Femtosecond light source system

Abstract

The utility model provides a femtosecond light source system. The femtosecond light source system comprises an optical fiber oscillator, a stretcher, an amplifying mechanism, a compressor, a frequency shifter and a frequency multiplier which are sequentially arranged along a light path, the optical fiber oscillator comprises a first er doped optical fiber; the stretcher broadens the femtosecond pulse light; the amplification mechanism amplifies the broadened femtosecond pulse light; the compressor compresses the amplified femtosecond pulse light; the frequency shifter shifts the frequency of the compressed femtosecond pulse light; and a first filter and a second filter which can be rotatably switched are arranged in the frequency multiplier. According to the femtosecond light source system, femtosecond pulse light is generated through an er-doped gain optical fiber, broadening, amplification, compression, frequency shift and frequency multiplication are conducted on the femtosecond pulse light through a broadening device, an amplification mechanism, a compressor, a frequency shifter and a frequency multiplier, the finally output femtosecond light is not output in a single wavelength mode, and distributed imaging of 740 nm and 810 nm is achieved. The femtosecond light source system uses the optical fiber as the waveguide, so that the use of spatial light is reduced, and the stability of the system is higher.

Description

Technical Field

[0001] The utility model relates to the technical field of lasers, in particular to a femtosecond light source system. Background Art

[0002] The Ti:Sapphire femtosecond laser system mainly consists of two parts: a Ti:Sapphire femtosecond laser oscillator and a femtosecond laser amplifier based on chirped pulse amplification technology. The Ti:Sapphire femtosecond laser oscillator uses titanium sapphire as the gain medium and is a device that produces femtosecond ultrashort pulse lasers based on the Kerr lens mode-locking mechanism. The femtosecond laser amplification system uses chirped pulse amplification technology to amplify the output pulses of the femtosecond laser oscillator. The amplifier includes several parts such as a stretcher, a regenerative amplifier, and a compressor. The femtosecond seed light of the femtosecond mode-locked oscillator undergoes pulse stretching to the picosecond level. After the stretched pulse enters the amplifier, it absorbs the energy stored in the gain medium and then enters the compressor to compress the width of the amplified pulse back to the femtosecond level, thereby obtaining a high-energy optical pulse output.

[0003] For some biological and medical laboratories, the experimental platform area is very valuable, and the existing titanium sapphire laser is too large. In addition, because titanium sapphire lasers are sensitive to temperature and air humidity, they also need to be equipped with coolers, air purification circulation devices, and some laser controllers. Large and complex systems not only take up space, but also have disadvantages such as poor maintainability, high cost, poor output spot quality, and the need for precise dimming. Utility Model Content

[0004] The embodiment of the utility model provides a femtosecond light source system, which solves the shortcomings of the existing titanium sapphire laser, such as large size, poor maintainability, high cost, poor output light spot quality, and the need for precise dimming.

[0005] The present invention provides a femtosecond light source system, comprising:

[0006] A fiber oscillator, a stretcher, an amplifier, a compressor, a frequency shifter and a frequency multiplier are sequentially arranged along the optical path;

[0007] The fiber oscillator includes a first Er-doped fiber for generating femtosecond pulse light; the stretcher is used to stretch the femtosecond pulse light; the amplification mechanism is used to amplify the stretched femtosecond pulse light; the compressor is used to compress the amplified femtosecond pulse light; the frequency shifter is used to shift the frequency of the compressed femtosecond pulse light; the frequency doubler is provided with a first filter and a second filter that can be rotatably switched, which are used to double the frequency of the shifted femtosecond pulse light to achieve distributed imaging of 740nm and 810nm.

[0008] According to a femtosecond light source system provided by an embodiment of the utility model, the amplification mechanism includes: a pre-amplifier, a primary amplifier and a secondary amplifier which are sequentially arranged along the light path.

[0009] According to a femtosecond light source system provided by an embodiment of the present invention, the amplification mechanism further includes: a heat dissipation unit, and at least one of the pre-amplifier, the first-stage amplifier and the second-stage amplifier is arranged on the heat dissipation unit.

