Tapered laser gain module, tapered laser amplifier and tapered laser oscillator

Abstract

A conical laser gain module comprises a pump light source, a laser rod and a conical structure. A tapered structure including a large taper hole and a small taper hole connected by a taper axis is used to receive a laser rod parallel to the taper axis and concentrate pump light toward the laser rod. Pump light enters the conical structure from the large conical hole to the small conical hole. The laser rod is used for absorbing the pump light so as to generate amplified laser along a laser emission axis parallel to a laser rod axis. Specifically, some of the pump light, which diverges and initially miss the laser rod, is reflected by the inner surface of the tapered structure and concentrated on the laser rod. A tapered laser amplifier and a tapered laser oscillator using a single or tandem tapered laser gain module are also provided.

Description

Technical Field

[0001] The invention relates to a tapered laser gain module, a tapered laser amplifier and a tapered laser oscillator. Background Art

[0002] Lasers produce a collimated beam of radiation with high spectral purity. Laser oscillators usually consist of a laser gain module with a laser bar mounted between two cavity mirrors, one of which is highly reflective for the laser wavelength and the other of which is partially reflective for the laser wavelength. In this configuration, both ends of the laser bar are usually coated with an anti-reflective dielectric layer to reduce optical losses during the laser build-up. The partially reflecting mirror is the so-called output coupler, which emits the laser output. It is also possible to coat one end of the laser bar with a highly reflective dielectric layer and the other end of the laser bar with a partially reflecting layer without using a cavity mirror to form a monolithic laser cavity laser with laser light emitted from the partially reflecting end of the laser bar.

[0003] When a laser gain block has high gain, it can be used to build a laser amplifier by using it with a low-power laser as a seed. In some designs, the seed laser propagates back and forth several times in the laser bar to extract more gain before emitting from the output of the laser gain block. In this multi-channel configuration, the emitting end of the laser bar is also coated with an anti-reflection dielectric layer at the laser wavelength to reduce reflection losses at the air-crystal interface and maximize the amplification gain.

[0004] Generally speaking, laser rod pumping energy must be provided to generate or amplify lasing. Optical pumping is a popular scheme in which, for example, a diode laser of a first wavelength is focused into a small volume that matches the lasing volume in the laser gain medium to efficiently stimulate lasing radiation and generate lasing of another wavelength.

[0005] However, light-emitting diodes (LEDs) or sometimes laser diodes (LDs) emit highly divergent light that is difficult to focus into a small volume to pump a laser rod. In addition, the emission area of ​​a high-power LED light source is usually much larger than that of a laser. Due to the huge mismatch in emission area or volume, the efficiency of converting LED light into laser radiation is usually low. The present invention is to overcome this drawback. Summary of the invention

[0006] The present invention provides a tapered laser gain module, a double-side pumped tapered laser gain module, a tapered laser amplifier and a tapered laser oscillator, which adopt one or more tapered internal reflection structures, each of which includes a laser rod along the cone axis direction to receive artificial pump light for laser amplification and oscillation.

[0007] One embodiment of the present invention provides a tapered laser gain module, which includes an artificial pump light source, a laser rod, and a tapered structure. The pump light source is used to emit a plurality of pump lights along the laser emission axis. The laser rod, whose long axis is parallel to the laser emission axis, is arranged on the power flow path of the pump light and is used to absorb the pump light to generate a plurality of amplified lasers of another wavelength along the laser emission axis. The tapered structure is used to accommodate the laser rod and to confine the pump light toward the laser rod. The tapered axis of the tapered structure is aligned parallel to the laser emission axis. The tapered structure has a large tapered hole and a small tapered hole connected by the tapered axis. The pump light enters the tapered structure from the larger tapered hole to the smaller tapered hole. The pump light, some of which diverges and initially misses the laser rod, is reflected by the inner surface of the tapered structure and concentrated on the laser rod.

[0008] An embodiment of the present invention provides a tapered laser amplifier, which includes the tapered laser gain module and a seed laser. The seed laser is used to inject seed light into the tapered laser gain module for amplification.

