Gated double-optical-path nanosecond transient circular polarization emission spectrometer

Abstract

The invention belongs to the field of spectral measurement, in particular to the field of new material detection. The invention provides a gated double-light-path nanosecond transient circular polarization emission spectrometer, which comprises an excitation device, a light source device, a light source device, a light source device, a light source device, a control device and a light source device, and is characterized in that the excitation device is used for exciting a sample to emit light; the beam splitting device is used for equally splitting the parallel light into two light-emitting light beams which are respectively used for left-hand / right-hand circularly polarized light measurement; the levorotatory / dextrorotatory circularly polarized light collecting device is used for selecting levorotatory / dextrorotatory circularly polarized light in the equally divided light-emitting beams and converging the levorotatory / dextrorotatory circularly polarized light; the levorotatory / dextrorotatory circularly polarized light detection device is used for carrying out monochromatic processing on light with required wavelength in a levorotatory / dextrorotatory circularly polarized light spectrum and then carrying out photoelectric detection; the dual-channel gate delay integration device is used for respectively acquiring signals of the left-handed / right-handed circularly polarized light detection device; and the computer is used for carrying out analysis, graphic display and storage on the signals acquired by the dual-channel gate delay integration device.

Description

Technical Field

[0001] The present invention belongs to the field of spectral measurement, in particular to the field of new material detection, relates to a gated measurement technology, and in particular to a gated dual-light path nanosecond transient circularly polarized emission spectrometer. Background Art

[0002] With the development of optoelectronic materials, biomolecular dynamics and quantum information technology, the demand for studying the dynamic processes of excited states of matter is becoming increasingly urgent. As a key tool for revealing the dynamic behavior of molecules / materials at the femtosecond to millisecond scale, the technological innovation of transient spectroscopy technology directly affects breakthroughs in basic scientific research and industrial applications. In recent years, the breakthrough application of chiral materials in organic light-emitting diodes (OLEDs), spintronic devices and biosensors has made advanced spectroscopy technology with both time resolution and circular polarization detection capabilities an international research hotspot. However, the inherent contradictions of the existing technology system in terms of time resolution, polarization fidelity and system stability have become the core bottleneck restricting the study of chiral ultrafast dynamics.

[0003] In the field of nanosecond transient luminescence measurement, the mainstream measurement techniques are time-correlated single photon counting (TCSPC) and multi-channel scanning (MCS). The former has important applications in the sub-nanosecond to sub-microsecond range, while the latter is widely used in the nanosecond to microsecond range. In transient circularly polarized emission spectroscopy, the intensity of both left-handed and right-handed circularly polarized luminescence must be measured simultaneously, while the aforementioned two techniques can only measure either left-handed or right-handed luminescence individually. In transient circularly polarized luminescence, the difference between the left-handed and right-handed luminescence is very small, typically less than 1%, and sometimes even less than 1‰. This tiny signal difference can easily be drowned out by signal jitter or random noise. Circular polarization modulation is typically performed using a quarter-wave plate or photoelastic modulator. However, due to the inherent frequency limitations of photoelastic modulators, they are generally unsuitable for measurements in the nanosecond to microsecond timescale. Furthermore, the rotation of the quarter-wave plate can lead to repeated positioning and misalignment of the spatial optical paths of the left-handed and right-handed circularly polarized luminescence, which can easily introduce new errors into the measurement process.

[0004] Therefore, in the process of measuring nanosecond transient circularly polarized emission spectra, there is an urgent need for a measuring instrument that can simultaneously measure left-handed circularly polarized luminescence and right-handed circularly polarized luminescence with low error and high detection efficiency. This instrument will become an efficient means to study chiral luminescence. Summary of the Invention

[0005] The purpose of the present invention is to provide a gated dual-path nanosecond transient circularly polarized emission spectrometer for the field of chiral luminescence measurement, which can be widely used in the research of chiral materials in organic light-emitting diodes (OLEDs), spintronic devices and biosensors.