[0010] According to a femtosecond light source system provided by an embodiment of the utility model, the pre-amplifier comprises: a first wavelength division multiplexer, a second Er-doped optical fiber and a first polarization-maintaining isolator arranged in sequence along the optical path; the incident end of the first wavelength division multiplexer is aligned with the stretcher;

[0011] The first-stage amplifier comprises: a second wavelength division multiplexer, a third Er-doped optical fiber and a second polarization-maintaining isolator arranged in sequence along the optical path; the incident end of the second wavelength division multiplexer is aligned with the output end of the first polarization-maintaining isolator;

[0012] The secondary amplifier comprises: a beam combiner and an Er-Yb co-doped optical fiber sequentially arranged along an optical path; the incident end of the beam combiner is aligned with the output end of the second polarization-maintaining isolator, and the output end of the Er-Yb co-doped optical fiber is aligned with the compressor.

[0013] According to a femtosecond light source system provided by an embodiment of the utility model, the stretcher includes: a polarization-maintaining dispersion-compensating optical fiber; the polarization-maintaining dispersion-compensating optical fiber is used to stretch the femtosecond pulse light to a picosecond level.

[0014] According to a femtosecond light source system provided by one embodiment of the utility model, the compressor comprises: a first collimator, a polarization beam splitter prism, a compensator and a first half-wave plate arranged in sequence along the optical path;

[0015] The incident end of the first collimator is aligned with the amplifying mechanism, the transmission end of the polarization beam splitter prism is aligned with the compensator, and the reflection end of the polarization beam splitter prism is aligned with the frequency shifter through the first half-wave plate.

[0016] According to a femtosecond light source system provided by one embodiment of the utility model, the compensator comprises: a rotator, a second half-wave plate, a first grating plate, a second grating plate and a reflector arranged in sequence along the optical path;

[0017] The transmission end of the polarization beam splitter prism is aligned with the rotator, and the reflection end of the polarization beam splitter prism is aligned with the frequency shifter through the first half-wave plate.

[0018] According to a femtosecond light source system provided by an embodiment of the utility model, the frequency shifter comprises: a second collimator, a nonlinear optical fiber and a third collimator arranged in sequence along the optical path;

[0019] The incident end of the second collimator is aligned with the compressor, and the output end of the third collimator is aligned with the frequency doubler.

[0020] According to a femtosecond light source system provided by one embodiment of the utility model, the frequency doubler includes: a focusing lens, a frequency doubling crystal, a collimating lens and a fourth collimator arranged in sequence along the optical path; the incident end of the focusing lens is aligned with the frequency shifter through the first filter, and the second filter is arranged between the collimating lens and the fourth collimator.

[0021] According to a femtosecond light source system provided by an embodiment of the utility model, the frequency doubler further includes: a quarter glass slide and a half glass slide; the quarter glass slide and the half glass slide are sequentially arranged between the first filter and the focusing lens.

[0022] The femtosecond light source system provided by the utility model is provided with an optical fiber oscillator, a stretcher, an amplifying mechanism, a compressor, a frequency shifter and a frequency multiplier arranged in sequence along the optical path, and uses an Er-doped gain optical fiber to generate femtosecond pulse light, and uses a stretcher, an amplifying mechanism, a compressor, a frequency shifter and a frequency multiplier to sequentially stretch, amplify, compress, shift and multiply the femtosecond pulse light, so that the final output femtosecond light is no longer a single wavelength output, and distributed imaging of 740nm and 810nm is achieved by using distributed space-time coupling technology. Compared with titanium sapphire lasers, the femtosecond light source system uses optical fiber as a waveguide, reduces the use of spatial light, has higher system stability, and improves the quality of the output light beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a light path diagram of a femtosecond light source system provided by an embodiment of the utility model;

[0025] Figure 2 is the frequency-shifted spectrum of the femtosecond light source system provided by an embodiment of the utility model;

[0026] Figure 3 is a schematic diagram of a femtosecond light source system provided by an embodiment of the utility model;

[0027] Figure 4 It is a schematic diagram of a heat dissipation unit provided in one embodiment of the utility model;

