CN114544152A - Observation device and observation method for light output state of far-infrared laser chip - Google Patents

Abstract

The invention belongs to the technical field of far infrared measurement, in particular to an observation device and an observation method for the light-emitting state of a far infrared laser chip, which comprises a lens, an optical filter, a thermal detection array, a shell, a mobile station and a computer, wherein the optical filter is arranged on the shell; the lens images the end face of the detected far infrared laser chip, and the optical filter is used for filtering redundant infrared background radiation generated by the detected far infrared laser chip and a surrounding background thereof; during observation, the lens, the optical filter and the thermal detection array are arranged on the shell, the position of the whole observation device is moved through the mobile station, an image of the end face of the detected far infrared laser chip is positioned on the thermal detection array, the driving voltage or current of the detected far infrared laser chip is adjusted, the light emitting state of the laser chip is changed, light emitting spot information under different states is respectively recorded on the thermal detection array, and the size of a light spot, the light emitting intensity and the change of the light spot and the change of the light emitting intensity and the change of the light spot along with time are included, so that the observation of the light emitting state of the far infrared laser chip is realized.

Description

Observation device and observation method for light output state of far-infrared laser chip

technical field

The invention belongs to the technical field of far-infrared measurement, in particular to an observation device and an observation method for the light-emitting state of a far-infrared laser chip, which are used for measuring the light-emitting performance of a far-infrared laser chip.

Background technique

The far-infrared laser chip is one of the important light sources for active detection and imaging in the even-long wave band. Its working wavelength mainly covers more than 20 microns, which is limited by the maturity and process level of the chip preparation materials. The current far-infrared laser chips, especially semiconductor lasers It is still difficult for chips to work at room temperature, and the yield of chip material growth and chip process preparation is still low, and there is a greater demand for light emission testing of different batches of chips, especially chips prepared from materials with different active area structures. Whether the chip emits light and the level of light output are qualitatively and quantitatively measured.

Since the electromagnetic radiation in the far-infrared band is invisible, it cannot be easily and quickly observed with the naked eye or visible light camera. There are two commonly used methods at present: one is to judge the chip by analyzing the current-voltage (I-V) curve of the chip. Whether it emits light or not, but this method has a large error, and the judgment is often inaccurate, because the preparation process of chips with different active area structures has certain differences, resulting in a large difference in the I-V curve of the chip, and this method cannot be judged. The size of the light output power of the chip can only roughly judge the working performance of the chip; the second method is to judge the light output state of the chip by measuring the emission spectrum of the chip. , the threshold current or voltage of light output, and the relative magnitude of light output power are relatively common and reliable measurement methods. It is cumbersome, and this method cannot obtain real-time observation results and is difficult to achieve rapid measurement, and it is difficult to be competent for the rapid screening of large quantities of chips. Therefore, developing a device and an observation method that can observe whether the laser chip emits light, the power of the light, and the quenching of the light in real time is an urgent problem to be solved in the current far-infrared laser chip performance test and chip screening.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide an observation device and an observation method for the light output state of a far-infrared laser chip, which overcomes the shortcomings of the existing system that the measurement process is cumbersome, the chip screening speed is slow, and the real-time observation results cannot be obtained. For the rapid measurement and rapid screening of the light-emitting state of the chip, the present invention adopts a thermal detection array that can work in real time, and realizes the real-time observation of the light-emitting state of the far-infrared laser chip by filtering out the background infrared radiation; by configuring a high-resistance silicon lens and a three-dimensional translation stage , to achieve accurate observation and analysis of the light output state of different chips. Compared with the traditional method, the observation effect and chip screening speed are greatly improved.

The specific technical scheme adopted by the present invention is as follows: a device for observing the light output state of a far-infrared laser chip, comprising a lens, a filter, a thermal detection array, a translation stage and a computer, and the lens, the filter and the thermal detection array are arranged on the translation stage The lens and the filter are perpendicular to the translation stage, and the filter is arranged between the lens and the thermal detection array, and the thermal detection array is connected to the computer with the imaging software installed in a wired or wireless manner; it also includes a housing, the housing is set On the translation stage, the lens, filter and thermal detection array are housed in the housing.

In the above technical solution, the lens images the end face of the far-infrared laser chip under test, and the filter is used to filter out the redundant infrared background radiation generated by the end face of the far-infrared laser chip under test and its surrounding objects; during observation, the lens, filter The light sheet and the thermal detection array are installed on the casing, and the position of the entire observation device is moved through the mobile stage, so that the image of the end face of the far-infrared laser chip to be measured is located on the thermal detection array, and the electrical signal generated on the thermal detection array is connected to the computer. , controlled by the imaging software on the computer; adjust the driving voltage or current of the far-infrared laser chip under test, so that the light output state of the laser chip changes, and record the light spot information in different states on the thermal detection array, including the size of the light spot, The intensity of the light output and the change of the two with time, so as to realize the observation and analysis of the light output state of the far-infrared laser chip.

In a further improvement of the present invention, the lens is a plano-convex lens, preferably a high-resistance silicon lens coated on both sides; the optical filter is a thin paper sheet.

