Method and apparatus for OPO tuning followed by nonlinear frequency conversion

Abstract

This disclosure relates to the fields of optics and laser technology, and particularly to a method and apparatus for OPO tuning followed by nonlinear frequency conversion. The method is applied to a target optical path including an OPO tuning element and its corresponding first motor, a nonlinear frequency conversion element and its corresponding second motor. The method includes: determining, according to the target output wavelength and in a preset mapping relationship, a first target position parameter corresponding to the first motor at the target output wavelength, and a second target position parameter corresponding to the second motor at the target output wavelength; after adjusting the first motor to the position indicated by the first target position parameter and the second motor to the position indicated by the second target position parameter, performing OPO tuning followed by nonlinear frequency conversion using the target optical path to determine output light with the target output wavelength. Embodiments of this disclosure simplify the complexity of optical path adjustment and quickly and accurately obtain output light with different target output wavelengths.

Description

Technical Field

[0001] This disclosure relates to the fields of optics and laser technology, and in particular to a method and apparatus for nonlinear frequency conversion after OPO tuning. Background Technology

[0002] In the field of tunable laser technology, optical systems based on optical parametric oscillation (OPO) combined with nonlinear frequency transformation (e.g., frequency doubling) are an important means of obtaining lasers over a wide wavelength range. However, the practical application of such optical systems is limited by the complexity of their operation and the stability of their output performance. Summary of the Invention

[0003] In view of this, this disclosure proposes a method and apparatus for nonlinear frequency conversion after OPO tuning.

[0004] According to one aspect of this disclosure, a method for OPO tuning followed by nonlinear frequency conversion is provided. The method is applied to a target optical path, which includes: an OPO tuning element, a nonlinear frequency conversion element, a first motor for controlling the OPO tuning element, and a second motor for controlling the nonlinear frequency conversion element. The method includes: determining, based on a target output wavelength and in a preset mapping relationship, a first target position parameter corresponding to the first motor at the target output wavelength and a second target position parameter corresponding to the second motor at the target output wavelength; after the first motor is adjusted to the position indicated by the first target position parameter and the second motor is adjusted to the position indicated by the second target position parameter, performing OPO tuning followed by nonlinear frequency conversion using the target optical path to determine output light having the target output wavelength.

[0005] In one possible implementation, the target optical path further includes a pump source; the method further includes: determining the output wavelength range corresponding to the target optical path based on the pump source, the OPO tuning element, and the nonlinear frequency conversion element; determining multiple calibration output wavelengths within the output wavelength range corresponding to the target optical path; calibrating the first motor and the second motor to determine a first calibration position parameter corresponding to the first motor and a second calibration position parameter corresponding to the second motor at each calibration output wavelength; and fitting the preset mapping relationship based on the first calibration position parameter corresponding to the first motor and the second calibration position parameter corresponding to the second motor at each calibration output wavelength.

[0006] In one possible implementation, calibrating the first motor and the second motor to determine the first calibration position parameter of the first motor and the second calibration position parameter of the second motor for each calibration output wavelength includes: for any calibration output wavelength, driving the first motor and the second motor to scan within their respective position ranges, recording the wavelength and energy of the output light of the target optical path under each position combination; and determining the first calibration position parameter of the first motor and the second calibration position parameter of the second motor under the calibration output wavelength based on the position combination corresponding to the output light of the target optical path having the calibration output wavelength and the maximum energy.

[0007] In one possible implementation, both the first motor and the second motor are voice coil motors.

[0008] In one possible implementation, the nonlinear frequency conversion element is one of the following: a frequency multiplier element or a sum-frequency element.