[0009] An embodiment of the present invention provides a tapered laser oscillator, which includes the tapered laser gain module, a cavity mirror, and an output coupling mirror. The tapered laser gain module is installed between the cavity mirror and the output coupling mirror. Laser is emitted from the output coupling mirror.

[0010] One embodiment of the present invention provides a double-side pumped tapered laser gain module, which includes two tapered structures, a laser rod, and two artificial pump light sources. The two pump light sources are used to emit a plurality of pump lights of a first wavelength along a laser emission axis. The laser rod is disposed on a power flow path of the pump light and is used to absorb the pump light to generate a plurality of amplified lasers of another wavelength. The long axis of the laser rod is aligned with the laser emission axis. Two tapered structures having a collinear tapered axis connecting two smaller tapered holes are used to accommodate the laser rods and to confine the pump light toward the laser rods. The collinear tapered axes of the tapered structures are aligned parallel to the laser emission axis. The pump light emitted from the two pump light sources enters the two tapered structures from the two larger tapered holes toward the connected smaller tapered holes. The pump light, some of which diverges and initially misses the laser rods, is reflected by multiple inner surfaces of the two tapered structures and concentrated on the laser rods.

[0011] An embodiment of the present invention provides a tapered laser amplifier, which includes the aforementioned double-side pumped tapered laser gain module and a seed laser. The seed laser is used to inject seed light into the double-side pumped tapered laser gain module for amplification.

[0012] An embodiment of the present invention provides a tapered laser oscillator, which includes the aforementioned double-side pumped tapered laser gain module, a cavity mirror, and an output coupling mirror. The double-side pumped tapered laser gain module is installed between the cavity mirror and the output coupling mirror. Laser is emitted from the output coupling mirror.

[0013] The end-pumped conical structure used in the embodiment is particularly effective for converging artificial divergent pump light toward the laser rod. In addition, when the off-axis pump light meanders toward the narrow end of the conical structure, the incident angle of the pump light on the conical surface gradually becomes smaller, and some unabsorbed pump light can be reflected back to re-pump the laser rod. With the single-cone and double-cone structures disclosed in the present invention, artificial divergent pump light sources can still be effectively used for laser pumping. In order to improve laser gain, the present invention further discloses an embodiment of the combination of end pumping and side pumping of the conical laser gain module.

[0014] In order to make the above-mentioned embodiments of the present invention easier to understand, the embodiments of the present invention are further described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The accompanying drawings illustrate exemplary embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure.

[0016] Figure 1A and Figure 1B is a schematic diagram of two different types of tapered laser amplifiers according to an embodiment of the present invention;

[0017] Figure 2A and Figure 2B is a schematic diagram of two different types of tapered laser oscillators according to an embodiment of the present invention;

[0018] Figure 3 is a schematic diagram of a single-taper laser gain module according to a first embodiment of the present invention;

[0019] Figure 4 is a schematic diagram of a single-cone laser gain module with a fluorescent material according to a second embodiment of the present invention;

[0020] Figure 5A is a schematic diagram of a single-taper laser gain module with a cooling water chamber according to a third embodiment of the present invention;

[0021] Figure 5B yes Figure 5A sectional view of

[0022] Fig. 6A is a schematic diagram of a single-taper laser gain module with a cooling water pipe according to a fourth embodiment of the present invention;

[0023] Figure 6B yes Fig. 6A sectional view of

[0024] Fig. 7Ais a schematic diagram of a single-taper laser gain module with end pumping and side pumping according to a fifth embodiment of the present invention;

[0025] Figure 7B yes Fig. 7A sectional view of

[0026] Fig. 8A is a schematic diagram of a double-tapered laser gain module according to a sixth embodiment of the present invention;

[0027] Figure 8B yes Fig. 8A A left cross-sectional view of the pump light source 100-1;

[0028] Figure 8C yes Fig. 8A A right cross-sectional view of the assembly of the pump light source 100-2 and the heat sink / cooling plate 200-2;

[0029] Fig.9A is a schematic diagram of a single-part tapered laser gain module according to a seventh embodiment of the present invention;

[0030] Fig. 9B yes Fig.9A Right section view of

[0031] Fig.10 is a schematic diagram of a double-part tapered laser gain module according to an eighth embodiment of the present invention;

