A high-precision optical material scattering and absorption loss coefficient testing system and method

Abstract

The embodiment of the present application discloses a high-precision optical material scattering and absorption loss coefficient testing system and method. In a specific embodiment, the testing system comprises a laser, a first laser power meter, an integrating sphere and a photodetector, the integrating sphere is provided with an entrance hole, an exit hole and a detection hole, two mirrors with mirror surfaces are arranged in the integrating sphere, a medium to be tested is arranged between the two mirrors, the first laser power meter is used for receiving laser emitted through the exit hole, and the photodetector is used for detecting scattered light in the integrating sphere. In the embodiment, the two mirrors are arranged on the surfaces of the medium to be tested, a self-reproducing enhanced cavity is formed between the two mirrors, the transmission and reflection of laser between the two mirrors are controlled, the multi-pass transmission of tunable laser in the medium is realized, the scattering and absorption loss of the medium to be tested is increased by orders of magnitude, and the calculation precision of each coefficient is improved.

Description

Technical Field

[0001] This invention relates to the field of optical material characterization and evaluation. More specifically, it relates to a high-precision system and method for testing the scattering and absorption loss coefficients of optical materials. Background Technology

[0002] Currently, all-solid-state lasers are widely used in various fields, including industry, medicine, and scientific research. The working medium of a laser is a key component in laser generation, and its optical properties directly affect important parameters such as output power, wavelength, and beam quality. Therefore, research and development of laser working media are of great significance for improving laser performance and applications.

[0003] Modern industry and scientific research require the manufacture of high-precision optical components and systems, which necessitates a thorough understanding and evaluation of the optical properties of materials. Lasers, as a crucial application, require accurate testing and evaluation of the optical properties of their media to improve their performance and stability. Laser absorption and the scattering coefficient of the test medium are important parameters of a material's optical properties and key indicators of its suitability. Therefore, developing an efficient and high-precision testing device for the scattering and absorption loss coefficients of optical materials is of great significance for laser design and manufacturing.

[0004] Traditional methods for testing the laser absorption and scattering coefficient of the test medium mainly include laser transmission, laser reflection, and laser scattering methods. However, these methods have different drawbacks, such as lack of accuracy in test results, long testing time, and the need for complex equipment, which limits their application in actual production.

[0005] The existing Chinese patent document with application number CN102890071A, entitled "A Device for Measuring the Scattering Coefficient and Absorption Coefficient of a Laser Working Medium", discloses a device for measuring the scattering coefficient and absorption coefficient of a medium under test. The device consists of a test laser, an integrating sphere, a photodetector, a laser power meter, and an oscilloscope. The test laser emitted by the test laser is incident through the entrance aperture and perpendicularly incident on one end face of the medium under test, and exits from the other end face and the exit aperture of the medium under test. The loss coefficient of the medium under test during one-way transmission is obtained by using the measured values ​​of the total transmittance and scattering rate of the medium under test, as well as the calculation formulas for the scattering coefficient and absorption coefficient.

[0006] However, in this device, the laser is transmitted in a single path through the laser material, making it difficult to achieve high-precision measurement of the absorption and scattering of the test medium with extremely low optical loss.

[0007] In summary, during the process of realizing this invention, the inventors discovered at least the following problems in the prior art: the accuracy of the prior art in measuring the absorption coefficient and scattering coefficient of the test medium with extremely low optical loss is low. Summary of the Invention

[0008] The purpose of this invention is to provide a high-precision optical material scattering and absorption loss coefficient testing system and method that sets two mirrors with opposing surfaces on both sides of a medium inside an integrating sphere to form a self-reproducing enhancement cavity, thereby realizing multi-path transmission of laser within the medium, in order to solve at least one of the problems existing in the prior art.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] The first aspect of the present invention provides a high-precision optical material scattering and absorption loss coefficient testing system, the testing system comprising a laser, a first laser power meter, an integrating sphere, a medium under test, and a photodetector;

[0011] The integrating sphere contains two mirrors with their mirror surfaces facing each other; the medium to be measured can be placed between the two mirrors.

