Novel laser-driven plasma light source

Abstract

The invention provides a novel laser-driven plasma light source, and relates to the technical field of plasma light sources, the laser wavelength of the light source and the numerical aperture of a light beam are adjustable, and the laser beam can be automatically focused. Comprising a near-infrared semiconductor laser module, a light path system, a xenon lamp system, a wavelength control system, a diaphragm driving control system, a focus self-positioning system and an upper computer control system. The temperature and current of the semiconductor laser can be accurately regulated and controlled, so that the wavelength of the semiconductor laser is accurately controlled, and the light emitting stability of the laser-driven plasma light source is improved.

Description

Technical Field

[0001] The invention relates to the technical field of plasma light sources, and in particular to a novel laser-driven plasma light source, wherein the laser wavelength and the numerical aperture of the light beam of the light source are adjustable, and the laser beam can be automatically focused. Background Art

[0002] With the development of science and technology, ultra-bright broadband light sources are one of the necessary devices, whether in the field of life sciences or semiconductor detection. At present, common broadband light sources include electroluminescent light sources such as deuterium lamps, tungsten lamps, and xenon lamps. However, these traditional electroluminescent light sources usually use electrode coupling to generate plasma. Due to the high temperature ablation of the electrode, there are great limitations in brightness, stability, UV wavelength coverage and life. Laser-driven plasma light source is a light source that uses laser-driven plasma luminescence technology. Its working principle is to use a continuous laser beam to maintain plasma near the focus, thereby generating a high-brightness broadband spectrum. As an advanced light source, laser-driven plasma light source has the characteristics of high stability, wide spectrum and high brightness, and has high and wide application value. For example, semiconductor surface high-sensitivity defect detection based on LSP deep ultraviolet radiation, monochromator light source, hyperspectral imaging, optical sensors, life science and biological imaging, etc. However, the luminescence performance of laser-driven plasma light source is still restricted by many aspects, such as the wavelength, power and other performance stability of the laser used to maintain the plasma, and the numerical aperture of the laser beam. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention proposes a novel laser-driven plasma light source.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A novel laser-driven plasma light source, characterized in that it includes: a near-infrared semiconductor laser module, an optical path system, a xenon lamp system, a wavelength control system, an aperture drive control system, a focus self-positioning system and a host computer control system;

[0006] The light outlet of the near-infrared semiconductor laser module is connected with an optical fiber for outputting a near-infrared laser beam; the semiconductor laser module is connected with a wavelength control system;

[0007] The optical path system includes a collimating beam expansion system, an adjustable diaphragm, a focusing system and a transflective mirror. The near-infrared laser beam is subjected to beam shaping after entering the optical path system. The near-infrared laser beam is converted into a first parallel beam through the collimating beam expansion system. The first parallel beam is adjusted to a second parallel beam through the adjustable diaphragm, and the adjustable diaphragm is connected to an diaphragm driving control system. The second parallel beam is converged into a beam through the focusing system. The beam is divided into two beams through the transflective mirror, one of which is a strong transmission beam that continues to move along the original optical path, and the other is reflected to form a weak reflection beam. The strong transmission beam is focused on the center position of two electrodes of the xenon lamp system to excite and maintain the continuous emission of plasma. The weak reflection beam is focused on the focus self-positioning system and fed back to the focusing system through the focus self-positioning system. The wavelength control system, the diaphragm driving control system and the focus self-positioning system are all connected to a host computer control system, and the host computer control system is responsible for monitoring and processing of the entire system and user interaction.

[0008] The wavelength control system is composed of a power module, a temperature control module, a wavelength collection module and a feedback control module. The feedback control module collects wavelength data from the wavelength collection module to feedback and control the power module and the temperature control module, thereby achieving precise adjustment of the wavelength.

[0009] The power module consists of a constant current source module, a signal sampling and processing module, and a closed-loop control module, and is used for precise adjustment of the working current of the semiconductor laser module. The constant current source module injects a stable current into the semiconductor laser module, the signal sampling and processing module samples and processes the output signal of the semiconductor laser module in real time, and the closed-loop control module calculates the control quantity according to the signal sampled by the signal sampling and processing module through methods such as the PI adjustment algorithm, and adjusts the output current of the constant current source module through methods such as PWM to achieve precise control of the output power of the semiconductor laser module. The temperature control module consists of a refrigeration module, a temperature sensing module, and a feedback control module, and is used for precise adjustment of the working temperature of the semiconductor laser module. The refrigeration module is used for temperature adjustment of the semiconductor laser module, the temperature sensing module is used for temperature monitoring of the semiconductor laser module, and the data is fed back to the feedback control module. The feedback control module adjusts the working state of the refrigeration module according to the feedback information to maintain the temperature range required by the semiconductor laser module. The wavelength collection module is used to collect the wavelength of the output beam when the semiconductor laser module is working.