[0009] According to another aspect of this disclosure, an apparatus for OPO tuning followed by nonlinear frequency conversion is provided. The apparatus is applied to a target optical path, which includes: an OPO tuning element, a nonlinear frequency conversion element, a first motor for controlling the OPO tuning element, and a second motor for controlling the nonlinear frequency conversion element. The apparatus includes: a position parameter determination module, configured to determine, based on a target output wavelength and a preset mapping relationship, a first target position parameter corresponding to the first motor at the target output wavelength and a second target position parameter corresponding to the second motor at the target output wavelength; and an OPO tuning followed by nonlinear frequency conversion module, configured to, after the first motor is adjusted to the position indicated by the first target position parameter and the second motor is adjusted to the position indicated by the second target position parameter, perform OPO tuning followed by nonlinear frequency conversion using the target optical path to determine output light having the target output wavelength.

[0010] In one possible implementation, the target optical path further includes a pump source; the device further includes: an output wavelength range determination module, used to determine the output wavelength range corresponding to the target optical path based on the pump source, the OPO tuning element, and the nonlinear frequency conversion element; a calibration output wavelength determination module, used to determine multiple calibration output wavelengths within the output wavelength range corresponding to the target optical path; a calibration module, used to calibrate the first motor and the second motor, and determine the first calibration position parameter corresponding to the first motor and the second calibration position parameter corresponding to the second motor under each calibration output wavelength; and a fitting module, used to fit the preset mapping relationship based on the first calibration position parameter corresponding to the first motor and the second calibration position parameter corresponding to the second motor under each calibration output wavelength.

[0011] In one possible implementation, the calibration module is specifically used to: drive the first motor and the second motor to scan within their respective position ranges for any given calibration output wavelength, and record the wavelength and energy of the output light of the target optical path under each position combination; and determine the first calibration position parameter corresponding to the first motor and the second calibration position parameter corresponding to the second motor under the given calibration output wavelength based on the position combination corresponding to when the output light of the target optical path has the given calibration output wavelength and the maximum energy.

[0012] In one possible implementation, both the first motor and the second motor are voice coil motors.

[0013] In one possible implementation, the nonlinear frequency conversion element is one of the following: a frequency multiplier element or a sum-frequency element.

[0014] According to embodiments of this disclosure, based on the desired target output wavelength, a first target position parameter corresponding to the first motor used to control the OPO tuning element at the target output wavelength and a second target position parameter corresponding to the second motor used to control the nonlinear frequency conversion element at the target output wavelength are determined in a preset mapping relationship. Thus, after the first motor is adjusted to the position indicated by the first target position parameter and the second motor is adjusted to the position indicated by the second target position parameter, OPO tuning is performed using the target optical path followed by nonlinear frequency conversion, thereby determining the output light with the target output wavelength. Based on the preset mapping relationship, the first and second motors can be used to synchronously and quickly control the OPO tuning element and the nonlinear frequency conversion element, simplifying the complexity of optical path adjustment. Furthermore, output light with different target output wavelengths can be obtained quickly and accurately, improving the stability of output performance.

[0015] Other features and aspects of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0016] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this disclosure together with the specification and serve to explain the principles of this disclosure.

[0017] Figure 1 This diagram illustrates an optical path diagram of an OPO tuned followed by nonlinear frequency conversion in the prior art.

[0018] Figure 2 A flowchart illustrating a method for nonlinear frequency conversion after OPO tuning according to an embodiment of the present disclosure is shown.

[0019] Figure 3 A schematic diagram of a target optical path according to an embodiment of the present disclosure is shown.

[0020] Figure 4 A schematic diagram of a target optical path according to an embodiment of the present disclosure is shown.

[0021] Figure 5 A block diagram is shown of an apparatus for nonlinear frequency conversion after OPO tuning according to an embodiment of the present disclosure. Detailed Implementation

[0022] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0023] As used herein, the terms “comprising,” “including,” “having,” or variations thereof are open-ended and include one or more of the stated features, integrals, elements, steps, components, or functions, but do not exclude the presence or addition of one or more other features, integrals, elements, steps, components, functions, or groups thereof.