In a further improvement of the present invention, the working wavelength of the thermal detection array is 30 μm-300 μm; the material of the casing is aluminum alloy; and the mobile stage is a three-dimensional translation stage.

The invention also discloses a method for observing the light-emitting state of the far-infrared laser chip, using the above-mentioned observation device for the light-emitting state of the far-infrared laser chip, which specifically includes the following steps:

Step 1: Install the lens and the thermal detection array on the housing, and install the housing on the mobile platform to form a three-dimensional position-movable far-infrared radiation observation device;

Step 2: Adjust the mobile stage so that the image of the light-emitting end face of the far-infrared laser chip just falls on the thermal detection array, and is clearly observed by the control software on the computer;

Step 3: insert the filter from the top of the housing to filter out excess infrared background radiation;

Step 4: Adjust the driving voltage or current of the far-infrared laser chip under test, so that the light output state of the laser chip changes. According to the description in step 2, the image of the laser spot output from the end face of the far-infrared laser chip under test is also located in the thermal detector. on the array;

Step 5: Record the light spot information in different states, including the size of the light spot, the intensity of the light output, and the changes of the two over time, respectively, through the control software of the computer.

Beneficial effects of the present invention:

(1) The observation device and observation method of the light-emitting state of the far-infrared laser chip of the present invention use a device composed of a thermal detection array and a double-sided coated plano-convex high-resistance silicon lens to observe the light-emitting state of the far-infrared laser chip It has the advantages of small energy loss, more realistic reflection of the laser state of the light-emitting end face, real-time observation, clear recording of the two-dimensional energy distribution corresponding to the light-emitting state, and good recording effect of the continuous change of the light-emitting state.

(2) The device and method for observing the light output state of a far-infrared laser chip according to the present invention use a casing to combine a high-resistance silicon lens, an optical filter, and a thermal detection array, and assemble it into a whole with a three-dimensional translation stage, so that the observation The applicability of the device is stronger, and it can quickly observe and analyze the light-emitting state of chips in different positions on the same low-temperature device and chips on different low-temperature devices, so that the observation speed of the light-emitting state of the chip is fast, and the chip screening speed is fast.

(3) The device and method for observing the light-emitting state of the far-infrared laser chip of the present invention adopts the setting of the plug-in filter, so that during the observation process of the entire light-emitting state, the entire infrared A clear image of the background to further calibrate the far-infrared image when the filter is inserted ensures the accuracy of the observations.

Description of drawings

Figure 1 is a schematic structural diagram of the present invention.

Fig. 2 is the observation result diagram before and after the far-infrared laser chip obtained by adopting the observation device and the observation method proposed by the present invention, wherein (a) no filter is inserted before the light is emitted, and (b) the filter is not inserted before the light is emitted , (c) is no filter inserted after the light is emitted, (d) is the filter inserted after the light is emitted.

3 is a light spot image (a) of a far-infrared laser chip and an energy intensity distribution curve (b) at the center of the spot (white dotted line) obtained by using the observation device and observation method proposed by the present invention.

In Figure 1: 1- The end face of the far-infrared laser chip to be measured, 2- Lens, 3- Optical filter, 4- Thermal detection array, 5- Housing, 6- Mobile stage, 7- Computer.

Detailed ways

In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments are only used to explain the present invention and do not limit the protection scope of the present invention.

Example: As shown in Figure 1, a device for observing the light output state of a far-infrared laser chip includes a lens 2, a filter 3, a thermal detection array 4, a housing 5, a mobile station 6 and a computer 7; The far-infrared laser chip end face 1 is used for imaging, and the filter 3 is used to filter out the excess infrared background radiation generated by the far-infrared laser chip end face and its surrounding objects; during observation, the lens 2, the filter 3 and the thermal detection array 4 It is installed on the casing 5, and the position of the entire observation device is moved by the mobile stage 6, so that the image of the end face of the far-infrared laser chip to be measured is located on the thermal detection array 4, and the electrical signal generated on the thermal detection array 4 is connected to the computer 7, It is controlled by the imaging software on the computer 7; the driving voltage or current of the far-infrared laser chip to be measured is adjusted, so that the light-emitting state of the laser chip changes, and the light-emitting light spot information in different states is recorded on the thermal detection array 4, including the size of the light spot. , the intensity of the light output and the change of the two with time, so as to realize the observation and analysis of the light output state of the far-infrared laser chip.

The measured far-infrared laser chip end face 1 is a cleavage surface of the semiconductor material. Optionally, the measured far-infrared laser chip end face is in the order of hundreds of microns.

The lens 2 is a plano-convex lens, and the material is high-resistance silicon. Optionally, the diameter of the lens 2 is 15mm and the focal length is 15mm. Preferably, the front and rear surfaces of the lens 2 are vapor-deposited with a far-infrared band antireflection film; filter; 3 is a thin paper sheet, preferably, the thickness of the filter 3 is 40 μm; the working wavelength of the thermal detection array 4 is 30 μm-300 μm, preferably, the frame rate of the thermal detection array 4 is 25 Hz, and the pixel size is 17 μm , the pixels are 384×288; the material of the casing 5 is aluminum alloy, and optionally, the surface of the casing 5 is prepared by a blackening process.