[0006] The gated dual-light-path nanosecond transient circularly polarized emission spectrometer of the present invention comprises:

[0007] An excitation device, used to excite the sample to emit light and converge the luminous beam into parallel light;

[0008] A beam splitter, for equally splitting the parallel light into two luminous beams, for respectively measuring left-handed and right-handed circularly polarized light;

[0009] The left-handed circularly polarized light collecting device is used to select and converge the left-handed circularly polarized light from one equally divided light beam; the right-handed circularly polarized light collecting device is used to select and converge the right-handed circularly polarized light from the other equally divided light beam;

[0010] a left-handed circularly polarized light detection device for performing photoelectric detection after monochromatizing light of a desired wavelength in the left-handed circularly polarized light spectrum; a right-handed circularly polarized light detection device for performing photoelectric detection after monochromatizing light of a desired wavelength in the right-handed circularly polarized light spectrum;

[0011] A dual-path gate delay integration device for collecting signals from the left-handed circularly polarized light detection device and the right-handed circularly polarized light detection device; and

[0012] A computer is used for analyzing, graphically displaying and storing the signals collected by the dual-channel gate delay integration device.

[0013] Preferably, the excitation device comprises a polarizing element, a first focusing element, a sample cell, a disturbance device and a second focusing element, and the sample cell is used for placing the sample.

[0014] Preferably, the disturbance device is a magnetic stirring device and / or an XZ two-dimensional platform. The magnetic stirring device drives the magnetic stirring bar in the sample pool to make the liquid sample flow locally, thereby reducing the photodamage of the sample molecules; the XZ two-dimensional platform moves two-dimensionally in a direction perpendicular to the light beam, so that the excitation light will not continue to hit the same position of the sample, thereby reducing the photodamage of the sample molecules.

[0015] Preferably, the beam splitting device is a broadband beam splitter, and the beam splitter fraction ratio is 50 / 50.

[0016] Preferably, the left-handed circularly polarized light collecting device and the right-handed circularly polarized light collecting device both include a circular polarization analyzer element, a linear polarization analyzer element, a filter element and a third focusing element.

[0017] Preferably, the circular polarization analyzer is an achromatic quarter-wave plate, which converts left-handed and right-handed circularly polarized light components in the sample light into linearly polarized light.

[0018] Preferably, the linear polarization analyzing element is a Glan-Taylor prism, a Glan-Thompson prism or a wire-grid polarizer, which is used to filter out the linearly polarized light converted from left-handed / right-handed circularly polarized light.

[0019] Preferably, the left-handed circularly polarized light detection device and the right-handed circularly polarized light detection device both include a monochromatic device and a detector, the monochromatic device performs monochromatic processing on the light of the required wavelength in the left-handed / right-handed circularly polarized light spectrum, and the detector is used to detect the left-handed / right-handed circularly polarized light of the light of the required wavelength screened out by the monochromatic device.

[0020] Preferably, the monochromator is two independent monochromators, and the detector is two independent detectors respectively mounted on the two monochromators; or the monochromator is one monochromator, and the detector is a 1×2 detection array.

[0021] Preferably, a gate pulse signal is set in the dual-channel gate delay integration device to integrate the signal in the gate, and the integrated signal data is output after multi-pulse accumulation. By gate delay scanning, the measurement of nanosecond transient luminescence can be achieved.

[0022] Compared with the existing single-channel measurement, the present invention has the following advantages:

[0023] 1. The present invention avoids the systematic errors caused by the repeated positioning deviation of the wave plate, the misalignment of the spatial optical path, and the slight damage of the sample in the left-handed / right-handed single-path measurement, thereby reducing the errors caused by human operation during the experiment;

[0024] 2. The present invention reduces the deviation caused by the difference between the front and back samples in the left-handed / right-handed measurement;

[0025] 3. The present invention can simultaneously measure left-handed circularly polarized luminescence and right-handed circularly polarized luminescence, which reduces measurement time and improves measurement efficiency;

[0026] 4. The present invention adopts gate integration measurement, which reduces the measurement error to the greatest extent through the double accumulation of gate integration and multi-pulse accumulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic structural diagram of a gated dual-path nanosecond transient circularly polarized emission spectrometer according to a preferred embodiment of the present invention;

[0028] Figure 2 A schematic structural diagram of an excitation device according to a preferred embodiment of the present invention;

[0029] Figure 3 This is a schematic structural diagram of a left-handed / right-handed circularly polarized light collecting device according to a preferred embodiment of the present invention;

[0030] Figure 4 This is a schematic structural diagram of a left-handed / right-handed circularly polarized light detection device according to a preferred embodiment of the present invention;

[0031] Figure 5 A schematic diagram of the working principle of a dual-channel gate delay integration device according to a preferred embodiment of the present invention;

[0032] Figure 6 This is a schematic structural diagram of a gated dual-path nanosecond transient circularly polarized emission spectrometer according to a typical embodiment of the present invention; DETAILED DESCRIPTION

[0033] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings and examples, but the protection scope of the present invention should not be limited thereto.

