and correspondingly decrease the flux of the laser beam.

20. The laser ablation-based analysis system as described in claim 15, wherein, The homogenizing optical device adjustment device is configured to selectively adjust the position of at least one of the first homogenizer and the second homogenizer relative to the other to reduce the size of the laser beam and correspondingly increase the flux of the laser beam.

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