[0024] When an element is referred to as “connected,” “coupled,” “responding,” or a variation thereof relative to another element, it may be directly connected, coupled, or responding to another element, or there may be an intermediate element present.

[0025] Although the terms first, second, third, etc., may be used herein to describe various elements / operations, these elements / operations should not be limited by these terms. These terms are only used to distinguish one element / operation from another. Therefore, without departing from the teachings of the inventive concept, a first element / operation in some embodiments may be referred to as a second element / operation in other embodiments.

[0026] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0027] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of this disclosure.

[0028] In the field of tunable laser technology, optical systems based on OPO and combined with nonlinear frequency transformation (e.g., frequency doubling, sum-frequency conversion) are an important means of obtaining lasers with a wide wavelength range. However, the practical application of such optical systems is limited by the complexity of their operation and the stability of their output performance.

[0029] In traditional optical systems that use OPO tuning followed by nonlinear frequency conversion, to achieve laser output at a specific wavelength, the OPO tuning element (e.g., the nonlinear crystal angle or grating) must first be adjusted to set the wavelength of the signal light output after OPO tuning. Subsequently, to obtain the highest possible power output, the subsequent nonlinear frequency conversion element must be finely tuned to operate near the optimal phase-matching condition, i.e., to ensure that the output laser at the specific wavelength has maximum energy. This process is known as optimizing the nonlinear frequency conversion efficiency.

[0030] Figure 1 This diagram illustrates an optical path diagram of an OPO tuned followed by nonlinear frequency conversion in the prior art. Figure 1 The nonlinear frequency conversion element shown is a frequency multiplier element, such as... Figure 1 As shown, laser source 101 emits laser light, which, after passing through the OPO resonant cavity, generates signal light with a certain wavelength range. The wavelength of the signal light is changed by adjusting the angle of the OPO tuning element 102 (e.g., an OPO crystal) within the OPO resonant cavity. A commonly used method is to mount the OPO tuning element 102 (e.g., an OPO crystal) on a stepper motor and use the stepper motor to adjust the angle of the OPO tuning element 102 (e.g., the OPO crystal).

[0031] The signal light generated by the OPO resonant cavity passes through the frequency doubling element 103 (e.g., a frequency doubling crystal) to produce shorter wavelength output light. Currently, the frequency doubling element 103 (e.g., a frequency doubling crystal) is typically mounted on a stepper motor or adjustment frame, and the stepper motor or adjustment frame is used to adjust the frequency doubling element 103 (e.g., the frequency doubling crystal). Specifically, a sampling energy meter 104 is generally used to provide feedback on the energy of the output light of the frequency doubling element 103 (e.g., the frequency doubling crystal) at different angles during the adjustment process, in order to find the maximum energy point and achieve maximum frequency doubling efficiency.

[0032] The existing technology has two main drawbacks: 1. Due to the poor reset accuracy of the stepper motor, it is necessary to find the zero position upon startup (photoelectric detection) and also require an encoder to track the number of steps; 2. The efficiency of the nonlinear frequency conversion is monitored by an energy meter, and the efficiency of the nonlinear frequency conversion element (e.g., frequency multiplier element, sum frequency element) is adjusted based on feedback, making it difficult to achieve repeatability of the nonlinear frequency conversion efficiency.

[0033] This disclosure provides a method for OPO tuning followed by nonlinear frequency conversion, which simplifies the complexity of optical path adjustment, quickly and accurately obtains output light of different target output wavelengths, and improves the stability of output performance. The method for OPO tuning followed by nonlinear frequency conversion according to this disclosure is described in detail below.

[0034] Figure 2 A flowchart illustrating a method for OPO tuning followed by nonlinear frequency conversion according to an embodiment of the present disclosure is shown. The method is applied to a target optical path, which includes: an OPO tuning element, a nonlinear frequency conversion element, a first motor for controlling the OPO tuning element, and a second motor for controlling the nonlinear frequency conversion element; the method includes:

[0035] In step S21, based on the target output wavelength, the first target position parameter of the first motor and the second target position parameter of the second motor at the target output wavelength are determined in a preset mapping relationship.