[0034] Figure 1 The schematic diagram of the structure of the gated dual-path nanosecond transient circular polarization emission spectrometer of the preferred embodiment of the present invention is shown. Preferably, the gated dual-path nanosecond transient circular polarization emission spectrometer comprises: an excitation device 1, a beam splitting device 2, a left-handed circularly polarized light collecting device 3 and a right-handed circularly polarized light collecting device 3', a left-handed circularly polarized light detecting device 4 and a right-handed circularly polarized light detecting device 4', a dual-path gate delay integration device 5 and a computer (computer control unit) 6. Figure 2-5 Describe each component in detail.

[0035] Figure 2 This is a schematic structural diagram of the excitation device of a preferred embodiment of the present invention. The excitation device 1 is used to excite the sample to emit light and converge the luminous beam into parallel light. Preferably, the excitation device 1 includes a polarizing element 11, a first focusing element 12, a sample pool 13, a perturbation device 14 and a second focusing element 15. The polarizing element 11 is used to convert the excitation light into linearly polarized light, and can preferably be a Glan Taylor prism, a Glan Thompson prism or a wire grid polarizer. The first focusing element 12 is used to converge the excitation light onto the sample to excite the sample to emit light. Preferably, the first focusing element 12 can be an optical lens, a concave reflector or an off-axis parabolic mirror. The sample pool 13 is used to place the sample, and the thickness of the sample in the sample pool is about 1-2 mm.

[0036] Preferably, the disturbance device 14 is a magnetic stirring device and / or an XZ two-dimensional platform. The magnetic stirring device drives the magnetic stirring rod in the sample pool 13 to make the liquid sample flow locally, thereby reducing the photodamage to the sample molecules. The XZ two-dimensional platform moves two-dimensionally in a direction perpendicular to the light beam, so that the excitation light does not continue to hit the same position of the sample, thereby reducing the photodamage to the sample molecules. The second focusing element 15 is used to converge the light emitted by the sample into parallel light. Preferably, the second focusing element 15 can be an uncoated optical lens. More preferably, the material of the second focusing element 15 has no energy absorption in the excitation band.

[0037] Preferably, the beam splitter 2 is used to split the parallel light (sample light) into two equal beams, one for left-handed and the other for right-handed circularly polarized light measurement. Preferably, the beam splitter 2 is a broadband beam splitter with a 50 / 50 split ratio.

[0038] Figure 3 The diagram is a structural diagram of a left-handed / right-handed circularly polarized light collecting device according to a preferred embodiment of the present invention. The left-handed circularly polarized light collecting device 3 is used to select and converge the left-handed circularly polarized light from one equally divided light beam; the right-handed circularly polarized light collecting device 3' is used to select and converge the right-handed circularly polarized light from another equally divided light beam. Both the left-handed / right-handed circularly polarized light collecting devices 3 and 3' include a circular polarization analyzer element 31, a linear polarization analyzer element 32, a filter element 33 and a third focusing element 34. Preferably, the circular polarization analyzer element 31 is an achromatic quarter-wave plate, and by rotating the fast axis direction of the achromatic quarter-wave plate 31, the left-handed / right-handed circularly polarized light component in the sample light emission can be converted into linearly polarized light. Among them, the circular polarization analyzer 31 in the left-handed circularly polarized light collecting device 3 converts the left-handed circularly polarized light component in the sample light into linearly polarized light; and the circular polarization analyzer 31 in the right-handed circularly polarized light collecting device 3' converts the right-handed circularly polarized light component in the sample light into linearly polarized light. Preferably, the linear polarization analyzer 32 can be a Glan Taylor prism, a Glan Thompson prism or a wire grid polarizer, which is used to filter out the linear polarized light converted from the left-handed / right-handed circularly polarized light. The filter element 33 is preferably a long-pass filter or a band-pass filter, which is used to filter out the residual excitation light in the optical path. The third focusing element 34 can preferably be an optical lens, a concave reflector or an off-axis parabolic mirror, which is used to converge the light in the optical path to the left-handed / right-handed circular polarization detection device 4, 4'.