[0010] Among them, the aperture drive control system consists of a drive control module, an adjustable aperture execution module and a feedback detection module, which is used to drive and control the aperture size of the adjustable aperture.

[0011] The drive control module automatically analyzes and processes according to the preset algorithm, generates the corresponding control signal and sends it to the adjustable iris execution module. The adjustable iris execution module adjusts the aperture size of the adjustable iris in real time to ensure that the performance index of the light beam always meets the system requirements. The feedback detection module monitors and collects data on the position information and aperture size of the adjustable iris execution module in real time, and feeds back the sampled signal to the drive control module in real time.

[0012] The focus self-positioning system is composed of a focus system driving module, a light spot detection module and a feedback control module, and is used for self-calibration of the focus position.

[0013] The focusing system driving module is used to drive and change the position of the focusing system, including the front and rear position and the pitch angle. Through these precise position adjustments, the propagation path and the focus position of the light beam can be effectively controlled. The spot detection module is used to detect the spot size and the spot position at the focus of the weak reflection light beam. The feedback control module collects data from the spot detection module and is used to feedback control the focusing system driving module, thereby determining the spot size and position detected by the spot detection module. The reflective mirror makes the weak reflection light beam and the strong transmission light beam have a mirror-symmetrical relationship. The spot size and the spot position at the focus of the weak reflection light beam can be used to determine the spot size and the spot position of the focus of the strong transmission light beam, so that the strong transmission light beam is exactly focused on the center position of the two electrodes of the xenon lamp system.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] (1) The present invention can achieve precise control of the temperature and current of a semiconductor laser, thereby achieving precise control of the wavelength of the semiconductor laser and improving the luminescence stability of the laser-driven plasma light source.

[0016] (2) The present invention realizes controllable adjustment of the aperture of the diaphragm, which can effectively control the numerical aperture of the focused light beam and improve the luminous brightness of the laser-driven plasma light source.

[0017] (3) The present invention can realize accurate correction and positioning of the focal position of the plasma laser beam through the focus self-positioning system, thereby improving the luminous stability of the laser-driven plasma light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of a novel laser-driven plasma light source of the present invention.

[0019] Figure 2 Schematic diagram of the wavelength control system of the present invention.

[0020] Figure 3 It is a schematic diagram of the aperture drive control system and the focus self-positioning system of the present invention.

[0021] In the figure, the reference numerals are: semiconductor laser module 1, optical fiber 2, near-infrared laser beam 31, first parallel beam 32, second parallel beam 33, converging beam 34, transmitted beam 35, reflected beam 36, optical path system 4, collimation and beam expansion system 41, adjustable aperture 42, focusing system 43, transflective mirror 44, xenon lamp system 5, plasma 51, wavelength control system 6, power supply module 61, temperature control module 62, wavelength collection module 63, feedback control module 64, constant current source module 610, signal sampling and processing module 611, closed-loop control module 612, refrigeration module 620, temperature sensing module 621, feedback control module 622, aperture drive control system 7, drive control module 71, adjustable aperture execution module 72, feedback detection module 73, focus self-positioning system 8, focusing system drive module 81, spot detection module 82, feedback control module 83, host computer control system 9. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other. To achieve the above-mentioned purpose, the present invention adopts the following technical scheme.

[0023] like Figure 1 As shown, the present invention provides a novel laser-driven plasma light source, comprising: a semiconductor laser module 1, an optical path system 4, a xenon lamp system 5, a wavelength control system 6, an aperture drive control system 7, a focus self-positioning system 8 and a host computer control system 9; wherein the semiconductor laser module 1 is a near-infrared semiconductor laser.

[0024] The light outlet of the semiconductor laser module 1 is connected to an optical fiber 2 for transmitting a near-infrared laser beam 31. The wavelength of the near-infrared laser beam 31 is near 980 nm in the near infrared. The near-infrared laser beam 31 is shaped by the optical path system 4 and focused on the center of the xenon lamp system 5 to maintain the continuous emission of the plasma 51 in the center of the xenon lamp system 5.

[0025] The optical path system 4 includes a collimating and expanding system 41, an adjustable aperture 42, a focusing system 43 and a transflective mirror 44. The collimating and expanding system 41 is used to collimate and expand the near-infrared laser beam 31 into a first parallel beam 32, the adjustable aperture 42 is used to adjust the first parallel beam 32 into a second parallel beam 33, the focusing system 43 is used to convert the second parallel beam 33 into a convergent beam 34, and the transflective mirror 44 is used to divide the convergent beam 34 into two beams, one of which is a strong transmission beam 35 that continues to move along the original optical path, and the other is reflected to form a weak reflection beam 36. The intensity of the strong transmission beam 35 must be sufficient to excite and maintain the continuous luminescence of the plasma 51, and the intensity of the weak reflection beam 36 is related to the focus self-positioning system 8, and its intensity can be detected by the focus self-positioning system 8 without damaging the focus self-positioning system 8.