[0036] In step S22, after the first motor is adjusted to the position indicated by the first target position parameter and the second motor is adjusted to the position indicated by the second target position parameter, the target optical path is used for OPO tuning and then nonlinear frequency transformation to determine the output light with the target output wavelength.

[0037] The first motor used to control the OPO tuning element and the second motor used to control the nonlinear frequency conversion element in the target optical path are pre-calibrated to determine a preset mapping relationship. Based on the preset mapping relationship, the first target position parameters of the first motor and the second target position parameters of the second motor when the target output wavelength and the nonlinear frequency conversion efficiency are highest can be directly determined. This allows for direct position adjustment of the first and second motors, effectively simplifying the optical path adjustment process. Consequently, output light of different target output wavelengths can be obtained quickly and accurately, improving the stability of output performance.

[0038] The specific value of the target output wavelength can be flexibly set according to the actual application scenario, and this disclosure does not impose specific limitations on it.

[0039] In one possible implementation, both the first motor and the second motor are voice coil motors.

[0040] The rotation angle of the voice coil motor has a fixed relationship with the voltage, and can achieve an adjustment at the level of 1mV, with a reset accuracy of 1urad. The adjustment of the first motor used to control the OPO tuning element and the second motor used to control the nonlinear frequency conversion element are both on the order of 100urad. Therefore, compared with the problems of poor reset accuracy and difficulty in achieving repeatability of nonlinear frequency conversion efficiency caused by the use of stepper motors in the prior art, the first motor and the second motor in the target optical path of this disclosure are both voice coil motors, which are accurate in reset and fast in adjustment, and can effectively achieve repeatability of different target output wavelengths and their highest nonlinear frequency conversion efficiency.

[0041] The rotation angle of a voice coil motor has a fixed relationship with voltage. Therefore, when both the first motor and the second motor are voice coil motors, the first target position parameter and the second target position parameter are both voltage values.

[0042] Based on the voltage value indicated by the first target position parameter, the first voice coil motor can be adjusted to the corresponding rotation angle, thereby adjusting the angle of the OPO tuning element; based on the voltage value indicated by the second target position parameter, the second voice coil motor can be adjusted to the corresponding rotation angle, thereby adjusting the angle of the nonlinear frequency conversion element to achieve optimal phase matching.

[0043] In one possible implementation, the target optical path further includes a pump source; the method further includes: determining the output wavelength range corresponding to the target optical path based on the pump source, the OPO tuning element, and the nonlinear frequency conversion element; determining multiple calibration output wavelengths within the output wavelength range corresponding to the target optical path; calibrating the first motor and the second motor, and determining the first calibration position parameter corresponding to the first motor and the second calibration position parameter corresponding to the second motor under each calibration output wavelength; and fitting a preset mapping relationship based on the first calibration position parameter corresponding to the first motor and the second calibration position parameter corresponding to the second motor under each calibration output wavelength.

[0044] Based on the pump source, OPO tuning element, and nonlinear frequency conversion element, the output wavelength range corresponding to the target optical path can be determined. The specific determination process can be found in existing technologies, and this disclosure does not impose specific limitations on it.

[0045] Within the output wavelength range corresponding to the target optical path, multiple calibration output wavelengths can be determined for subsequent calibration. The more calibration output wavelengths there are, the more accurate the calibration results will be, but the computational complexity will be correspondingly higher. Therefore, the specific number of calibration output wavelengths should be flexibly determined according to the actual scenario requirements, and this disclosure does not impose a specific limitation on this.

[0046] The first motor and the second motor are calibrated to determine the first calibration position parameter of the first motor and the second calibration position parameter of the second motor at each calibration output wavelength.

