Testing device and method based on SiPM photon detection efficiency

Abstract

The invention discloses a SiPM photon detection efficiency-based test device and method, and the method comprises the steps: S1, applying a reverse bias voltage in an allowable range to SiPM; s2, acquiring an output signal of the SiPM under a light condition; s3, acquiring an output signal of the SiPM in the dark environment; s4, acquiring an output signal of the SiPM after the proper pulse light source is applied; and S5, calculating the photon detection efficiency PDE according to the reading of the optical power meter, the n1 and the n2 under the pulsed light condition. According to the SiPM photon detection efficiency-based test device and method disclosed by the invention, the interference of related noise is eliminated by calculating the ratio of the non-photon pulse to the total pulse, the more accurate photon detection efficiency of SiPM under different working conditions can be obtained, and the characterization and application of SiPM are more reliable.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic testing, and in particular relates to a testing device based on SiPM photon detection efficiency and a testing method based on SiPM photon detection efficiency. Background Art

[0002] Silicon photomultiplier (SiPM) is a new type of optoelectronic detection device. It is a solid-state photodetector composed of hundreds or thousands of integrated single-photon avalanche diode (SPAD) arrays connected in parallel. SiPM has good photon counting capability and single-photon sensitivity. The avalanche process of the internal SPAD pixel is very rapid, and the arrival time of the detection photon can be obtained within tens of picoseconds. The advantages of high sensitivity, large dynamic range, good time resolution and little interference from magnetic fields make SiPM have a wide range of application scenarios in low light intensity and fast timing detection conditions. It has been applied to detection and ranging (LIDAR), functional spectroscopy, fluorescence detection, quantum physics and quantum informatics.

[0003] Photon detection efficiency (PDE) is one of the important performance indicators of SiPM, which reflects the probability of generating a detectable electrical pulse after a photon incident on SiPM. Where n is the number of photons incident on the device, n pe The number of photons detected by SiPM. The photon detection efficiency of SiPM will change with the device bias and the wavelength of the incident light. Therefore, accurate measurement of the photon detection efficiency of SiPM is very important for characterizing SiPM performance and weak light precision detection applications.

[0004] Due to the weak light detection properties of SiPM and the characteristics of dark count, optical crosstalk and after-pulse, the traditional SiPM photon detection efficiency test method has two problems:

[0005] First, the light intensity irradiating the SiPM under the test conditions is too weak, making it difficult to accurately calibrate and measure it;

[0006] Second, due to the influence of optical crosstalk and after-pulses, the measured electrical pulse distribution is often distorted, which makes the calculated photon detection efficiency too large. These problems will affect the test of SiPM's photon detection efficiency and reduce the accuracy in SiPM application scenarios.

[0007] Therefore, further improvements are made to the above problems. Summary of the invention

[0008] The main purpose of the present invention is to provide a testing device and method based on SiPM photon detection efficiency. By calculating the ratio of non-photon pulses to total pulses, the interference of correlated noise (optical crosstalk and after-pulses) is eliminated, and a more accurate photon detection efficiency of SiPM under different working conditions can be obtained, making the characterization and application of SiPM more reliable.

[0009] To achieve the above object, the present invention provides a method for testing the photon detection efficiency based on SiPM, comprising the following steps:

[0010] Step S1: applying a reverse bias voltage within an allowable range to the SiPM;

[0011] Step S2: Obtain the output signal of SiPM under light conditions, and determine the basic pulse peak value p0 of SiPM and the appropriate measurement light intensity;

[0012] Step S3: obtaining the output signal of the SiPM in a dark environment, and obtaining the ratio n1 of the number of basic pulse peak events to the total number of events in the dark environment;

[0013] Step S4: obtaining the output signal of the SiPM after applying a suitable pulse light source, and obtaining the ratio n2 of the number of basic pulse peak events to the total number of events under the pulse light environment;

[0014] Step S5: Calculate the photon detection efficiency PDE according to the optical power meter reading under the pulse light condition and n1 and n2.