[0012] The integrating sphere is provided with an entrance aperture, an exit aperture, and a detection aperture;

[0013] The positions of the light entrance aperture, the reflector, and the light exit aperture are configured such that the laser light entering through the light entrance aperture is reflected multiple times by the reflector and then exits through the light exit aperture.

[0014] The first laser power meter is used to receive the laser emitted through the light exit hole;

[0015] The photodetector is used to detect scattered light within the integrating sphere.

[0016] Preferably, the testing system further includes a beam splitter and a second laser power meter.

[0017] The beam splitter is used to split the laser emitted by the laser into a first laser beam and a second laser beam; the second laser power meter is used to receive the second laser beam, and the laser beam incident through the entrance aperture is the first laser beam.

[0018] Preferably, the center wavelength of the laser output is in the intrinsic absorption band of the medium under test.

[0019] Preferably, at least one of the two reflectors is a concave reflector.

[0020] A second aspect of the present invention provides a high-precision method for testing the scattering and absorption loss coefficient of optical materials, the method comprising:

[0021] The incident laser power entering through the entrance aperture is obtained by the second laser power meter, and the stability of the laser is detected. The emitted laser power exiting through the exit aperture is obtained by the first laser power meter, and the total transmittance of the medium under test is calculated.

[0022] No medium to be measured is placed between the two mirrors, and the incident power is P. i A pulsed laser is incident on an integrating sphere, and the photodetector measures the intensity of the scattered pulse signal as D. i ;

[0023] The medium to be measured is placed between the two mirrors, and the incident power is P. i A pulsed laser is incident on an integrating sphere and the medium under test. The laser power P emitted after reflection from the medium under test is measured by a first laser power meter. s The photodetector measured the intensity of the scattered pulse signal at this time as D. s ;

[0024] According to D respectively s D i or P s P i Calculate the scattering rate of the medium under test;

[0025] The total loss coefficient of the test medium is calculated based on the total transmittance and scattering rate of the laser, the reflectivity of the incident surface of the test medium, the length of the test medium, and the number of times the laser passes through the test medium.

[0026] The scattering coefficient of the test medium is calculated based on the total transmittance and scattering rate of the laser, the reflectivity of the incident surface of the test medium, the length of the test medium, the number of times the laser passes through the test medium, and the total loss coefficient of the test medium.

[0027] The absorption coefficient of the medium under test is calculated based on the scattering coefficient and the total loss coefficient of the medium under test.

[0028] Furthermore, the calculation of the total transmittance of the medium under test includes:

[0029] According to Formula 1

[0030]

[0031] Calculate the total transmittance T of the medium under test. n , where P i P is the incident laser power. t This represents the output laser power.

[0032] Furthermore, the calculation of the scattering rate of the medium under test includes:

[0033] According to Formula 2

[0034]

[0035] Calculate the scattering rate S of the medium under test. n , where P s D represents the power of the laser emitted after reflection from the medium under test. s P represents the intensity of the scattered pulse signal scattered by the medium under test when the medium is placed inside the integrating sphere. i D is the power of the incident laser. i The intensity of the scattered pulse signal is when there is no medium to be measured inside the integrating sphere.

[0036] Furthermore, the method for calculating the total loss coefficient of the medium under test includes:

[0037] According to Formula 3

[0038]

[0039] Calculate the total loss coefficient 'a' of the medium under test, where T n R represents the total transmittance of the medium being measured. b R is the reflectivity of the incident surface of the medium under test. m Let L be the reflectivity of the two mirrors on both sides of the medium under test, L be the length of the medium under test, and n be the number of times the laser passes through the medium under test.

[0040] Furthermore, the method for calculating the scattering coefficient of the medium under test includes:

[0041] According to Formula 4

[0042]

[0043] Calculate the scattering coefficient α of the medium under test. s , of which S n R is the scattering rate of the medium under test; b R is the reflectivity of the incident surface of the medium under test. m Let L be the reflectivity of the two mirrors on both sides of the medium under test, L be the length of the medium under test, and n be the number of times the laser passes through the medium under test.

[0044] Furthermore, the method for calculating the absorption coefficient includes:

[0045] According to formula 5

[0046] a a =-a s

[0047] Among them, a a Let a be the absorption coefficient of the medium being measured. s denoted as scattering coefficient of the medium under test, and α as total loss coefficient of the medium under test.

