Summary of the invention
For solving the problem that exists in the background technology; The purpose of the utility model is to provide a kind of MOPA (Maser Oscillator Power Amplifier) system of semiconductor pumped alkali metal vapour laser; This system combines two kinds of live width matching process; Use the holographic grating frequency-selecting that the LDA live width is compressed to tens to tens GHz; And in the gain media pond, charge into buffer gas broadening alkali metal atom and absorb line so far about width, improve both matching degrees, thereby effectively improve pumping efficiency; Use two gain media ponds simultaneously; One is the main oscillations pond; One the laser that the main oscillations pond produces converges at the second polarizing beam splitter mirror place as the pump light of seed light and 4/5 in order to amplify the pond, together incides and amplifies in the pond; Amplify alkali metal vapour laser output that the pond produces and be exactly the laser that has amplified, can the alkali metal vapour laser power be amplified more than the several times.
The utility model solves the technical scheme that its technical problem adopted:
The pump light that semiconductor laser array sends through fast axis collimation mirror, first planoconvex spotlight, the first half slides, second planoconvex spotlight after after holographic grating reflexes to first mirror reflects; Be divided into the two-way pump light through post lens, the 3rd planoconvex spotlight, Siping City's convex lens to beam splitter again; Road pump light behind beam splitter is through first convex lens to the first polarizing beam splitter mirror; Arrive high reflective mirror through the main oscillations pond; The light of high reflective mirror reflection is incident to first polarizing beam splitter mirror once more behind the main oscillations pond; Through output coupling mirror to second speculum, the 3rd speculum, the 4th speculum, second half-wave plate, second convex lens to the second polarizing beam splitter mirror; Light is divided into two-way light after amplifying pond, the 3rd polarizing beam splitter mirror, export light to a road of the 3rd polarizing beam splitter mirror and connect power meter for alkali metal vapour laser, and another road output light is residual pump light; Through another road pump light to the three half-wave plates, the 3rd convex lens of beam splitter, overlapping at second polarizing beam splitter mirror and another road light; At the center of each element on the same straight line on same optical axis.
Described semiconductor laser array front end face is coated with anti-anti-film; And its front end is on the focus of first planoconvex spotlight; The first half slides are simultaneously on the focus of first planoconvex spotlight, second planoconvex spotlight; Holographic grating is on the focus of second planoconvex spotlight, and the fast axis collimation mirror is regulated in experiment apart from the distance of semiconductor laser array front end and confirmed, concentrates with the hot spot edge clear brightness behind the collimation to be as the criterion; The distance of the 3rd planoconvex spotlight and post lens is both focal length sums for both focal length sums, the distance of the 3rd planoconvex spotlight and Siping City's convex lens.
Described main oscillations pond is in the focal length of first convex lens.
Described amplification pond is in the focal length of second convex lens.
Described first speculum is parallel with holographic grating, and second speculum is parallel with the 3rd speculum, and the 3rd speculum is vertical with the 4th speculum.
The useful effect that the utlity model has is:
The semiconductor laser live width compressibility that use is made up of fast axis collimation mirror, first planoconvex spotlight, second planoconvex spotlight and holographic grating; The buffer gas that in main oscillations pond, amplification pond, charges into the optimization atmospheric pressure value of confirming the research back simultaneously absorbs line with the broadening alkali metal atom; Can the LDA live width effectively be compressed to the magnitude of the alkali metal atom line-width behind the broadening, realize the coupling of both live widths.Pump light being pressed the pro rate of 1:4 gives the main oscillations pond and amplifies two gain media ponds, pond; Because two vibration pool structures are identical, ensured beam quality, disperseed heat simultaneously; And can obtain good result experimentally with more than the power amplification several times.
Description of drawings
Accompanying drawing 1 is the index path of the utility model.