[0039] Figure 4The diagram is a structural diagram of a left-handed / right-handed circularly polarized light detection device according to a preferred embodiment of the present invention. The left-handed / right-handed circularly polarized light detection devices 4 and 4' each include a monochromator 41 and a detector 42. Preferably, the monochromator 41 performs monochromatic processing on the light of the desired wavelength in the left-handed / right-handed circularly polarized light spectrum. The detector 42 is used to detect the left-handed / right-handed circularly polarized light of the desired wavelength screened out by the monochromator 41 and form electrical signals respectively. In a preferred embodiment, the monochromator 41 is two independent monochromators, and the detector 42 is two independent detectors, which are respectively mounted on the two monochromators. In another preferred embodiment, the monochromator 41 is a monochromator, and the detector 42 is a 1×2 detection array. After the left-handed / right-handed circularly polarized light is converted into linearly polarized light, it enters the monochromator in an upper and lower arrangement, and then the desired wavelength is screened out and enters the detection array respectively. Preferably, the detector 42 is a photomultiplier tube (PMT) or a photomultiplier tube array (1×2 PMT array).

[0040] Figure 5 The schematic diagram of the working principle of the dual-channel gate delay integration device of the preferred embodiment of the present invention is shown in FIG. 1 , wherein (a) is a schematic diagram of the electrical signal output by the detector and the detection gate pulse signal, and (b) is a schematic diagram of the gate pulse integration detection. The dual-channel gate delay integration device 5 has a built-in measurement window (gate pulse signal) that measures the gate signal (the signal output by the detector 42) C j The integrated data is integrated, and multiple pulses (n pulses) are accumulated and outputted. By gate delay scanning, the measurement of nanosecond transient luminescence can be achieved.

[0041] Preferably, the computer 6 is used to analyze, graphically display and store the signals collected by the dual-path gate delay integration device 5. More preferably, the computer 6 can control the gate delay and signal collection of the dual-path gate delay integration device 5.

[0042] The following combination Figure 1-5 The specific process of realizing nanosecond transient circularly polarized emission spectrum measurement by the present invention is described in detail. First, the excitation light enters the excitation device 1 of the gated dual-light path nanosecond transient circularly polarized emission spectrometer of the present invention. In the excitation device 1, the excitation light passes through the polarizing element 11 and is converged onto the sample in the sample pool 13 through the first focusing element 12, exciting the sample to generate luminescence. The luminescence contains a variety of polarization components, such as linear polarization, left-handed circularly polarized light, right-handed circularly polarized light, etc. The disturbance device 14 in the excitation device 1 provides flow or movement to the sample in the sample pool 13, reducing the light damage of the excitation light to the sample. These light beams with different polarization characteristics are converged into parallel light beams through the second focusing element 15 and then enter the beam splitting device 2. The beam splitting device 2 divides the light into two parts at 50 / 50. The two parts of light enter the left-handed / right-handed circularly polarized light collecting devices 3 and 3' respectively.

[0043] In the left-handed / right-handed circularly polarized light collecting device 3, 3', the light first passes through the circular polarization detection element 31, which converts the corresponding left-handed / right-handed circularly polarized light into linearly polarized light, and then passes through the linear polarization detection element 32 to filter out the linear polarized light that meets the requirements. Afterwards, the light in the collection device passes through the color filter element 33, filters out the residual excitation light, and then converges to the left-handed / right-handed circularly polarized light detection device 4, 4' through the third focusing element 34. In the detection device, the two beams of light pass through the monochromatic device 41 to filter out the light of the required wavelength, and then enter the detector 42 for photoelectric detection, converting the optical signal into an electrical signal. The two converted electrical signals enter the dual-channel gate delay integration device 5. In the dual-channel gate delay integration device 5, a gate pulse signal is provided to integrate the signal inside the gate (multi-channel accumulation). As shown Figure 5 As shown, for example, in digital signal measurement, if there are m channels in the gate, the signal values of these m channels are accumulated, and then the signals generated by n consecutive pulse excitations are summed and output to the computer 6. By electronically delaying the movement of the gate, the signal scanning in time can be completed.