[0048] The beneficial effects of this invention are as follows:

[0049] This invention sets reflectors on both sides of the medium under test, forming a self-reproducing enhancement cavity between the two reflectors. This controls the transmission and reflection of laser light between the two reflectors, enabling tunable multi-path laser transmission within the medium. This significantly increases the scattering and absorption losses of the medium under test, thereby achieving high-precision measurement of the scattering loss coefficient and absorption loss coefficient of extremely low optical loss optical materials. This provides a better characterization of the optical material's performance and offers important references for improving the preparation methods and parameters of the medium under test.

[0050] Meanwhile, by setting two mirrors with opposite surfaces inside the integrating sphere, this invention is independent of the medium under test. It can measure any optical material without modifying the medium under test. Since the current manufacturing process of mirrors is very mature, the quality of the mirrors produced is very high. Moreover, compared with other light reflection devices, mirrors generally have extremely high reflectivity. It can be seen that the test system of this invention is not affected by the manufacturing quality of the mirrors. The test system is more stable and the measured scattering loss coefficient and absorption loss coefficient data have extremely high accuracy. Attached Figure Description

[0051] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0052] Figure 1 This diagram illustrates a high-precision optical material scattering and absorption loss coefficient testing system provided by an embodiment of the present invention, where the two reflecting mirrors are a plane reflecting mirror and a concave reflecting mirror.

[0053] Figure 2 A schematic diagram of an integrating sphere structure provided in an embodiment of the present invention is shown.

[0054] Figure 3 This diagram illustrates a high-precision optical material scattering and absorption loss coefficient testing system provided by an embodiment of the present invention, in which both mirrors are planar mirrors.

[0055] Figure 4 This diagram shows a three-dimensional structure of the support rod, fixing mechanism, and synchronous rotation mechanism in an integrating sphere according to an embodiment of the present invention.

[0056] Figure 5 The diagram shows a high-precision optical material scattering and absorption loss coefficient testing system according to an embodiment of the present invention.

[0057] Figure 6 A schematic diagram of the structure of a computer system for implementing the apparatus provided in the embodiments of the present invention is shown. Detailed Implementation

[0058] To more clearly illustrate the present invention, the following description, in conjunction with embodiments and accompanying drawings, further explains the invention. Similar components in the drawings are indicated by the same reference numerals. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention.

[0059] The first aspect of this invention provides a high-precision optical material scattering and absorption loss coefficient testing system, such as... Figure 1 As shown, it includes a laser 1, a first laser power meter 5, an integrating sphere 2, a medium under test 4, and a photodetector 3;

[0060] The integrating sphere 2 is provided with two mirrors 10 facing each other;

[0061] like Figure 2 As shown, the integrating sphere 2 is provided with an entrance aperture 8, an exit aperture 9, and a detection aperture 11;

[0062] The positions of the light entrance aperture 8, the reflector 10 and the light exit aperture 9 are configured such that the laser light incident through the light entrance aperture 8 is reflected multiple times by the reflector 10 and then exits through the light exit aperture 9.

[0063] More specifically, the test medium 4 is a transparent optical material;

[0064] The first laser power meter 5 is used to receive the laser emitted through the light exit hole 9;

[0065] The photodetector 3 is used to detect the scattered light inside the integrating sphere 2.

[0066] In one possible implementation, the test system further includes a beam splitter 7 and a second laser power meter 6;

[0067] The beam splitter 7 is used to split the laser emitted by the laser 1 into a first laser beam and a second laser beam; the second laser power meter 6 is used to receive the second laser beam, and the laser beam incident through the entrance aperture 8 is the first laser beam.

[0068] In this invention, the second laser power meter 6 is used to detect the stability of the laser. When the second laser beam is detected to be unstable, the laser 1 is immediately adjusted or replaced to reduce the interference of laser instability on the data results and ensure the stability and objectivity of the test in this invention.

[0069] In one possible implementation, the laser 1 is one or a combination of a continuous laser output laser and a pulsed laser output laser.

[0070] In one possible implementation, the laser 1 outputs a center wavelength in the eigenabsorption band of the medium under test 4. When the laser is in the eigenabsorption band of the medium under test 4, it will affect the test results of the dielectric loss coefficient in this application. This implementation uses a laser in the eigenabsorption band to ensure the accuracy and objectivity of the system's test.