[0047] In one possible implementation, the first motor and the second motor are calibrated to determine the first calibration position parameter of the first motor and the second calibration position parameter of the second motor for each calibration output wavelength. This includes: for any calibration output wavelength, driving the first motor and the second motor to scan within their respective position ranges, and recording the wavelength and energy of the output light of the target optical path under each position combination; and determining the first calibration position parameter of the first motor and the second calibration position parameter of the second motor under the calibration output wavelength based on the position combination corresponding to the output light of the target optical path having the calibration output wavelength and the maximum energy.

[0048] For any given calibrated output wavelength, the first and second motors are driven to scan within their respective position ranges, recording the wavelength and energy of the output light from the target optical path under each position combination. This allows the identification of the position combination where the output light from the target optical path has the calibrated output wavelength and the maximum energy, at which point the nonlinear frequency conversion efficiency is highest. Based on the position combination where the output light from the target optical path has the calibrated output wavelength and the maximum energy, the first calibrated position parameters for the first motor and the second calibrated position parameters for the second motor under that calibrated output wavelength can be determined.

[0049] By iterating through each calibration output wavelength, the first calibration position parameter corresponding to the first motor and the second calibration position parameter corresponding to the second motor are obtained for each calibration output wavelength.

[0050] Based on the first calibration position parameters of the first motor and the second calibration position parameters of the second motor under each calibration output wavelength, a preset mapping relationship is obtained by fitting.

[0051] In one example, the preset mapping relationship includes: output wavelength-first motor position mapping relationship and output wavelength-second motor position mapping relationship.

[0052] In one example, based on the first calibrated position parameters of the first motor at each calibrated output wavelength, an interpolation algorithm is used to fit the output wavelength-first motor position mapping relationship. This output wavelength-first motor position mapping relationship can directly determine the first target position parameters of the first motor when the nonlinear frequency conversion efficiency is highest for different target output wavelengths.

[0053] When the OPO tuning element includes an OPO crystal a, the target optical path includes only a first motor A for controlling the OPO crystal. Based on the above calibration method, the first motor A is calibrated, and the determined output wavelength-first motor position mapping relationship can directly determine the first target position parameter of the first motor A when the nonlinear frequency conversion efficiency is highest for different target output wavelengths.

[0054] When the OPO tuning element includes two OPO crystals a and b, the target optical path includes a first motor A for controlling OPO crystal a and a first motor B for controlling OPO crystal b. Based on the above calibration method, the first motor A and the second motor B are calibrated. The determined output wavelength-first motor position mapping relationship can directly determine the first target position parameters of the first motor A and the first target position parameters of the first motor B when the nonlinear frequency conversion efficiency is highest for different target output wavelengths.

[0055] In one example, based on the second calibration position parameters of the second motor corresponding to each calibration output wavelength, an interpolation algorithm is used to fit the output wavelength-second motor position mapping relationship. This output wavelength-second motor position mapping relationship can directly determine the second target position parameters of the second motor when the nonlinear frequency conversion efficiency is highest for different target output wavelengths.

[0056] When the nonlinear frequency conversion element includes a nonlinear frequency conversion crystal c, only a second motor C for controlling the nonlinear frequency conversion crystal c is included in the target optical path. Based on the above calibration method, the output wavelength-second motor position mapping relationship is calibrated for the second motor C, and the second target position parameter of the second motor C can be directly determined when different target output wavelengths and the highest nonlinear frequency conversion efficiency are achieved.

[0057] When the nonlinear frequency conversion element includes two nonlinear frequency conversion crystals c and d, a second motor C for controlling the nonlinear frequency conversion crystal c and a second motor D for controlling the nonlinear frequency conversion crystal d are included in the target optical path. Based on the above calibration method, the output wavelength-second motor position mapping relationship is calibrated for the second motor C and the second motor D, and the second target position parameter of the second motor C and the second target position parameter of the second motor D can be directly determined when different target output wavelengths and the highest nonlinear frequency conversion efficiency are achieved.