[0028] Figure 5 is a schematic diagram of a compressor provided by an embodiment of the utility model;

[0029] Figure 6 is a schematic diagram of a frequency multiplier provided by an embodiment of the utility model;

[0030] Reference numerals:

[0031] Among them, 100, fiber oscillator; 200, stretcher; 300, pre-amplifier; 400, primary amplifier; 500, secondary amplifier; 600, compressor; 700, frequency shifter; 800, frequency multiplier; 900, amplification mechanism; 1, first Er-doped fiber; 2, polarization-maintaining dispersion compensation fiber; 3, first wavelength division multiplexer; 4, second Er-doped fiber; 5, first polarization-maintaining isolator; 6, second wavelength division multiplexer; 7, third Er-doped fiber; 8, second polarization-maintaining isolator; 9, combiner; 10, Er-ytterbium Co-doped optical fiber; 11. first collimator; 12. polarization beam splitter; 13. rotator; 14. second half-wave plate; 15. first grating; 16. second grating; 17. reflector; 18. first half-wave plate; 19. second collimator; 20. nonlinear optical fiber; 21. third collimator; 22. first filter; 23. quarter glass; 24. half glass; 25. focusing lens; 26. frequency doubling crystal; 27. collimating lens; 28. second filter; 29. ​​fourth collimator. DETAILED DESCRIPTION

[0032] The following is a further detailed description of the implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0033] In the description of the embodiments of the present invention, the terms “first” and “second” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0034] In the description of the embodiments of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present utility model can be understood according to specific circumstances.

[0035] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model embodiment. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0036] The utility model provides a femtosecond light source system, such as Figures 1 to 3 As shown, the femtosecond light source system includes: a fiber oscillator 100, a stretcher 200, an amplification mechanism 900, a compressor 600, a frequency shifter 700 and a frequency multiplier 800 arranged in sequence along the optical path. The entire femtosecond light source system adopts a modular design, which makes the structure of the entire system compact, more stable and more maintainable.

[0037] Among them, the fiber oscillator 100 includes a first erbium-doped fiber 1 for generating femtosecond pulse light. The stretcher 200 is used to stretch the femtosecond pulse light, using the technical means of chirped pulse amplification, and using the polarization-maintaining dispersion compensation fiber 2 to stretch the seed light. The amplification mechanism 900 is used to amplify the stretched femtosecond pulse light, using a single-mode erbium-doped gain fiber for pre-amplification and primary amplification, and using a double-clad erbium co-doped fiber for secondary amplification, and the output power can reach up to about 3W. The compressor 600 is used to compress the amplified femtosecond pulse light, using a grating pair with high diffraction efficiency for dispersion compensation, and by adjusting the grating spacing, the anomalous dispersion introduced by the grating pair effectively compensates for the normal dispersion introduced by the stretcher 200. After amplification and compression, a femtosecond light of about 1.5W and 800fs in the 1560nm band is obtained. The frequency shifter 700 is used to shift the frequency of the compressed femtosecond pulse light, that is, to generate the accumulation of nonlinear phase in the propagation of the optical fiber, so that the pulse generates frequency chirp, and the corresponding pulse spectrum is broadened. In addition, the 1560nm femtosecond light spectrum can be broadened to 1480nm on the left and 1620nm on the right. The frequency multiplier 800 is provided with a first filter 22 and a second filter 28 that can be rotatably switched, which are used to double the frequency of the shifted femtosecond pulse light. After the frequency shift, 1480nm and 1620nm optical pulses are obtained, and after passing through the frequency multiplier 800, 740nm and 810nm doubled frequency light are generated.