[0044] Figure 6This is a schematic diagram of the structure of a gated dual-path nanosecond transient circularly polarized emission spectrometer of a typical embodiment of the present invention. The following will be described in detail from the light source to data acquisition. Here, the present invention takes a Yb femtosecond laser (200kHz, 1030nm) as an example of a light source. First, a Yb femtosecond pulsed light laser 10 generates a femtosecond pulse beam with a central wavelength of 1030nm. The pulsed laser enters an optical parametric amplifier 20 to generate light of the required wavelength, such as 400nm. The excitation light passes through a Glan Taylor prism 11 to generate linearly polarized excitation light. Subsequently, the excitation light passes through a fused quartz convex lens 12 to focus the excitation light onto the sample, which is placed in a fused quartz cuvette (sample cell) 13. A magnetic stirrer (not shown) is installed in the cuvette 13, and a magnetic stirring device 14 is installed outside the cuvette 13. The magnetic stirring device 14 drives the magnetic stirrer to disturb the flow of the liquid sample and reduce the light damage to the sample caused by the pulsed excitation light. The excitation light is focused on the sample to stimulate the sample to emit light. The light contains multiple polarization components such as linear polarization, left-handed circular polarization, and right-handed circular polarization. The light emitted by the sample is converged into a parallel beam by an uncoated fused silica convex lens 15 and then enters a broadband 50 / 50 beam splitter 2, which splits the beam into two beams. The two beams enter the left-handed / right-handed circularly polarized light collection device 3 and 3' respectively. In the left-handed / right-handed circularly polarized light collection device 3 and 3', the light beam first passes through an achromatic quarter-wave plate 31 to convert the left-handed / right-handed circularly polarized light among the multiple polarization components into linear polarized light. It then passes through a Glan Taylor prism 32, and the angle of the Glan Taylor prism is adjusted to filter out the linear polarized light converted above. The filtered linearly polarized light then passes through a long-pass filter 33, preferably the long-pass filter 33 can be LP420 nm, to filter out the residual excitation light. At this point, the two beams contain the required left-handed / right-handed circular polarization information, filter out unnecessary polarization information, and filter out unnecessary residual excitation light. Two beams of linearly polarized light containing left-handed and right-handed circular polarization information are focused by a fused silica convex lens 34 and then enter a monochromator 41. After being filtered by monochromator 41 to select the desired wavelength, the light enters a photomultiplier tube 42 for photoelectric detection, converting the optical signal into an electrical signal. Preferably, the monochromator 41 and the photomultiplier tube 42 are of the same model.

[0045] The converted two-way electrical signal enters the dual-channel gate delay integration device 5. In the dual-channel gate delay integration device 5, a gate pulse signal is set, and the signal in the gate (the electrical signal output by the detector) is integrated (multi-channel accumulation). For example, if there are m channels in the gate, the signal values C of these m channels are integrated. j Add up and get Here i represents the electronic delay of the gate pulse relative to the excitation light, m represents the total number of channels, and then the signals generated by the continuous n pulse excitations are summed to obtain Finally, the results are output to computer 6. By delaying the electronic movement of the gate, the signal scanning in time can be completed, and the left-handed and right-handed kinetic curves can be obtained respectively. The asymmetry factor of the nanosecond transient circularly polarized emission spectrum can be obtained by the following formula:

[0046]

[0047] In the above formula (1), I L (t) represents the intensity of left-handed circularly polarized light at time t, I R (t) represents the intensity of right-handed circularly polarized light at time t.

[0048] When the system is first measured, it is necessary to calibrate the system. First, a sample without chiral luminescence is selected as the standard molecule. The standard molecule solution is placed in the sample cell and the kinetic process of the left-handed circularly polarized luminescence of the standard is obtained by measurement. L (t)0 and the dynamics of right-handed circularly polarized luminescence I R (t) 0, thus obtaining the calibration curve of circularly polarized luminescence. Then, the test curves I of other test samples are calculated based on the circularly polarized luminescence calibration curve of the standard molecule. L (t)1 and I R (t)1 for calibration:

[0049]

[0050]

[0051] The asymmetry factor of the corrected nanosecond transient circularly polarized emission spectrum can be obtained by the above formulas (2) and (3).