[0058] In one example, the interpolation algorithm can be linear interpolation. Linear interpolation is a method for estimating unknown data points between two known data points. Its basic idea is to assume that the change between data points is linear, that is, they lie on a straight line. The calculation process of linear interpolation is introduced in detail below:

[0059] Suppose there are 4 known data points (x1, y1), (x2, y2), (x3, y4), (x4, y4), where x1 < x2 < x3 < x4.

[0060] When estimating the Y value at the X position (x1 < X < x4), first determine the interval position x of X

[0065] <X < x i+1 . The value of I is 1 or 2 or 3. Furthermore, use the following linear interpolation formula to determine the Y value at the X position:

[0061] .

[0062] Therefore, according to the first calibration position parameter corresponding to the first motor at each calibrated output wavelength, linear interpolation can be performed using the linear interpolation algorithm to fit the output wavelength-first motor position mapping relationship.

[0063] Furthermore, according to the second calibration position parameter corresponding to the second motor at each calibrated output wavelength, quadratic linear interpolation can be performed using the linear interpolation algorithm to fit the output wavelength-second motor position mapping relationship.

[0064] In one possible implementation, the nonlinear frequency conversion element is one of the following: a frequency doubling element, a sum frequency element.

[0065] When the nonlinear frequency conversion element is a frequency doubling element, the repeatability of frequency-doubled light with different target output wavelengths and its highest frequency doubling efficiency can be effectively achieved by using the target optical path.

[0066] Figure 3 A schematic diagram of a target optical path according to an embodiment of the present disclosure is shown. For example... Figure 3 As shown, the laser output from pump source 301 passes through half-wave plate 302, ceramic aperture 303, and reflector 304 before entering the OPO resonant cavity. The OPO resonant cavity consists of OPO oscillator rear mirror 308, beam splitter 305, OPO tuning element 306 (two OPO crystals, for example, two BBO crystals), and OPO output mirror 307. After tuning by the OPO resonant cavity, the signal light and idler light output are separated by signal beam splitter 309. After passing through ceramic aperture 303, the signal light is converted into frequency-doubled light by frequency-doubled element 310 (two frequency-doubled crystals, for example, two BBO crystals), and the frequency-doubled light and signal light are separated by beam splitter 311.

[0067] When the nonlinear frequency conversion element is a sum-frequency element, the repeatability of sum-frequency light with different target output wavelengths and its highest sum-frequency efficiency can be effectively achieved by using the target optical path.

[0068] Figure 4 A schematic diagram of a target optical path according to an embodiment of the present disclosure is shown. For example... Figure 4 As shown, the laser output from pump source 401 passes through half-wave plate 402, ceramic aperture 403, and reflector 404 before entering the OPO resonant cavity. The OPO resonant cavity consists of OPO oscillator rear mirror 408, beam splitter 405, OPO tuning element 406 (two OPO crystals, for example, two BBO crystals), and OPO output mirror 407. After tuning by the OPO resonant cavity, the signal light and idler light output are separated by signal beam splitter 409. The laser output from pump source 412 passes through reflector 413 and half-wave plate 414, and is coaxial with the signal light by beam splitter 415. After passing through ceramic aperture 403, it is converted into sum-frequency light by sum-frequency element 410 (two sum-frequency crystals, for example, two BBO crystals). The sum-frequency light and signal light are separated by beam splitter 411.

[0069] like Figure 3 and Figure 4 As shown, two OPO crystals are respectively mounted on two first voice coil motors, and two frequency doubling / sum frequency crystals are respectively mounted on two second voice coil motors. The four voice coil motors are calibrated to obtain a preset mapping relationship, which allows direct adjustment of the position of the fourth voice coil motor. This effectively simplifies the optical path adjustment process and enables the rapid and accurate acquisition of the target output wavelength and its highest frequency doubling light / highest sum frequency efficiency sum frequency light, thus improving the stability of output performance.