[0038] Specifically, the fiber oscillator 100 adopts the mode-locking mechanism of the nonlinear loop reflector and uses the first erbium-doped fiber 1 as the gain medium to generate femtosecond pulse light in the 1560nm band. The polarization-maintaining dispersion-compensating fiber 2 in the stretcher 200 is used to stretch the femtosecond pulse light to the picosecond level to reduce the impact of excessive peak power and nonlinearity in the subsequent amplification process. The amplification mechanism 900 is used to amplify the stretched femtosecond pulse light. The compressor 600 is used to compress the amplified femtosecond pulse light. After amplification and compression, a femtosecond pulse light in the 1560nm band of about 1.5W and 800fs can be obtained. The frequency shifter 700 is used to shift the frequency of the compressed femtosecond pulse light, such as Figure 2 As shown, Figure 2 The spectrum is output after frequency shifting, and the spectrum is widened to 1480nm on the left and 1620nm on the right by using the self-phase modulation effect. The frequency doubler 800 is used to double the frequency of the femtosecond pulse light after frequency shifting, and the first filter 22 and the second filter 28 rotate synchronously or asynchronously to obtain light at 740nm and 810nm, and then the femtosecond pulse light is output, realizing distributed imaging of 740nm and 810nm.

[0039] The femtosecond light source system provided by the utility model is provided with an optical fiber oscillator, a stretcher, an amplifying mechanism, a compressor, a frequency shifter and a frequency multiplier arranged in sequence along the optical path, and uses an Er-doped gain optical fiber to generate femtosecond pulse light, and uses a stretcher, an amplifying mechanism, a compressor, a frequency shifter and a frequency multiplier to sequentially stretch, amplify, compress, shift and multiply the femtosecond pulse light, so that the final output femtosecond light is no longer a single wavelength output, and distributed imaging of 740nm and 810nm is achieved by using distributed space-time coupling technology. Compared with titanium sapphire lasers, the femtosecond light source system uses optical fiber as a waveguide, reduces the use of spatial light, has higher system stability, and improves the quality of the output light beam.

[0040] In addition, according to user needs, Er-doped fiber is also used as the gain medium to obtain 1560nm femtosecond pulse light, which is then amplified using a frequency-doubling crystal to obtain femtosecond light in the 780nm band. The frequency is then shifted using a nonlinear fiber suitable for 780nm to obtain femtosecond light in the 740nm / 810nm band.

[0041] In one embodiment provided by the present utility model, Figure 1 As shown, the amplification mechanism includes: a pre-amplifier 300, a primary amplifier 400 and a secondary amplifier 500 which are sequentially arranged along the optical path.

[0042] In this embodiment, the preamplifier 300 includes: a first wavelength division multiplexer 3, a second Er-doped fiber 4 and a first polarization-maintaining isolator 5 arranged in sequence along the optical path, and the first wavelength division multiplexer 3, the second Er-doped fiber 4 and the first polarization-maintaining isolator 5 are connected in sequence by fusion splicing. The incident end of the first wavelength division multiplexer 3 is aligned with the stretcher, that is, the incident end of the first wavelength division multiplexer 3 is aligned with the polarization-maintaining dispersion compensation fiber 2, for receiving the stretched femtosecond pulse light.

[0043] During the operation of the femtosecond light source system, the femtosecond pulse light (signal light) after being broadened by the broadener passes through the first wavelength division multiplexer 3 and enters the single-mode second Er-doped optical fiber 4 for pre-amplification, and then passes through the first polarization-maintaining isolator 5, thereby avoiding the problem of low power output of the light beam due to the power being too low after broadening and the subsequent power amplification efficiency being low.

[0044] In this embodiment, the first-stage amplifier 400 includes: a second wavelength division multiplexer 6, a third Er-doped fiber 7, and a second polarization-maintaining isolator 8, which are sequentially arranged along the optical path. The second wavelength division multiplexer 6, the third Er-doped fiber 7, and the second polarization-maintaining isolator 8 are sequentially connected by fusion. The incident end of the second wavelength division multiplexer 6 is aligned with the output end of the first polarization-maintaining isolator 5, that is, the second wavelength division multiplexer is used to receive the femtosecond pulse light after being pre-amplified by the second Er-doped fiber 4.

[0045] During the operation of the femtosecond light source system, the pre-amplified femtosecond pulse light passes through the second wavelength division multiplexer 6 and enters the single-mode third Er-doped optical fiber 7 for primary amplification, and then passes through the second polarization-maintaining isolator 8. The primary amplified femtosecond pulse light can reach hundreds of milliwatts.