[0052] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any person skilled in the art may make various modifications and alterations without departing from the spirit and scope of the present invention. The scope of protection of the present invention shall be determined by the scope of protection defined in the claims.

Claims

1. A gated dual-path nanosecond transient circularly polarized emission spectrometer, characterized in that: include: An excitation device, used to excite the sample to emit light and converge the luminous beam into parallel light; A beam splitter, for equally splitting the parallel light into two luminous beams, for respectively measuring left-handed and right-handed circularly polarized light; The left-handed circularly polarized light collecting device is used to select and converge the left-handed circularly polarized light from one equally divided light beam; the right-handed circularly polarized light collecting device is used to select and converge the right-handed circularly polarized light from the other equally divided light beam; a left-handed circularly polarized light detection device for performing photoelectric detection after monochromatizing light of a desired wavelength in the left-handed circularly polarized light spectrum; a right-handed circularly polarized light detection device for performing photoelectric detection after monochromatizing light of a desired wavelength in the right-handed circularly polarized light spectrum; A dual-path gate delay integration device, used to respectively collect signals from the left-handed circularly polarized light detection device and the right-handed circularly polarized light detection device; as well as A computer is used for analyzing, graphically displaying and storing the signals collected by the dual-channel gate delay integration device.

2. The gated dual-light-path nanosecond transient circularly polarized emission spectrometer according to claim 1, characterized in that: The excitation device comprises a polarizing element, a first focusing element, a sample pool, a disturbance device and a second focusing element, and the sample pool is used for placing a sample.

3. The gated dual-light-path nanosecond transient circularly polarized emission spectrometer according to claim 2, characterized in that: The disturbance device is a magnetic stirring device and / or an XZ two-dimensional platform. The magnetic stirring device drives the magnetic stirring bar in the sample pool to make the liquid sample flow locally, thereby reducing the light damage to the sample molecules; the XZ two-dimensional platform moves two-dimensionally in a direction perpendicular to the light beam, so that the excitation light will not continue to hit the same position of the sample, thereby reducing the light damage to the sample molecules.

4. The gated dual-light-path nanosecond transient circularly polarized emission spectrometer according to claim 1, characterized in that: The beam splitting device is a broadband beam splitter, and the beam splitter fraction ratio is 50 / 50.

5. The gated dual-path nanosecond transient circularly polarized emission spectrometer according to claim 1, characterized in that: The left-handed circularly polarized light collecting device and the right-handed circularly polarized light collecting device both include a circular polarization analyzing element, a linear polarization analyzing element, a filter element, and a third focusing element.

6. The gated dual-light-path nanosecond transient circularly polarized emission spectrometer according to claim 5, characterized in that: The circular polarization analyzer is an achromatic quarter-wave plate, which converts the left-handed and right-handed circularly polarized light components in the sample light into linearly polarized light.

7. The gated dual-light-path nanosecond transient circularly polarized emission spectrometer according to claim 5, characterized in that: The linear polarization analyzing element is a Glan-Taylor prism, a Glan-Thompson prism or a wire grid polarizer, and is used to filter out the linear polarized light converted from left-handed / right-handed circularly polarized light.

8. The gated dual-light-path nanosecond transient circularly polarized emission spectrometer according to claim 1, characterized in that: The left-handed circularly polarized light detection device and the right-handed circularly polarized light detection device both include a monochromatic device and a detector. The monochromatic device performs monochromatic processing on the light of the required wavelength in the left-handed / right-handed circularly polarized light spectrum, and the detector is used to detect the left-handed / right-handed circularly polarized light of the light of the required wavelength screened out by the monochromatic device.

9. The gated dual-light-path nanosecond transient circularly polarized emission spectrometer according to claim 8, characterized in that: The monochromator is two independent monochromators, and the detector is two independent detectors respectively mounted on the two monochromators; or the monochromator is one monochromator, and the detector is a 1×2 detection array.

10. The gated dual-path nanosecond transient circularly polarized emission spectrometer according to claim 1, characterized in that: A gate pulse signal is set in the dual-channel gate delay integration device to integrate the signal in the gate, and the integrated signal data is output after multi-pulse accumulation. Through gate delay scanning, the measurement of nanosecond transient luminescence can be achieved.

Images