[0015] As a further preferred technical solution of the above technical solution, step S3 is specifically implemented as the following steps:

[0016] Step S3.1: Count the SiPM output pulses in a dark environment, filter out the pulses with peak values ​​lower than a preset value, count the amplitudes of the remaining pulses, and draw a dark environment pulse amplitude distribution histogram;

[0017] Step S3.2: In the dark environment pulse amplitude distribution histogram, a Gaussian function is fitted to the distribution envelope of the basic pulse peak, and the number of dark environment basic pulse peak events is obtained by integrating within a preset interval, and the number is divided by the total number of events to obtain the ratio n1.

[0018] As a further preferred technical solution of the above technical solution, step S4 is specifically implemented as the following steps:

[0019] Step S4.1: Apply a pulse light source of appropriate intensity and record the light intensity at this time as P opt ;

[0020] Step S4.2, counting the SiPM output pulses in the pulse light environment, and drawing a pulse amplitude distribution histogram of the pulse light environment;

[0021] Step S4.3: In the pulse amplitude distribution histogram of the pulse light environment, fit the distribution envelope of the basic pulse peak with a Gaussian function, integrate it within a preset interval to obtain the number of basic pulse peak events in the pulse light environment, and divide it by the total number of events to obtain the ratio n2.

[0022] As a further preferred technical solution of the above technical solution, for step S5:

[0023] Photon detection efficiency T is the period of the pulse light source, and h·ν is the single photon energy of the light source.

[0024] In order to achieve the above objectives, the present invention also provides a testing device based on SiPM photon detection efficiency, comprising:

[0025] A light source assembly, used to generate a test light source and irradiate the test light source to the photosensitive surface of the SiPM;

[0026] An optical power measurement component, used to measure the intensity of the optical power irradiated onto the photosensitive surface of the SiPM;

[0027] Oscilloscope, used to receive the signal from SiPM and transmit it to the host computer;

[0028] The host computer is used to control the light source component to generate appropriate light, receive oscilloscope signals, and resolve pulses.

[0029] As a further preferred technical solution of the above technical solution, the light source assembly includes a single-wavelength pulse light source, an optical fiber and an integrating sphere, and the single-wavelength pulse light source is connected to the integrating sphere via the optical fiber.

[0030] As a further preferred technical solution of the above technical solution, the optical power measurement component includes an optical power meter and a pinhole. The pinhole should be close to the photosensitive surface of the SiPM and have a diameter smaller than the single pixel size of the SiPM.

[0031] As a further preferred technical solution of the above technical solution, before the formal test, the optical power of the optical power meter at the interface of the integrating sphere and behind the pinhole is recorded under a preset light source, so as to obtain the ratio R0 of the optical power at the integrating sphere interface to the optical power behind the pinhole. Then, the optical power meter is installed on the integrating sphere interface, and the light intensity irradiated on the photosensitive surface of the SiPM is the optical power meter reading P read / R0,P read It is the light intensity read by the optical power meter at the integrating sphere interface.

[0032] The beneficial effects of the present invention are:

[0033] By testing the ratio of the number of basic pulse peak events to the total number of events in a dark environment and a pulsed light environment, the influence of optical crosstalk and after-pulses during testing in a pulsed light environment is avoided, making the tested photon detection efficiency more accurate; the present invention attenuates the light irradiated onto the SiPM through a pinhole, and indirectly calculates the light intensity irradiated onto the SiPM through the ratio of the optical power meter behind the pinhole and the integrating sphere interface, thereby reducing the sensitivity requirements of the optical power meter. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic flow chart of the testing method of the present invention.

[0035] Figure 2 It is the dark environment pulse amplitude distribution histogram of the present invention.

[0036] Figure 3 It is a pulse amplitude distribution histogram of the pulse light environment of the present invention.

[0037] Figure 4 It is a schematic diagram of the structure of the testing device of the present invention.

[0038] The reference numerals include: 10, light source assembly; 11, pulse light source; 12, optical fiber; 13, integrating sphere; 20, optical power measurement assembly; 21, optical power meter; 22, pinhole; 30, SiPM; 40, oscilloscope; 50, host computer. DETAILED DESCRIPTION

[0039] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0040] In the preferred embodiments of the present invention, those skilled in the art should note that the SiPM and the like involved in the present invention may be regarded as prior art.

[0041] Preferred embodiments.