[0046] In this embodiment, the secondary amplifier 500 includes: a beam combiner 9 and an Er-Yb co-doped optical fiber 10 arranged in sequence along the optical path, and the beam combiner 9 and the Er-Yb co-doped optical fiber 10 are connected by fusion. The incident end of the beam combiner 9 is aligned with the output end of the second polarization-maintaining isolator 8, and the output end of the Er-Yb co-doped optical fiber 10 is aligned with the compressor 600, that is, the beam combiner 9 is used to receive the femtosecond pulse light after the first stage of amplification, and the Er-Yb co-doped optical fiber 10 is used to output the femtosecond pulse light after further amplification.

[0047] During the operation of the femtosecond light source system, the femtosecond pulse light after primary amplification passes through the beam combiner 9 and enters the Er-Yb co-doped optical fiber 10 for secondary amplification. After the secondary amplification, the pulse can be amplified to about 3W.

[0048] A large amount of heat will be generated during the amplification process of the amplification mechanism 900. In order to reduce the heat, Figure 3 and Figure 4As shown, the amplification mechanism 900 further includes a heat dissipation unit 901, on which at least one of the preamplifier 300, the first-stage amplifier 400 and the second-stage amplifier 500 is disposed. That is, the preamplifier 300, the first-stage amplifier 400 and the second-stage amplifier 500 can all be disposed.

[0049] In this embodiment, starting from the beam combiner, the signal light is amplified in the second stage through the double-clad optical fiber. The entire amplification process is carried out under the action of high-power pump light, and the double-clad optical fiber will generate a large amount of heat. At this time, the heat dissipation unit 901 adopts the structure of a heat dissipation plate, and the Er-Yb co-doped optical fiber 10 is wound around the threaded wire on the heat dissipation plate made of aluminum alloy in circles, thereby increasing the area of ​​optical fiber heat dissipation or increasing fan convection, thereby accelerating the heat dissipation of the entire process and ensuring the stability of the system.

[0050] In addition, according to user needs, the second Er-doped fiber 4 in the preamplifier 300 can be wound on the heat sink, or the third Er-doped fiber 7 of the first-stage amplifier 400 can be wound on the heat sink to accelerate the heat dissipation of the preamplifier 300 or the first-stage amplifier 400.

[0051] Based on the above embodiments, in one embodiment provided by the present utility model, as Figure 1 and Figure 5 As shown, the compressor 600 includes: a first collimator 11, a polarization beam splitter prism 12, a compensator and a first half-wave plate 18 arranged in sequence along the optical path; the incident end of the first collimator 11 is aligned with the amplification mechanism 900, the transmission end of the polarization beam splitter prism 12 is aligned with the compensator, and the reflection end of the polarization beam splitter prism 12 is aligned with the frequency shifter 700 through the first half-wave plate 18. The light after secondary amplification is converted into spatial light output through the first collimator 11, and then passes through the compensator after being transmitted through the polarization beam splitter prism 12, and then enters the frequency shifter 700 through the first half-wave plate 18 after being reflected by the polarization beam splitter prism 12, and after amplification and compression, a femtosecond pulse light of about 1.5w and 800fs in the 1560nm band is obtained.

[0052] The compensator includes: a rotator 13, a second half-wave plate 14, a first grating plate 15, a second grating plate 16 and a reflector 17 arranged in sequence along the optical path; the transmission end of the polarization beam splitter prism 12 is aligned with the rotator 13, and the reflection end of the polarization beam splitter prism 12 is aligned with the frequency shifter 700 through the first half-wave plate 18. After the polarization beam splitter prism 12 is folded back, the polarization state entering the frequency-shifting optical fiber can be adjusted by adjusting the first half-wave plate 18 using the magneto-optical effect.