[0071] In one possible implementation, at least one of the two reflectors is a concave reflector.

[0072] In one possible implementation, preferably, the reflector is a high-reflectivity reflector, with a preferred reflectivity range of 96% to 99.9%.

[0073] Compared to planar mirrors, concave mirrors make it easier to control the laser beam path and calculate the number of reflections.

[0074] In one possible implementation, the system further includes an oscilloscope, which is communicatively connected to the photodetector 3. The oscilloscope transforms invisible electrical signals into visible images, facilitating the study of various electrical phenomena. The oscilloscope uses a narrow beam of high-speed electrons to strike a screen coated with a fluorescent material, producing tiny light spots (this is the working principle of a traditional analog oscilloscope). Under the influence of the measured signal, the electron beam acts like the tip of a pen, tracing the instantaneous value change curve of the measured signal on the screen. The oscilloscope allows observation of waveforms showing the amplitude changes of various signals over time, and it can also be used to test various electrical quantities, such as voltage, current, frequency, phase difference, modulation amplitude, etc.

[0075] In a specific example, such as Figure 4As shown, in the first method for adjusting the laser optical path, the testing system further includes a support rod 12, a fixing mechanism 13, and a synchronous rotation mechanism 14. The fixing mechanism is equipped with a clamp for fixing the medium to be tested. The two ends of the support rod 12 are fixedly connected to the fixing mechanism 13 and the integrating sphere 2, respectively. The synchronous rotation mechanism 14 is rotatably connected to the support rod 12, located between the fixing mechanism 13 and the integrating sphere 2. The synchronous rotation mechanism 14 is rotatably connected to the bottom of the reflector 10. The rotation axis of the reflector 10 is parallel to the rotation axis of the synchronous rotation mechanism 14. The outer walls of the support rod 12, the fixing mechanism 13, and the synchronous rotation mechanism 14 are coated with the same white diffuse reflective material as the inner wall of the integrating sphere 2. With the laser angle incident through the entrance aperture remaining constant, the rotation angle of the synchronous rotation mechanism 14 is adjusted to allow the laser to be incident on a suitable position on the reflector. The rotation angle of the reflector 10 itself is then adjusted to adjust the angle between the laser and the reflector, thereby adjusting the optical path. It should be noted that all rotating connections in this invention are damped rotating connections, meaning they rotate when subjected to force and do not rotate when not subjected to force.

[0076] In the second method of adjusting the optical path, after fixing the position and angle of the reflector 10 and the medium under test 4, the optical path is controlled by adjusting the angle of the laser incident through the entrance hole 8. The first method of adjusting the optical path is preferred in this invention. Compared to the second method, the first method allows for more flexible adjustment of the optical path, and the resulting optical path is denser, better meeting the testing requirements.

[0077] like Figure 5 As shown, the second invention provides a high-precision method for testing the scattering and absorption loss coefficient of optical materials.

[0078] Step S1: Obtain the incident laser power through the second laser power meter 6 and detect the stability of the laser 1; obtain the emitted laser power from the exit hole 9 through the first laser power meter 5 and calculate the total transmittance of the medium 4 under test.

[0079] Step S2: Do not place the medium to be measured 4 between the two reflecting mirrors 10, and use an incident power of P. i The pulsed laser is incident on integrating sphere 2, and the photodetector 3 measures the intensity of the scattered pulse signal as D. i ;

[0080] Step S3: Place the medium to be tested 4 between the two reflecting mirrors 10, and use an incident power of P. i The pulsed laser is incident on the integrating sphere 2 and the test medium 4, and the laser power P emitted after reflection from the test medium 4 is measured by the first laser power meter 5. s The photodetector 3 measured the intensity of the scattered pulse signal at this time as D. s ;

[0081] Step S4: According to D respectively s D i or P s P i Calculate the scattering rate of the medium 4 under test;

[0082] Step S5: Calculate the total loss coefficient of the test medium 4 based on the total transmittance and scattering rate of the laser, the reflectivity of the incident surface of the test medium 4, the length of the test medium 4, and the number of times the laser passes through the test medium 4.