[0032] Fig.11A is a schematic diagram of a partially tapered laser gain module with end pumping and side pumping according to a ninth embodiment of the present invention;

[0033] Fig. 11B yes Fig.11A Right section view of . DETAILED DESCRIPTION

[0034] Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0035] Figure 1A and Figure 1B is a schematic diagram of two different types of tapered laser amplifiers according to an embodiment of the present invention. Figure 1AThe tapered laser amplifier 10 of the present embodiment includes a tapered laser gain module 20 / 20A / 20B / 20C / 20D / 20E / 20H / 20I / 20J and a seed laser 11. The seed laser 11 is used to inject seed light SE into the tapered laser gain module 20 / 20A / 20B / 20C / 20D / 20E / 20H / 20I / 20J. The seed light SE can be a small laser signal that propagates through the laser gain module once or multiple times to extract the laser gain in the laser rod. Preferably, the laser rod (e.g. Figure 3 The surfaces of both ends of the laser rod 300 are plated with anti-reflection dielectric layers 12 and 13 at the wavelength of the seed light to minimize the reflection loss when the seed light SE enters the laser rod.

[0036] Please refer to Figure 1B The tapered laser amplifier 10A of this embodiment is Figure 1A The tapered laser amplifier 10A is similar to the tapered laser amplifier 10, except that the tapered laser amplifier 10A further includes a polarization beam splitter 14A and a quarter wave plate 15A. Preferably, one end surface of the laser rod in the tapered laser gain module 20 / 20A / 20B / 20C / 20D / 20E / 20H / 20I / 20J is coated with an anti-reflection dielectric layer 12A to minimize the reflection loss of the seed light SE entering the laser rod, and the other end surface of the laser rod is coated with a high-reflection dielectric layer 13A at the wavelength of the seed light to reflect the seed light so that the seed light enters the laser rod again for further amplification. In addition, the seed light SE is preferably linearly polarized light. For example, when the input seed light is p-polarized, the seed light SE passes through the polarization beam splitter 14A and then passes to the quarter wave plate 15A. The quarter wave plate 15A converts the p-polarized seed light SE into circularly polarized light, which then enters the tapered laser gain module 20 / 20A / 20B / 20C / 20D / 20E / 20H / 20I / 20J and is reflected from the downstream high reflective medium layer 13A to complete dual-channel amplification. The amplified laser AL is emitted from the front end of the tapered laser gain module 20 / 20A / 20B / 20C / 20D / 20E / 20H / 20I / 20J and passes through the quarter wave plate 15A again to become an s-polarized wave. The amplified laser AL with s-polarization is deflected by the polarization beam splitter 14A and separated from the seed laser path.

[0037] Figure 2A and Figure 2B is a schematic diagram of two different types of tapered laser oscillators according to an embodiment of the present invention. Figure 2AThe tapered laser oscillator 10' of the present embodiment includes a tapered laser gain module 20 / 20A / 20B / 20C / 20D / 20E / 20H / 20I / 20J, a first (highly reflective) cavity mirror 16' and a second cavity mirror (partially reflective output coupling mirror) 17', wherein the tapered laser gain module 20 / 20A / 20B / 20C / 20D / 20E / 20H / 20I / 20J is installed between the first cavity mirror 16' and the second cavity mirror 17'. The tapered laser gain module 20 / 20A / 20B / 20C / 20D / 20E / 20H / 20I / 20J can provide amplification gain for the small signal laser propagating back and forth between the two mirrors. Preferably, the cavity mirror is coated with a highly reflective dielectric layer to reflect the oscillating laser, and the output coupling mirror is coated with a partially reflective dielectric layer to emit the laser.