[0053] Specifically, during the operation of the femtosecond light source system, the light after secondary amplification is converted into spatial light output by the first collimator 11, and after being transmitted through the polarization beam splitter prism 12, it passes through the rotator 13 and the second half-wave plate 14, and then is incident on the first grating plate 15 at the best angle for diffraction. The diffracted light is incident on the second grating plate 16 and diffracts again, and then is incident on the reflector 17, and is diffracted by the second grating plate 16 and the first grating plate 15 in turn through the reflector 17. By adjusting the grating spacing, the anomalous dispersion introduced by the grating pair effectively compensates the normal dispersion introduced by the stretcher. The supplemented light beam adjusts the polarization state of the light beam through the second half-wave plate 14, so that after passing through the rotator 13, the light beam is reflected by the polarization beam splitter prism 12 and no longer returns to the initial light path. The first half-wave plate 18 is used to adjust the polarization state of the light beam before entering the non-biased frequency-shifted optical fiber. After amplification and compression, a femtosecond pulse light of 1.5w and about 800fs in the 1560nm band is obtained.

[0054] Based on the above embodiments, in one embodiment provided by the present utility model, as Figure 1 As shown, the frequency shifter 700 includes: a second collimator 19, a nonlinear optical fiber 20 and a third collimator 21 which are sequentially arranged along the optical path, and the second collimator 19, the nonlinear optical fiber 20 and the third collimator 21 are sequentially fused. The incident end of the second collimator 19 is aligned with the compressor 600, and the output end of the third collimator 21 is aligned with the frequency multiplier, that is, the second collimator 19 is used to receive the compressed femtosecond pulse light, and the third collimator 21 is used to collimate the output.

[0055] During the operation of the femtosecond light source system, the second collimator 19 couples the spatial light in the compression process into the nonlinear optical fiber 20, and uses the self-phase modulation effect to broaden the spectrum to 1480nm on the left and 1620nm on the right. The nonlinear optical fiber 20 is collimated and output through the third collimator 21 for subsequent frequency doubling.

[0056] Based on the above embodiments, in one embodiment provided by the present utility model, as Figure 1 and Figure 6 As shown, the frequency multiplier 800 includes: a focusing lens 25, a frequency doubling crystal 26, a collimating lens 27 and a fourth collimator 29 arranged in sequence along the optical path. The incident end of the focusing lens 25 is aligned with the frequency shifter 700 through the first filter 22, and the fourth collimator 29 is directly used to output femtosecond light, thereby realizing distributed imaging of 740nm and 810nm. The second filter 28 is arranged between the collimating lens 27 and the fourth collimator 29.

[0057] The frequency doubler 800 further includes: a quarter glass slide 23 and a half glass slide 24. The quarter glass slide 23 and the half glass slide 24 are sequentially arranged between the first filter 22 and the focusing lens 25. The modular and miniaturized design of the entire frequency doubler 800 makes the frequency doubler 800 compact and can perform a frequency doubling experiment without affecting the stability of the overall optical path, and finally obtain light with wavelengths of 740nm and 810nm.

[0058] Specifically, during the operation of the femtosecond light source system, the first filter 22 and the second filter 28 are rotated and switched. The first filter 22 is used to obtain light at 1480nm and 1620nm, and the fundamental frequency light is made to reach the optimal polarization state through the quarter glass 23 and the half glass 24, and then is focused by the focusing lens 25 to the center position of the frequency doubling crystal 26 to generate 740nm and 810nm double frequency light. Then, it is collimated by the collimating lens 27, and the second filter 28 is used to obtain clean light at 740nm and 810nm, and then the spatial light output is converted into optical fiber output through the fourth collimator 29.

[0059] In summary, compared with titanium sapphire lasers, the femtosecond light source system provided by the utility model uses optical fiber as a waveguide, reduces the use of spatial light, has higher system stability, and improves the quality of the output beam of the fiber laser; in addition, the use of doped optical fiber as a gain medium for light amplification also expands the heat dissipation area of ​​the gain medium. Generally, air cooling combined with some heat sinks can effectively dissipate heat; in addition, the volume of the fiber laser can be miniaturized, and it is very convenient to integrate into some miniaturized microscopic imaging systems. Finally, the obtained fiber femtosecond laser is no longer a single wavelength output, and distributed imaging of 740nm and 810nm is realized.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

[0061] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Although the present invention is described in detail with reference to the embodiments, a person skilled in the art should understand that various combinations, modifications or equivalent substitutions of the technical solutions of the present invention do not deviate from the spirit and scope of the technical solutions of the present invention, and should be included in the scope of the claims of the present invention.