[0042] The present invention discloses a testing method based on SiPM photon detection efficiency, comprising the following steps:

[0043] Step S1: Apply a reverse bias voltage within the allowable range (in the chip manual) to the SiPM;

[0044] Step S2: Obtain the output signal of SiPM under light conditions, and determine the basic pulse peak value p0 of SiPM and the appropriate measurement light intensity;

[0045] Step S3: obtaining the output signal of the SiPM in a dark environment, and obtaining the ratio n1 of the number of basic pulse peak events to the total number of events in the dark environment;

[0046] Step S4: obtaining the output signal of the SiPM after applying a suitable pulse light source, and obtaining the ratio n2 of the number of basic pulse peak events to the total number of events under the pulse light environment;

[0047] Step S5: Calculate the photon detection efficiency PDE according to the optical power meter reading under the pulse light condition and n1 and n2.

[0048] Specifically, step S3 is implemented as follows:

[0049] Step S3.1: Count the SiPM output pulses in a dark environment, filter out the pulses with peak values ​​lower than a preset value (0.7p0), count the amplitudes of the remaining pulses, and draw (e.g. Figure 2 (shown) dark environment pulse amplitude distribution histogram;

[0050] Step S3.2: In the dark environment pulse amplitude distribution histogram, fit the distribution envelope of the basic pulse peak with a Gaussian function, integrate within a preset interval (±3σ) to obtain the number of dark environment basic pulse peak events, and divide it by the total number of events to obtain the ratio n1.

[0051] More specifically, step S4 is implemented as follows:

[0052] Step S4.1: Apply a pulse light source of appropriate intensity and record the light intensity at this time as P opt ;

[0053] Step S4.2, counting the SiPM output pulses in the pulse light environment and drawing (such as Figure 3 (shown) pulse amplitude distribution histogram of pulse light environment;

[0054] Step S4.3: In the pulse amplitude distribution histogram of the pulse light environment, fit a Gaussian function to the distribution envelope of the basic pulse peak, integrate it within the preset interval (±3σ) to obtain the number of basic pulse peak events in the pulse light environment, and divide it by the total number of events to obtain the ratio n2.

[0055] Furthermore, for step S5:

[0056] Photon detection efficiency T is the period of the pulse light source, and h·v is the single photon energy of the light source.

[0057] Preferably, in step S2, the appropriate measured light intensity refers to the measured average pulse peak value being 2 to 3 times the basic pulse peak value p0.

[0058] Preferably, in step S4, the pulse width of the pulse light source should be less than 10 ns, and the repetition rate should be lower than 10 MHz.

[0059] The present invention also discloses a testing device based on SiPM photon detection efficiency, comprising:

[0060] The light source assembly 10 is used to generate a test light source and irradiate the test light source to the photosensitive surface of the SiPM 30;

[0061] The optical power measuring component 20 is used to measure the optical power intensity irradiated onto the photosensitive surface of the SiPM 30;

[0062] Oscilloscope 40, used to receive the signal of SiPM 30 and transmit it to host computer 50;

[0063] The host computer 50 is used to control the light source assembly 10 to generate appropriate light, receive the signal from the oscilloscope 40, and perform pulse resolution processing.

[0064] Specifically, the light source assembly 10 includes a single-wavelength pulse light source 11 , an optical fiber 12 , and an integrating sphere 13 , and the single-wavelength pulse light source 11 is connected to the integrating sphere 13 via the optical fiber 12 .

[0065] More specifically, the optical power measurement component 20 includes an optical power meter 21 and a pinhole 22 . The pinhole 21 should be close to the photosensitive surface of the SiPM 30 and have a diameter (slightly) smaller than the single pixel size of the SiPM 30 .

[0066] Furthermore, the method for using the optical power measurement component is to record the optical power of the optical power meter 21 at the interface of the integrating sphere 13 and behind the pinhole 22 under a (stronger) preset light source before the formal test, so as to obtain the ratio R0 of the optical power at the integrating sphere interface to the optical power behind the pinhole. Then, the optical power meter is installed on the integrating sphere interface. During the test, the light intensity irradiated on the photosensitive surface of SiPM30 is the optical power meter reading P read / R0, where P read It is the light intensity read by the optical power meter at the integrating sphere interface.

[0067] Preferably, the bandwidth of the oscilloscope 40 should be greater than 4 GHz.