[0070] According to embodiments of this disclosure, based on the desired target output wavelength, a first target position parameter corresponding to the first motor used to control the OPO tuning element at the target output wavelength and a second target position parameter corresponding to the second motor used to control the nonlinear frequency conversion element at the target output wavelength are determined in a preset mapping relationship. Thus, after the first motor is adjusted to the position indicated by the first target position parameter and the second motor is adjusted to the position indicated by the second target position parameter, OPO tuning is performed using the target optical path followed by nonlinear frequency conversion, thereby determining the output light with the target output wavelength. Based on the preset mapping relationship, the first and second motors can be used to synchronously and quickly control the OPO tuning element and the nonlinear frequency conversion element, simplifying the complexity of optical path adjustment. Furthermore, output light with different target output wavelengths can be obtained quickly and accurately, improving the stability of output performance.

[0071] It is understood that the various method embodiments mentioned above in this disclosure can be combined with each other to form combined embodiments without violating the principle and logic. Due to space limitations, this disclosure will not elaborate further. Those skilled in the art will understand that in the above methods of specific implementation, the specific execution order of each step should be determined by its function and possible internal logic.

[0072] In addition, this disclosure also provides an OPO tuned and then nonlinear frequency conversion device. All of the above can be used to implement any of the OPO tuned and then nonlinear frequency conversion methods provided in this disclosure. The corresponding technical solutions and descriptions are described in the corresponding records in the method section and will not be repeated here.

[0073] Figure 5 A block diagram of an apparatus for OPO tuning followed by nonlinear frequency conversion according to an embodiment of the present disclosure is shown. The apparatus is applied to a target optical path, which includes: an OPO tuning element, a nonlinear frequency conversion element, a first motor for controlling the OPO tuning element, and a second motor for controlling the nonlinear frequency conversion element. Figure 5 As shown, the device 50 includes:

[0074] The position parameter determination module 51 is used to determine the first target position parameter of the first motor at the target output wavelength and the second target position parameter of the second motor at the target output wavelength according to the target output wavelength and in a preset mapping relationship.

[0075] The OPO tuning and nonlinear frequency conversion module 52 is used to perform OPO tuning and nonlinear frequency conversion using the target optical path after the first motor is adjusted to the position indicated by the first target position parameter and the second motor is adjusted to the position indicated by the second target position parameter, to determine the output light with the target output wavelength.

[0076] In one possible implementation, the target optical path also includes: a pump source;

[0077] Device 50 also includes:

[0078] The output wavelength range determination module is used to determine the output wavelength range corresponding to the target optical path based on the pump source, OPO tuning element, and nonlinear frequency conversion element.

[0079] The calibration output wavelength determination module is used to determine multiple calibration output wavelengths within the output wavelength range corresponding to the target optical path.

[0080] The calibration module is used to calibrate the first motor and the second motor, and to determine the first calibration position parameter corresponding to the first motor and the second calibration position parameter corresponding to the second motor under each calibration output wavelength.

[0081] The fitting module is used to fit a preset mapping relationship based on the first calibration position parameters of the first motor and the second calibration position parameters of the second motor under each calibration output wavelength.

[0082] In one possible implementation, the calibration module is specifically used for:

[0083] For any given calibrated output wavelength, drive the first motor and the second motor to scan within their respective position ranges, and record the wavelength and energy of the output light of the target optical path under each position combination;

[0084] Based on the position combination corresponding to the output light of the target optical path having the specified output wavelength and the maximum energy, determine the first specified position parameter of the first motor and the second specified position parameter of the second motor under the specified output wavelength.

[0085] In one possible implementation, both the first motor and the second motor are voice coil motors.

[0086] In one possible implementation, the nonlinear frequency conversion element is one of the following: a frequency multiplier element or a frequency summer element.

[0087] In some embodiments, the functions or modules of the apparatus provided in this disclosure can be used to perform the methods described in the above method embodiments. The specific implementation can be referred to the description of the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0088] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0089] Those skilled in the art will understand that, in the above-described method of the specific implementation, the order in which each step is written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic.