Among the figure: 1, semiconductor laser array, 2, the fast axis collimation mirror, 3, first planoconvex lens, 4, first half-wave plate, 5, second planoconvex lens; 6, holographic grating, 7, first speculum, 8, the post lens, the 9, the 3rd planoconvex lens, 10, Siping City's convex lens; 11, beam splitter, 12, first convex lens, 13, first polarizing beam splitter mirror, 14, the main oscillations pond, 15, temperature control box; 16, high reflective mirror, 17, output coupling mirror, 18, second speculum, the 19, the 3rd speculum, the 20, the 4th speculum; 21, second half-wave plate, 22, second convex lens, 23, second polarizing beam splitter mirror, the 24, the 3rd half-wave plate, the 25, the 3rd convex lens; 26, amplify the pond, 27, temperature control box, the 28, the 3rd polarizing beam splitter mirror, 29, residual pump light output, 30, power meter.
Embodiment
Further specify below in conjunction with the execution mode of accompanying drawing the utility model.
Shown in accompanying drawing; The pump light that semiconductor laser array 1 sends through fast axis collimation mirror 2, first planoconvex spotlight 3, the first half slides 4, second planoconvex spotlight 5 after after holographic grating 6 reflexes to 7 reflections of first speculum; Be divided into the two-way pump light through post lens 8, the 3rd planoconvex spotlight 9, Siping City's convex lens 10 to beam splitter 11 again; Road pump light behind beam splitter 11 is through first convex lens, 12 to first polarizing beam splitter mirrors 13; 14 to high reflective mirror 16 through the main oscillations pond; The light of high reflective mirror reflection is incident to first polarizing beam splitter mirror 13 once more behind main oscillations pond 14, through output coupling mirror 17 to second speculums 18, the 3rd speculum 19, the 4th speculum 20, second half-wave plate 21, second convex lens, 22 to second polarizing beam splitter mirrors 23, light is divided into two-way light after amplifying pond 26, the 3rd polarizing beam splitter mirror 28; Road output light (alkali metal vapour laser) to the 3rd polarizing beam splitter mirror connects power meter 30, and another road output light is residual pump light 29; To another road pump light of beam splitter 11, to the 3rd half-wave plate 24, the 3rd convex lens 25, overlapping with another road light behind beam splitter at second polarizing beam splitter mirror 23; At the center of each element on the same straight line on same optical axis.
The MOPA system of the disclosed semiconductor pumped alkali metal vapour laser of the utility model comprises semiconductor laser live width compressibility, seed light system, power amplifying system and beam shaping and coupled system, wherein:
1) semiconductor laser live width compressibility: comprise semiconductor laser array 1, fast axis collimation mirror 2, the first planoconvex spotlights 3, second planoconvex spotlight, 5, the first half slides 4, holographic grating 6.Semiconductor laser array 1 front end face is coated with anti-anti-film; And its front end is on the focus of first planoconvex spotlight 3; On the focus of first planoconvex spotlight 3, second planoconvex spotlight 5, holographic grating 6 is on the focus of second planoconvex spotlight 5 simultaneously for the first half slides 4, and fast axis collimation mirror 2 be a millimeter magnitude apart from the distance of semiconductor laser array front end; Particular location can be regulated in test definite, concentrates with the hot spot edge clear brightness behind the collimation to be as the criterion; The distance of the 3rd planoconvex spotlight 9 and post lens 8 is both focal length sums, and the distance of the 3rd planoconvex spotlight 9 and Siping City's convex lens 10 is both focal length sums.
2) seed light system: comprise first convex lens, 12, the first polarizing beam splitter mirrors 13, main oscillations pond 14, temperature control box 15, high reflective mirror 16, output coupling mirror 17.System is " L " type layout, and main oscillations pond 14 is in the focal length of first convex lens 12.Main oscillations pond 14 is put in the temperature control box 15.
3) power amplifying system: comprise second half-wave plate, 21, the second convex lens, 22, the second polarizing beam splitter mirrors 23, amplify pond 26, temperature control box 27, the 3rd polarizing beam splitter mirror 28, power meter 30, the three half-wave plates 24, the 3rd convex lens 25.Amplifying pond 26 is put in the temperature control box 27.Amplify pond 26 in the focal length of second convex lens 22.