[0068] The host computer 50 is any computer capable of running LABVIEW.

[0069] It is worth mentioning that the technical features such as SiPM involved in the patent application of the present invention should be regarded as the prior art. The specific structure, working principle and possible control method and spatial layout method of these technical features can be selected by conventional methods in the field, and should not be regarded as the inventive point of the patent of the present invention. The patent of the present invention will not be further elaborated.

[0070] For those skilled in the art, it is still possible to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A test method based on SiPM photon detection efficiency, characterized in that: The following steps are involved: Step S1: applying a reverse bias voltage within an allowable range to the SiPM; Step S2: Obtain the output signal of SiPM under light conditions, and determine the basic pulse peak value p0 of SiPM and the appropriate measurement light intensity; Step S3: obtaining the output signal of the SiPM in a dark environment, and obtaining the ratio n1 of the number of basic pulse peak events to the total number of events in the dark environment; Step S4: obtaining the output signal of the SiPM after applying a suitable pulse light source, and obtaining the ratio n2 of the number of basic pulse peak events to the total number of events under the pulse light environment; Step S5: Calculate the photon detection efficiency PDE according to the optical power meter reading under the pulse light condition and n1 and n2.

2. A method for testing SiPM photon detection efficiency according to claim 1, characterized in that: Step S3 is specifically implemented as the following steps: Step S3.1: Count the SiPM output pulses in a dark environment, filter out the pulses with peak values ​​lower than a preset value, count the amplitudes of the remaining pulses, and draw a dark environment pulse amplitude distribution histogram; Step S3.2: In the dark environment pulse amplitude distribution histogram, a Gaussian function is fitted to the distribution envelope of the basic pulse peak, and the number of dark environment basic pulse peak events is obtained by integrating within a preset interval, and the number is divided by the total number of events to obtain the ratio n1.

3. A method for testing SiPM photon detection efficiency according to claim 2, characterized in that: Step S4 is specifically implemented as follows: Step S4.1: Apply a pulse light source of appropriate intensity and record the light intensity at this time as P opt ; Step S4.2, counting the SiPM output pulses in the pulse light environment, and drawing a pulse amplitude distribution histogram of the pulse light environment; Step S4.3: In the pulse amplitude distribution histogram of the pulse light environment, fit the distribution envelope of the basic pulse peak with a Gaussian function, integrate within a preset interval to obtain the number of basic pulse peak events in the pulse light environment, and divide it by the total number of events to obtain the ratio n2.

4. A method for testing SiPM photon detection efficiency according to claim 3, characterized in that: For step S5: Photon detection efficiency T is the period of the pulse light source, and h·ν is the single photon energy of the light source.

5. A testing device based on SiPM photon detection efficiency, applied to a testing method based on SiPM photon detection efficiency according to any one of claims 1 to 4, characterized in that: include: A light source assembly, used to generate a test light source and irradiate the test light source to the photosensitive surface of the SiPM; An optical power measurement component, used to measure the intensity of the optical power irradiated onto the photosensitive surface of the SiPM; Oscilloscope, used to receive the signal from SiPM and transmit it to the host computer; The host computer is used to control the light source component to generate appropriate light, receive oscilloscope signals, and resolve pulses.

6. A testing device based on SiPM photon detection efficiency according to claim 5, characterized in that: The light source assembly comprises a single-wavelength pulse light source, an optical fiber and an integrating sphere, and the single-wavelength pulse light source is connected to the integrating sphere via the optical fiber.

7. A testing device based on SiPM photon detection efficiency according to claim 6, characterized in that: The optical power measurement component includes an optical power meter and a pinhole. The pinhole should be close to the photosensitive surface of the SiPM and have a diameter smaller than the single pixel size of the SiPM.

8. The testing device based on SiPM photon detection efficiency according to claim 7, characterized in that: Before the formal test, the optical power meter should be recorded under the preset light source at the interface of the integrating sphere and behind the pinhole to obtain the ratio R0 of the optical power at the integrating sphere interface to the optical power behind the pinhole. Then the optical power meter is installed on the integrating sphere interface, and the light intensity irradiated on the photosensitive surface of the SiPM is the optical power meter reading P. read / R0,P read It is the light intensity read by the optical power meter at the integrating sphere interface.

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