The application of this embodiment is used to realize the observation and analysis of the light spot emitted by the far-infrared laser chip, and the specific observation method includes the following steps:

Step 1: Install the lens and the thermal detection array on the housing, and install the housing on the mobile platform to form a far-infrared radiation observation device that can move in three-dimensional position;

Step 2: Adjust the mobile stage so that the image of the light-emitting end face of the far-infrared laser chip just falls on the thermal detection array, and is clearly observed through the control software on the computer;

Step 3: Insert a filter from the top of the housing to filter out excess infrared background radiation;

Step 4: Adjust the driving voltage or current of the far-infrared laser chip under test, so that the light output state of the laser chip changes. According to the description in step 2, the image of the laser spot output from the end face of the far-infrared laser chip under test is also located on the thermal detection array. ;

Step 5: Record the light spot information in different states through the control software on the computer, including the size of the light spot, the light intensity and the changes of the two with time.

The operating wavelength of the far-infrared laser chip to be tested is 81 μm, and the mobile stage is a three-dimensional translation stage. The movement accuracy of the three dimensions is 10 μm, and the movement stroke is 100 mm. Using the above observation method and the movement parameters of the three-dimensional translation stage, the accuracy of the three-dimensional translation stage is realized. The real-time observation of whether the far-infrared laser chip emits light or not, the observation results are shown in Figure 2, in which (a) no filter is inserted before the light is emitted, (b) the filter is not inserted before the light is emitted, and (c) is not inserted after the light is emitted. Insert the filter, (d) is to insert the filter after the light is emitted; using the observation device and observation method, the analysis of the light spot of the far-infrared laser chip is also realized. The analysis result is shown in Figure 3, where (a) is the light output Spot image, (b) is the energy intensity distribution curve at the center of the spot (white dashed line). From the energy distribution curve in Figure 3(b), it can be seen that the light spot of the far-infrared laser chip under test contains multiple secondary Spot, in which the half-height width Δp1 of the main spot is 36 pixel intervals, calculated according to the pixel pitch of 17 μm, corresponding to Δp1 = 612 μm, the half-height width Δp2 of the secondary spot is 9 pixel intervals, and Δp2 = 153 μm is calculated. Therefore, the observation device and the observation method proposed in the present invention realize the observation of the light output state of the far-infrared laser chip and the analysis of the light output spot.

The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the descriptions in the above-mentioned embodiments and the description are only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have Various changes and modifications fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (9)

1. an observation device of a far-infrared laser chip light-emitting state, is characterized in that, comprises lens, filter, thermal detection array, translation stage and computer, and described lens, filter and thermal detection array are arranged on the translation stage , the lens and the filter are perpendicular to the translation stage, the filter is arranged between the lens and the thermal detection array, and the thermal detection array is connected to the imaging device installed in a wired or wireless manner software on the computer. 2 . The device for observing the light-emitting state of a far-infrared laser chip according to claim 1 , further comprising a casing, the casing is arranged on the translation stage, and the lens and the filter are packaged in the casing. 3 . and thermal detection arrays. 3 . The device for observing the light output state of a far-infrared laser chip according to claim 2 , wherein the lens is a plano-convex lens. 4 . 4 . The device for observing the light output state of a far-infrared laser chip according to claim 2 , wherein the lens is a high-resistance silicon lens coated on both sides. 5 . 5 . The device for observing the light output state of a far-infrared laser chip according to claim 3 or 4 , wherein the filter is a thin paper sheet. 6 . 6 . The device for observing the light output state of a far-infrared laser chip according to claim 5 , wherein the thermal detection array adopts a thermal detection array with an operating wavelength of 30 μm-300 μm. 7 . 7 . The device for observing the light-emitting state of a far-infrared laser chip according to claim 6 , wherein the casing is made of an aluminum alloy material. 8 . 8 . The device for observing the light-emitting state of a far-infrared laser chip according to claim 7 , wherein the translation stage is an electric three-dimensional translation stage. 9 . 9. A method for observing the light-emitting state of a far-infrared laser chip, characterized in that, using the observation device for the light-emitting state of a far-infrared laser chip as claimed in claim 8, specifically comprising the following steps: Step 1: Install the lens and the thermal detection array on the housing, and install the housing on the mobile platform to form a three-dimensional position-movable far-infrared radiation observation device; Step 2: Adjust the mobile stage so that the image of the light-emitting end face of the far-infrared laser chip just falls on the thermal detection array, and is clearly observed by the control software on the computer; Step 3: insert the filter from the top of the housing to filter out excess infrared background radiation; Step 4: Adjust the driving voltage or current of the far-infrared laser chip under test, so that the light output state of the laser chip changes. According to the description in step 2, the image of the laser spot output from the end face of the far-infrared laser chip under test is also located in the thermal detector. on the array; Step 5: Record the light spot information in different states, including the size of the light spot, the intensity of the light output, and the changes of the two over time, respectively, through the control software of the computer.

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