4) beam shaping and coupled system: comprise four total reflective mirrors 7,18,19,20, post lens 8, the three planoconvex spotlights 9, the Siping City's convex lens 10, beam splitter 11.First speculum 7 is parallel with holographic grating 6, and second speculum 18 is parallel with the 3rd speculum 19, and the 3rd speculum 19 is vertical with the 4th speculum 20.
Semiconductor laser live width compressibility: the fast axis collimation mirror is pressed close to the LDA front end place,, accomplish efficiently to utilize pump light with the light that collimation fast axle has promptly been dispersed along optical axis direction; The telescopic system multiplication factor is f
2/ f
1(f wherein
1, f
2Be respectively the focal length of first planoconvex spotlight, second planoconvex spotlight, this multiplication factor that the utility model uses is about 4 times), be used for extensible beam and LDA imaged in holographic grating, for reducing aberration, two lens of telescopic system use planoconvex lens; The first half slides can be regulated feedback, come the excessive damage of anti-feedback power LDA; Through regulating the angle and the gradient of holographic grating, select the centre wavelength of needs, mask its all band, thereby greatly reduce the live width of LDA.Through the angle and the gradient of adjustment holographic grating, make pump light maximum at the central wavelength power of needs, this can record through spectrometer; Rotate half slide then, make pump light that suitable feedback arranged, be about 30% of LDA power.
Pump beam after the live width compression is through the first speculum output parallel with holographic grating; Because the pump light variation aspect collimation and spatial symmetry after the live width compression; So need its shaping, the post lens play collimating effect, the telescopic system that the 3rd planoconvex spotlight, Siping City's convex lens are formed can be converted into the size bigger slightly than main oscillations pond with beam sizes; Thereby make pump light cover main oscillations Chi Chi, further improve pumping efficiency.Get into the beam shaping system, through the adjusting to beam sizes of the collimation and the 3rd of post lens, Siping City's convex lens, pump light is respectively applied for the pumping of amplifying pond and main oscillations pond through the light beam beam splitter in the ratio of power 4:1.
The seed light system: 1/5 pump light is used for pumping main oscillations pond, is about the focusing of first convex lens of 20cm through focal length, crosses first polarizing beam splitter mirror, to the center in main oscillations pond.The main oscillations pond is put in the temperature control box, is filled with gain media in the pond, simultaneously certain buffer gas of optimizing atmospheric pressure value comes the broadening alkali metal atom to absorb line, with the LDA live width coupling of having compressed, thereby realize pumping efficiently.Atomic density in the steam pond is controlled through the temperature of temperature control box, regulates temperature control box, makes vibration pond, pond window temperature higher 5 ℃ than pond temperature, and temperature control is floated and is controlled at 0.1 ℃.Behind the pump light process main oscillations pond; Obtain alkali metal vapour laser, use reflectivity to be about 99.5% high reflective mirror the main oscillations pond is gone back in alkali metal vapour laser-bounce, the laser that polarizing beam splitter mirror is exported pump light and main oscillations pond separates; Because both polarized orthogonals; After alkali metal vapour laser separates with pump light, be the output of 20% output coupling mirror, export this part alkali metal vapour laser and will after coupling, be incident to as seed light and amplify the pond through reflectivity.
Alkali metal vapour laser through output coupling mirror output carries out the adjusting of beam direction through second speculum, the 3rd speculum, the 4th speculum, the ingoing power amplification system.
Power amplifying system: other 4/5 pump light incides the center of amplifying the pond through second polarizing beam splitter mirror after with the 3rd convex lens focus, amplifies the structure in pond and controls with the main oscillations pond with temperature.Seed light incides the center of amplifying the pond through second polarizing beam splitter mirror after second convex lens focus.Rotate second half-wave plate, the 3rd half-wave plate, the incident power that can regulate light beam.Seed light and pump light are overlapping to amplify efficient to improve in order better to make, and amplifies the pond in the focus of second convex lens, moves the position of second convex lens and measures power output simultaneously, and the position of second convex lens was exactly its optimum position when power output was maximum.Amplify output light and remaining pump light after the 3rd polarizing beam splitter mirror behind the pond is used for separating amplification, the alkali metal vapour laser coupled after the amplification is advanced power meter, and residual pump light is exported.