[0026] Wavelength control system 6 Figure 2 As shown, it is composed of a power supply module 61, a temperature control module 62, a wavelength collection module 63 and a feedback control module 64.

[0027] The power supply module 61 is composed of a constant current source module 610, a signal sampling and processing module 611 and a closed-loop control module 612, and is used for precise adjustment of the working current of the semiconductor laser module 1. The constant current source module 610 injects a stable current into the semiconductor laser module 1, the signal sampling and processing module 611 samples and processes the output signal of the semiconductor laser module 1 in real time, and the closed-loop control module 612 calculates the control amount according to the signal sampled by the signal sampling and processing module 611 through methods such as the PI adjustment algorithm, and adjusts the output current of the constant current source module 610 through methods such as PWM to achieve precise control of the output power of the semiconductor laser module 1, thereby achieving wavelength control of the semiconductor laser module 1. Since the wavelength of the semiconductor laser module 1 is closely related to the working current, the wavelength control of the semiconductor laser module 1 can be achieved by controlling the working current.

[0028] The temperature control module 62, which is composed of a refrigeration module 620, a temperature sensing module 621 and a feedback control module 622, is used for precise adjustment of the working temperature of the semiconductor laser module 1. The refrigeration module 620 is used for adjusting the temperature of the semiconductor laser module 1, and the temperature sensing module 621 is used for monitoring the temperature of the semiconductor laser module 1 and feeding back the data to the feedback control module 622. The feedback control module 622 adjusts the working state of the refrigeration module 620 according to the feedback information to maintain the semiconductor laser module 1 within the set temperature range, thereby achieving wavelength control of the semiconductor laser module 1. Since the wavelength of the semiconductor laser module 1 is closely related to the working temperature, the wavelength control of the semiconductor laser module 1 can be achieved by controlling the temperature.

[0029] The wavelength collection module 63 is used to collect the wavelength of the output light beam 31 when the semiconductor laser module 1 is working. The feedback control module 64 collects the wavelength data of the wavelength collection module 63 and feeds it back to the power module 61 and the temperature control module 62, and realizes the precise control of the output wavelength of the semiconductor laser module 1 by regulating the working temperature and the working current.

[0030] Aperture drive control system 7 Figure 3 As shown, it is composed of a driving control module 71, an adjustable iris execution module 72 and a feedback detection module 73, and is used to drive and control the aperture size of the adjustable iris 42. The driving control module 71 automatically analyzes and processes according to a preset algorithm, generates a corresponding control signal and sends it to the adjustable iris execution module 72, and the adjustable iris execution module 72 adjusts the aperture size of the adjustable iris 42 in real time to ensure that the performance index of the light beam always meets the requirements of the system. The feedback detection module 73 monitors and collects data on the position information and aperture size of the adjustable iris execution module 72 in real time, and feeds back the sampled signal to the driving control module 71 in real time. The aperture size of the adjustable iris 42 is closely related to the numerical aperture of the transmitted light beam 35. If the aperture size of the adjustable iris 42 becomes larger, the numerical aperture of the transmitted light beam 35 will also become larger; conversely, if the aperture size of the adjustable iris 42 becomes smaller, the numerical aperture of the transmitted light beam 35 will also become smaller. The numerical aperture of the transmitted light beam 35 represents the size of the light cone half angle. Generally, a transmitted light beam with a larger numerical aperture can converge to the laser focus faster, produce a small focal area, keep the plasma spherical, and emit higher brightness light.

[0031] Focus self-positioning system 8 Figure 3 As shown, it is composed of a focusing system driving module 81, a spot detection module 82, and a feedback control module 83. The focusing system driving module 81 is used to drive and change the position of the focusing system 43, including the front and rear position and the pitch angle. The spot detection module 82 is used to detect the spot size and spot position at the focus of the weak reflection light beam 36. The feedback control module 83 collects data from the spot detection module 82 and is used to feedback control the focusing system driving module 81 to obtain the position and pitch angle of the focusing system 43 corresponding to the optimal spot value. The reflective mirror 44 can make the weak reflection light beam 36 and the strong transmission light beam 35 mirror-symmetrical. Therefore, the spot size and spot position at the focus of the strong transmission light beam 35 can be determined by the spot size and spot position at the focus of the weak reflection light beam 36, so that the strong transmission light beam 35 is just focused on the center position of the two electrodes of the xenon lamp system 5. The spot detection module 82 can be a CCD detection camera. When the weak reflection light beam 36 irradiates the CCD detection camera, it must be ensured that the camera will not be damaged, so the proportion of the reflection light beam 36 must be very small.