[0083] Step S6: Calculate the scattering coefficient of the test medium 4 based on the total transmittance of the laser, the scattering rate, the reflectivity of the incident surface of the test medium 4, the length of the test medium 4, the number of times the laser passes through the test medium 4, and the total loss coefficient of the test medium 4.

[0084] Step S7: Calculate the absorption coefficient of the medium 4 under test based on the scattering coefficient and the total loss coefficient of the medium 4 under test.

[0085] In one possible implementation, calculating the total transmittance of the test medium 4 includes:

[0086] According to Formula 1

[0087]

[0088] Calculate the total transmittance T of the test medium 4 n , where P i P is the incident laser power. t This represents the output laser power.

[0089] In one possible implementation, calculating the scattering rate of the test medium 4 includes:

[0090] According to Formula 2

[0091]

[0092] Calculate the scattering rate S of the medium under test 4. n , where P s D represents the power of the laser emitted after reflection from the test medium 4. s P represents the intensity of the scattered pulse signal scattered by the medium 4 when the medium 4 to be measured is placed inside the integrating sphere 2; i D is the power of the incident laser. i The intensity of the scattered pulse signal is when there is no medium 4 to be measured inside the integrating sphere 2.

[0093] In one possible implementation, the method for calculating the total loss coefficient of the medium under test 4 includes:

[0094] According to Formula 3

[0095]

[0096] Calculate the total loss coefficient 'a' of the medium under test 4, where T n R represents the total transmittance of the test medium 4. b R is the reflectivity of the incident surface of the medium 4 under test. m Let L be the reflectivity of the two mirrors 10 on both sides of the medium under test 4, L be the length of the medium under test 4, and n be the number of times the laser is reflected on the mirror 10.

[0097] In one possible implementation, the method for calculating the scattering coefficient of the test medium 4 includes:

[0098] According to Formula 4

[0099]

[0100] Calculate the scattering coefficient a of the medium under test 4. s , of which S n R represents the scattering rate of the medium 4 under test. b R is the reflectivity of the incident surface of the medium 4 under test. m Let L be the reflectivity of the two mirrors 10 on both sides of the medium under test 4, L be the length of the medium under test 4, and n be the number of times the laser is reflected on the mirror 10.

[0101] In one possible implementation, the absorption coefficient is calculated by:

[0102] According to formula 5

[0103] a a =aa s

[0104] Among them, a a Let a be the absorption coefficient of the medium 4 to be tested. s denoted as scattering coefficient of medium 4 under test, and α is the total loss coefficient of medium 4 under test.

[0105] Those skilled in the art should understand that although the above steps are described in the order of steps S1 to S6, it does not mean that they must be executed in this order. For example, step S3 can be executed first, followed by step S5, as long as it does not violate the logic.

[0106] In one specific embodiment, this embodiment provides a testing device for accurately measuring the absorption and scattering coefficients of Nd:YAG ceramic laser working material.

[0107] For a detailed structural reference in this embodiment... Figure 1This embodiment provides a testing system for accurately measuring the absorption and scattering coefficients of Nd:YAG ceramic laser working materials.

[0108] Example 1

[0109] This embodiment provides a testing system for accurately measuring the absorption and scattering coefficients of Nd:YAG ceramic laser working materials.

[0110] For a detailed structural reference in this embodiment... Figure 1 The Nd:YAG ceramic material to be tested (test medium 4) is placed and fixed between the two reflectors 10, wherein reflector M1 is a plane reflector and reflector M2 is a concave reflector. The space between reflector M1 and reflector M2 forms a self-reproducing enhancement cavity (MPC cavity). The test laser enters the integrating sphere 2 through the entrance aperture 8 and enters from the left interface of the ceramic sample. After passing through the test medium 4, it exits from the right interface and strikes the reflector 10 (M2). After being reflected by the surface of the reflector 10 (M2), the laser passes through the test medium 4 again and is reflected back to the reflector (M1). The laser reflects back and forth between the two reflectors 10 (M1 and M2) and completes multi-path transmission before finally exiting from the exit aperture 9 on the integrating sphere 2.