[0090] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method of OPO tuning followed by nonlinear frequency conversion, characterized in that, The method is applied to a target optical path, which includes: an OPO tuning element, a nonlinear frequency conversion element, a first motor for controlling the OPO tuning element, and a second motor for controlling the nonlinear frequency conversion element; the method includes: Based on the target output wavelength, in a preset mapping relationship, determine the first target position parameters corresponding to the first motor and the second target position parameters corresponding to the second motor when the nonlinear transformation efficiency is highest at the target output wavelength; After the first motor is adjusted to the position indicated by the first target position parameter and the second motor is adjusted to the position indicated by the second target position parameter, the target optical path is used for OPO tuning and then nonlinear frequency conversion to determine the output light with the target output wavelength and the highest nonlinear conversion efficiency. The target optical path also includes: a pump source; The method further includes: The output wavelength range corresponding to the target optical path is determined based on the pump source, the OPO tuning element, and the nonlinear frequency conversion element. Within the output wavelength range corresponding to the target optical path, multiple calibration output wavelengths are determined; For any given calibrated output wavelength, drive the first motor and the second motor to scan within their respective position ranges, and record the wavelength and energy of the output light of the target optical path under each position combination; Based on the position combination corresponding to the output light of the target optical path having the specified output wavelength and maximum energy, determine the first specified position parameter of the first motor and the second specified position parameter of the second motor under the specified output wavelength. The preset mapping relationship is obtained by fitting the first calibration position parameters corresponding to the first motor and the second calibration position parameters corresponding to the second motor under each calibration output wavelength.

2. The method according to claim 1, characterized in that, Both the first motor and the second motor are voice coil motors.

3. The method according to claim 1, characterized in that, The nonlinear frequency conversion element is one of the following: a frequency multiplier element or a frequency summer element.

4. A device for nonlinear frequency conversion after OPO tuning, characterized in that, The device is applied to a target optical path, which includes: an OPO tuning element, a nonlinear frequency conversion element, a first motor for controlling the OPO tuning element, and a second motor for controlling the nonlinear frequency conversion element; the device includes: The position parameter determination module is used to determine, based on the target output wavelength and within a preset mapping relationship, the first target position parameter corresponding to the first motor and the second target position parameter corresponding to the second motor when the nonlinear transformation efficiency is highest at the target output wavelength. The OPO tuning and nonlinear frequency conversion module is used to perform OPO tuning and nonlinear frequency conversion using the target optical path after the first motor is adjusted to the position indicated by the first target position parameter and the second motor is adjusted to the position indicated by the second target position parameter, in order to determine the output light with the target output wavelength and the highest nonlinear conversion efficiency. The target optical path also includes: a pump source; The device further includes: The output wavelength range determination module is used to determine the output wavelength range corresponding to the target optical path based on the pump source, the OPO tuning element, and the nonlinear frequency conversion element. The calibration output wavelength determination module is used to determine multiple calibration output wavelengths within the output wavelength range corresponding to the target optical path; The calibration module is used to drive the first motor and the second motor to scan within their respective position ranges for any calibration output wavelength, record the wavelength and energy of the output light of the target optical path under each position combination; and determine the first calibration position parameter corresponding to the first motor and the second calibration position parameter corresponding to the second motor under the calibration output wavelength based on the position combination corresponding to the output light of the target optical path having the calibration output wavelength and the maximum energy. The fitting module is used to fit the preset mapping relationship based on the first calibration position parameters corresponding to the first motor and the second calibration position parameters corresponding to the second motor under each calibration output wavelength.

5. The apparatus according to claim 4, characterized in that, Both the first motor and the second motor are voice coil motors.

6. The apparatus according to claim 4, characterized in that, The nonlinear frequency conversion element is one of the following: a frequency multiplier element or a frequency summer element.

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