Claims

1. A femtosecond light source system, characterized in that: include: A fiber oscillator, a stretcher, an amplifier, a compressor, a frequency shifter and a frequency multiplier are sequentially arranged along the optical path; The fiber oscillator comprises a first Er-doped fiber, which is used to generate femtosecond pulse light; The stretcher is used to stretch the femtosecond pulse light; The amplification mechanism is used to amplify the broadened femtosecond pulse light; The compressor is used to compress the amplified femtosecond pulse light; The frequency shifter is used to shift the frequency of the compressed femtosecond pulse light; the frequency doubler is provided with a first filter and a second filter that can be rotatably switched, which are used to double the frequency of the femtosecond pulse light after frequency shifting, so as to realize distributed imaging of 740nm and 810nm.

2. The femtosecond light source system according to claim 1, characterized in that: The amplification mechanism comprises: a pre-amplifier, a primary amplifier and a secondary amplifier which are arranged in sequence along the optical path.

3. The femtosecond light source system according to claim 2, characterized in that: The amplification mechanism further includes: a heat dissipation unit, and at least one of the pre-amplifier, the first-stage amplifier and the second-stage amplifier is arranged on the heat dissipation unit.

4. The femtosecond light source system according to claim 2, characterized in that: The pre-amplifier comprises: a first wavelength division multiplexer, a second Er-doped optical fiber and a first polarization-maintaining isolator arranged in sequence along the optical path; the incident end of the first wavelength division multiplexer is aligned with the stretcher; The first-stage amplifier comprises: a second wavelength division multiplexer, a third Er-doped optical fiber and a second polarization-maintaining isolator arranged in sequence along the optical path; the incident end of the second wavelength division multiplexer is aligned with the output end of the first polarization-maintaining isolator; The secondary amplifier comprises: a beam combiner and an Er-Yb co-doped optical fiber sequentially arranged along an optical path; the incident end of the beam combiner is aligned with the output end of the second polarization-maintaining isolator, and the output end of the Er-Yb co-doped optical fiber is aligned with the compressor.

5. The femtosecond light source system according to claim 1, characterized in that: The stretcher comprises: a polarization-maintaining dispersion-compensating optical fiber; the polarization-maintaining dispersion-compensating optical fiber is used to stretch the femtosecond pulse light to the picosecond level.

6. The femtosecond light source system according to any one of claims 1 to 5, characterized in that: The compressor comprises: a first collimator, a polarization beam splitter prism, a compensator and a first half-wave plate arranged in sequence along the optical path; The incident end of the first collimator is aligned with the amplifying mechanism, the transmission end of the polarization beam splitter prism is aligned with the compensator, and the reflection end of the polarization beam splitter prism is aligned with the frequency shifter through the first half-wave plate.

7. The femtosecond light source system according to claim 6, characterized in that: The compensator comprises: a rotator, a second half-wave plate, a first grating plate, a second grating plate and a reflector which are sequentially arranged along the optical path; The transmission end of the polarization beam splitter prism is aligned with the rotator, and the reflection end of the polarization beam splitter prism is aligned with the frequency shifter through the first half-wave plate.

8. The femtosecond light source system according to any one of claims 1 to 5, characterized in that: The frequency shifter comprises: a second collimator, a nonlinear optical fiber and a third collimator which are sequentially arranged along the optical path; The incident end of the second collimator is aligned with the compressor, and the output end of the third collimator is aligned with the frequency doubler.

9. The femtosecond light source system according to any one of claims 1 to 5, characterized in that: The frequency doubler comprises: a focusing lens, a frequency doubling crystal, a collimating lens and a fourth collimator arranged in sequence along the optical path; the incident end of the focusing lens is aligned with the frequency shifter through the first filter, and the second filter is arranged between the collimating lens and the fourth collimator.

10. The femtosecond light source system according to claim 9, characterized in that: The frequency multiplier further includes: a quarter glass slide and a half glass slide; the quarter glass slide and the half glass slide are sequentially arranged between the first filter and the focusing lens.

Images