[0111] Incident laser power P i After reflection from the incident end face of the test medium 4, scattering and absorption within the test medium 4, the laser beam is transmitted through the output end face. The incident laser power P is measured by the second laser power meter 6 and the first laser power meter 5, respectively. i and emitted laser power P t The total transmittance of the test medium 4 to the incident laser is obtained. During this measurement process, laser 1 provides continuous laser output. When the test medium 4 is not placed, the light output aperture 9 is closed, making the power P. i The pulsed laser incident on the integrating sphere is detected by the photodetector 3 placed in the detection aperture 11 and transmitted to a high-precision oscilloscope for processing, yielding a pulse signal intensity of D. i Place the sample in, open the light output aperture 9, and allow the pulsed laser P to enter. i After the incident sample undergoes multiple transmissions and exits, the power measured by photodetector 3 is P. s The intensity of the scattered pulse signal at time D s The total scattering rate of the sample was obtained during this measurement process, using a pulsed laser output. The transmittance T was then used. n With scattering rate S n The total loss coefficient, absorption coefficient, and scattering coefficient of the ceramic sample can be obtained by measuring the values ​​and using precise calculation formulas for the sample's total loss coefficient, scattering coefficient, and absorption coefficient.

[0112] In this embodiment, laser 1 is an acousto-optic Q-switched pulsed laser with an output center wavelength of 1064nm. When the Q-switch is in the off state, it outputs continuous laser with an instability of less than 0.5%. When the Q-switch is in the on state, it outputs pulsed laser with a repetition frequency of 10Hz and a pulse width of approximately 200ns.

[0113] In this embodiment, the integrating sphere size is the outer diameter. inner diameter The diameters of the entrance aperture, exit aperture, and detector aperture are respectively and

[0114] The measurement result in this embodiment is that the scattering coefficient of the tested medium, 4Nd:YAG ceramic material, is 0.001 cm⁻¹. -1 Absorption coefficient 0.001cm -1 The total loss coefficient is 0.002cm. -1 The scattering loss of the test medium 4 is relatively low compared with the absorption loss caused by extrinsic absorption, and its optical performance is good.

[0115] The experimental setup provided in this embodiment for accurately measuring the scattering and absorption coefficients of Nd:YAG ceramic laser working media has the following advantages over other loss measurement methods: it utilizes highly stable continuous lasers and high peak power pulsed lasers to test the transmittance T of the sample, respectively. n With scattering rate S n It achieves high measurement accuracy; a self-reproducible enhanced cavity combined with an integrating sphere diffuse reflection structure is specially designed to enable multi-path transmission of laser in laser materials, thereby increasing the absorption and scattering loss of ceramic samples by an order of magnitude. This enables high-precision measurement of the absorption and scattering of laser materials with extremely low optical loss, and can better characterize the optical properties of laser working media.

[0116] This embodiment provides another accurate measurement device for the absorption and scattering loss coefficient of Nd:YAG ceramic laser working material (test medium 4), such as... Figure 3 As shown, this embodiment is similar to Embodiment 1, except that:

[0117] The concave reflector is replaced with a plane reflector. The Nd:YAG ceramic material to be tested (test medium 4) is placed and fixed between the two reflectors 10 (M1, M2). The test laser enters the integrating sphere 2 through the entrance aperture 8 and is incident at a certain angle from the left interface of the ceramic sample. After passing through the test medium, it exits from the right interface and strikes the reflector M2. After being reflected by the reflector M2, it is reflected again through the test medium 4 and onto the reflector M1. The laser is reflected back and forth between the two reflectors, and after completing multiple transmissions, it finally exits from the exit aperture 9 on the integrating sphere.

[0118] More specifically, in a preferred embodiment of the present invention, at least one of the two reflectors 10 is a concave reflector, and the incident light resonates with the cavity and the mode is matched, thereby forming an in-situ enhancement cavity between the two reflectors.

[0119] like Figure 6 As shown, a computer system suitable for implementing a high-precision optical material scattering and absorption loss coefficient testing method provided in the above embodiments includes a central processing module (CPU), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) or a program loaded from a storage portion into a random access memory (RAM). The RAM also stores various programs and data required for the operation of the computer system. The CPU, ROM, and RAM are interconnected via a bus. An input / output (I / O) interface is also connected to the bus.