[0032] The host computer control system 9 integrates and controls the data of the wavelength control system 6, the aperture drive control system 7 and the focus self-positioning system 8, and is responsible for the monitoring and processing of the entire system and user interaction.

[0033] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A new type of laser driven plasma light source, characterized in that: include: Near-infrared semiconductor laser module, optical path system, xenon lamp system, wavelength control system, aperture drive control system, focus self-positioning system and host computer control system; The light outlet of the near-infrared semiconductor laser module is connected with an optical fiber for outputting a near-infrared laser beam; the semiconductor laser module is connected with a wavelength control system; The optical path system comprises a collimating beam expansion system, an adjustable diaphragm, a focusing system and a transflective mirror. The near-infrared laser beam is subjected to beam shaping after entering the optical path system. The near-infrared laser beam is converted into a first parallel beam through the collimating beam expansion system. The first parallel beam is adjusted to a second parallel beam through the adjustable diaphragm, and the adjustable diaphragm is connected to an diaphragm driving control system. The second parallel beam is converged into a beam through the focusing system. The beam is divided into two beams through the transflective mirror, one of which is a strong transmission beam that continues to move forward along the original optical path, and the other is reflected to form a weak reflection beam. The strong transmission beam is focused on the center position of two electrodes of the xenon lamp system to excite and maintain the continuous luminescence of the plasma. The weak reflection beam is focused on the focus self-positioning system and fed back to the focusing system through the focus self-positioning system. The wavelength control system, the diaphragm driving control system and the focus self-positioning system are all connected to a host computer control system.

2. A novel laser driven plasma light source according to claim 1, characterized in that: The wavelength control system is composed of a power supply module, a temperature control module, a wavelength collection module and a feedback control module; The power supply module is composed of a constant current source module, a signal sampling and processing module and a closed-loop control module, and is used to adjust the working current of the semiconductor laser module; The constant current source module injects a stable current into the semiconductor laser module, the signal sampling and processing module samples and processes the output signal of the semiconductor laser module in real time, and the closed-loop control module calculates the control amount through methods such as PI adjustment algorithm based on the signal sampled by the signal sampling and processing module, and adjusts the output current of the constant current source module through PWM to achieve control of the output power of the semiconductor laser module.

3. A novel laser driven plasma light source according to claim 2, characterized in that: The temperature control module is composed of a refrigeration module, a temperature sensing module and a feedback control module, and is used to adjust the operating temperature of the semiconductor laser module; The refrigeration module is used for adjusting the temperature of the semiconductor laser module; the temperature sensing module is used for monitoring the temperature of the semiconductor laser module and feeding back data to the feedback control module, and the feedback control module adjusts the working state of the refrigeration module according to the feedback information to maintain the semiconductor laser module within a set temperature range.

4. A novel laser driven plasma light source according to claim 2, characterized in that: The wavelength collection module is used to collect the wavelength of the output light beam when the semiconductor laser module is working.

5. A novel laser driven plasma light source according to claim 2, characterized in that: The feedback control module is used to feedback and control the power module and the temperature control module by collecting the wavelength data of the wavelength collection module.

6. The novel laser driven plasma light source according to claim 1, characterized in that: The aperture drive control system is used to drive and control the light aperture size of the adjustable aperture.

7. The novel laser driven plasma light source according to claim 1, characterized in that: The focus self-positioning system is composed of a focus system driving module, a light spot detection module and a feedback control module.

8. The novel laser driven plasma light source according to claim 7, characterized in that: The focusing system driving module is used to drive and change the position of the focusing system, including the front and rear position and the pitch angle.

9. The novel laser driven plasma light source according to claim 7, characterized in that: The light spot detection module is used to detect the light spot size and light spot position at the focus of the weak reflection light beam.

10. The novel laser driven plasma light source according to claim 7, characterized in that: The feedback control module collects data from the light spot detection module to feedback control the focusing system driving module.

11. The novel laser driven plasma light source according to claim 1, characterized in that: The reflective mirror makes the weak reflected light beam and the strong transmitted light beam in a mirror-symmetrical relationship, and determines the spot size and spot position of the focus of the strong transmitted light beam through the spot size and spot position at the focus of the weak reflected light beam, so that the strong transmitted light beam is focused on the center position of the two electrodes of the xenon lamp system.

12. The novel laser driven plasma light source according to claim 6, characterized in that: The aperture drive control system consists of a drive control module, an adjustable aperture execution module and a feedback detection module. The drive control module generates a corresponding control signal and sends it to the adjustable aperture execution module. The adjustable aperture execution module adjusts the aperture size of the adjustable aperture in real time. The feedback detection module monitors and collects data on the position information and aperture size of the adjustable aperture execution module in real time and feeds back the sampled signal to the drive control module in real time.

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