[0120] The following components are connected to the I / O interface: input sections including keyboards, mice, etc.; output sections including liquid crystal displays (LCDs) and speakers, etc.; storage sections including hard disks, etc.; and communication sections including network interface cards such as LAN cards and modems. The communication sections perform communication processing via networks such as the Internet. Drives are also connected to the I / O interface as needed. Removable media, such as disks, optical disks, magneto-optical disks, semiconductor memories, etc., are installed on the drive as needed so that computer programs read from them can be installed into the storage section as required.

[0121] Specifically, according to this embodiment, the process described in the flowchart above can be implemented as a computer software program. For example, this embodiment includes a computer program product comprising a computer program tangibly embodied on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via a communication component, and / or installed from a removable medium.

[0122] The flowcharts and schematic diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of the system, method, and computer program product of this embodiment. In this regard, each block in the flowchart or schematic diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the schematic diagram and / or flowchart, and combinations of blocks in the schematic diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0123] This embodiment also provides a non-volatile computer storage medium. This non-volatile computer storage medium can be the non-volatile computer storage medium included in the above-described device, or it can be a separate non-volatile computer storage medium not assembled into the terminal. The non-volatile computer storage medium stores one or more programs. When one or more programs are executed by a device, the device performs the following steps: Step S1: Obtain the incident laser power through the second laser power meter 6 and detect the stability of the laser 1; obtain the emitted laser power from the exit aperture 9 through the first laser power meter 5 and calculate the total transmittance of the test medium 4; Step S2: Do not place the test medium 4 between the two reflectors 10, and use an incident power of P... i The pulsed laser is incident on integrating sphere 2, and the photodetector 3 measures the intensity of the scattered pulse signal as D. i Step S3: Place the medium to be tested 4 between the two reflecting mirrors 10, and use an incident power of P. i The pulsed laser is incident on the integrating sphere 2 and the test medium 4, and the laser power P emitted after reflection from the test medium 4 is measured by the first laser power meter 5. s The photodetector 3 measured the intensity of the scattered pulse signal at this time as D. s Step S4: According to D respectively s D i or P s P iCalculate the scattering rate of the test medium 4; Step S5: Calculate the total loss coefficient of the test medium 4 based on the total transmittance of the laser, the scattering rate, the reflectivity of the incident surface of the test medium 4, the length of the test medium 4, and the number of times the laser passes through the test medium 4; Step S6: Calculate the scattering coefficient of the test medium 4 based on the total transmittance of the laser, the scattering rate, the reflectivity of the incident surface of the test medium 4, the length of the test medium 4, the number of times the laser passes through the test medium 4, and the total loss coefficient of the test medium 4; Step S7: Calculate the absorption coefficient of the test medium 4 based on the scattering coefficient and the total loss coefficient of the test medium 4.

[0124] This invention sets reflectors on both sides of the test medium to control the transmission and reflection of laser within the medium; it designs a self-reproducing enhancement cavity combined with an integrating sphere diffuse reflection structure to achieve tunable multi-path laser transmission within the medium, thereby increasing the scattering and absorption losses of the test medium by an order of magnitude. This enables high-precision measurement of the scattering loss coefficient and absorption loss coefficient of extremely low optical loss optical materials, better characterizing the performance of optical materials, and providing important reference for the improvement of test medium preparation methods and parameters.

[0125] Meanwhile, by setting two mirrors with opposite surfaces inside the integrating sphere, this invention eliminates the need to modify the medium under test. Since the current mirror manufacturing process is very mature, the quality of the mirrors produced is very high. Moreover, compared with other light reflection devices, mirrors generally have extremely high reflectivity. It can be seen that the test system of this invention is not affected by the quality of the mirror manufacturing process, the test system is more stable, and the measured data of scattering loss coefficient and absorption loss coefficient have extremely high accuracy.

[0126] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0127] It should also be noted that in the description of this invention, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0128] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A high-precision optical material scattering and absorption loss coefficient testing system, characterized in that, The testing system includes a laser, a first laser power meter, an integrating sphere, a medium under test, and a photodetector. The integrating sphere contains two mirrors with their mirror surfaces facing each other; the medium to be measured can be placed between the two mirrors. The integrating sphere is provided with an entrance aperture, an exit aperture, and a detection aperture; The positions of the light entrance aperture, the reflector, and the light exit aperture are configured such that the laser light entering through the light entrance aperture is reflected multiple times by the reflector and then exits through the light exit aperture. The first laser power meter is used to receive the laser emitted through the light exit hole; The photodetector is used to detect scattered light within the integrating sphere; At least one of the two reflectors is a concave reflector to form a self-enhancing cavity between the two reflectors; The incident light entering from the entrance aperture is configured to resonate with and mode-match the self-presentation enhancement cavity; The testing system is used to perform high-precision testing methods for the scattering and absorption loss coefficients of optical materials, including: The incident laser power entering through the entrance aperture is obtained by the second laser power meter, and the stability of the laser is detected. The emitted laser power exiting through the exit aperture is obtained by the first laser power meter, and the total transmittance of the medium under test is calculated. No medium to be measured is placed between the two mirrors, and the incident power is P. i A pulsed laser is incident on an integrating sphere, and the photodetector measures the intensity of the scattered pulse signal as D. i ; The medium to be measured is placed between the two mirrors, and the incident power is P. i A pulsed laser is incident on an integrating sphere and the medium under test. The laser power P emitted after reflection from the medium under test is measured by a first laser power meter. s The photodetector measured the intensity of the scattered pulse signal at this time as D. s ; According to D respectively s D i or P s P i Calculate the scattering rate of the medium under test; The total loss coefficient of the test medium is calculated based on the total transmittance and scattering rate of the laser, the reflectivity of the incident surface of the test medium, the length of the test medium, and the number of times the laser passes through the test medium. The scattering coefficient of the test medium is calculated based on the total transmittance and scattering rate of the laser, the reflectivity of the incident surface of the test medium, the length of the test medium, the number of times the laser passes through the test medium, and the total loss coefficient of the test medium. The absorption coefficient of the medium under test is calculated based on the scattering coefficient and the total loss coefficient of the medium under test.

2. The system according to claim 1, characterized in that, The testing system also includes a beam splitter and a second laser power meter; The beam splitter is used to split the laser emitted by the laser into a first laser beam and a second laser beam; the second laser power meter is used to receive the second laser beam, and the laser beam incident through the entrance aperture is the first laser beam.

3. The system according to claim 1, characterized in that, The laser output center wavelength is in the intrinsic absorption band of the medium under test.

4. The system according to claim 1, characterized in that, The calculation of the total transmittance of the medium under test includes: According to Formula 1 Calculate the total transmittance Tn of the medium under test, where Pi is the incident laser power and Pt is the output laser power.

5. The system according to claim 1, characterized in that, The calculation of the scattering rate of the medium under test includes: According to Formula 2 Calculate the scattering rate S of the medium under test. n , where P s D represents the power of the laser emitted after reflection from the medium under test. s P represents the intensity of the scattered pulse signal scattered by the medium under test when the medium is placed inside the integrating sphere. i D is the power of the incident laser. i The intensity of the scattered pulse signal is when there is no medium to be measured inside the integrating sphere.

6. The system according to claim 1, characterized in that, The method for calculating the total loss coefficient of the medium under test includes: According to Formula 3 Calculate the total loss coefficient of the medium under test. , among which, T n The total transmittance of the medium being measured; The reflectivity of the incident surface of the medium under test is denoted as . The reflectivity of the mirrors on both sides of the medium under test is denoted as . denoted as , where is the length of the medium to be tested, and n is the number of times the laser passes through the medium.

7. The system according to claim 1, characterized in that, The method for calculating the scattering coefficient of the medium under test includes: According to Formula 4 Calculate the scattering coefficient of the medium under test , of which S n The scattering rate of the medium under test; The reflectivity of the incident surface of the medium under test is denoted as . The reflectivity of the mirrors on both sides of the medium under test is denoted as . Let be the length of the medium to be measured, and n be the number of times the laser passes through the medium. The total loss coefficient of the medium under test.

8. The system according to claim 1, characterized in that, The method for calculating the absorption coefficient includes: According to formula 5 in, Let be the absorption coefficient of the medium under test. The scattering coefficient of the medium under test is denoted as . The total loss coefficient of the medium under test.

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