[0038] Specifically, in the present embodiment, the first cavity mirror 16' is disposed on one side of the tapered laser gain module 20 / 20A / 20B / 20C / 20D / 20E / 20H / 20I / 20J to completely reflect the amplified laser AL. The second cavity mirror 17' is disposed on the other side of the tapered laser gain module 20 / 20A / 20B / 20C / 20D / 20E / 20H / 20I / 20J to partially transmit the laser to output the amplified laser AL. In other words, the first cavity mirror 16' is a high reflective mirror, and the second cavity mirror 17' is a laser output coupler that partially transmits at the laser emission wavelength. In fact, the positions of the first cavity mirror 16' and the second cavity mirror 17' can be interchanged, and the performance of the laser will not be changed except that the laser emission direction is opposite. For example, in order to realize a Nd:YAG laser that is end-pumped by 808nm light and emits at 1064nm, the first cavity mirror 16' and the second cavity mirror 17' are designed to be highly reflective and partially reflective at 1064nm, respectively; the dielectric layers 12 and 13 on the laser rod are designed to be anti-reflective at 1064nm. Preferably, the dielectric layer facing the pump light is anti-reflective at 808nm.

[0039] Please refer to Figure 2B The tapered laser oscillator 10A' of this embodiment is Figure 2A The tapered laser oscillator 10' of the present invention is similar to the tapered laser oscillator 10' of the present invention, but the difference is that the surfaces of both ends of the laser rod in the tapered laser gain module 20 / 20A / 20B / 20C / 20D / 20E / 20H / 20I / 20J are coated with a high-reflection dielectric layer 12A' and a partially-reflective dielectric layer 13A' at the laser wavelength. That is, without using a cavity mirror, the high-reflection dielectric layer 12A' is disposed at one end of the laser rod, and the partially-reflective dielectric layer 13A' is disposed at the other end of the laser rod to form a monolithic laser cavity in which laser light is emitted from the partially-reflective end of the laser rod. Preferably, the dielectric layer facing the pump light is also anti-reflective at the pump light wavelength. Figure 2A and Figure 2BThe cavity mirrors and dielectric layers can be mixed. For example, a high-reflection dielectric layer 12A' is set at one end of the laser rod, and a second cavity mirror 17' (laser output coupler) is set at the other end of the tapered laser gain module 20 / 20A / 20B / 20C / 20D / 20E / 20H / 20I / 20J to form a laser resonance cavity.

[0040] Figure 3 is a schematic diagram of a single-cone laser gain module according to a first embodiment of the present invention. Figure 3 Specifically, in this embodiment, the tapered laser gain module 20 includes a pump light source 100, a laser rod 300 whose end surface is coated with a first dielectric layer 30 and a second dielectric layer 40, and a tapered structure 400. The first dielectric layer 30 is disposed on a pump light incident side 400S1 of the tapered structure 400, and the second dielectric layer 40 is disposed on a pump light emitting side 400S2 of the tapered structure 400.

[0041] In this embodiment, the pump light source 100 is used to emit pump light SL and SL' along the laser emission axis LEA. For example, the pump light source 100 is a light emitting diode (LED) array, a laser diode (LD) array, or an array of a combination of a light emitting diode and a laser diode. The pump light SL and SL' are emitted around the cone axis.

[0042] In this embodiment, the laser rod 300 is arranged on the power flow path of the pump light SL and SL'. In addition, the laser rod 300 is arranged along the laser emission axis LEA and is used to absorb the pump light SL and SL' of the first wavelength to generate the amplified laser AL at the laser wavelength, wherein the long axis LA of the laser rod 300 is aligned parallel to the laser emission axis LEA. The laser rod (laser gain medium) 300 is made of one of Nd:YAG, Nd:Glass, Nd:YAP, Yb:YAG, Ho / Cr / Tm:YAG, Nd:YVO4, Er:YAG, Cr:LiSAF, Ti:Sapphire, Cr / Er:YSGG, Alexandrite and Er:Glass crystals. The amplified laser AL can be amplified from the fluorescence of the pump laser rod or the seed laser injected from the outside. Taking Nd:YAG laser as an example, the wavelength of the pump light SL and SL' is 808nm, and the wavelength of the amplified laser AL is 1064nm Nd 3+ Emission line.

[0043] In this embodiment, the tapered structure 400 having an internal reflection surface is used to accommodate the laser rod 300, receive the pump lights SL and SL', and reflect the off-axis pump light SL' to the laser rod 300. Specifically, the tapered structure 400 is used to reflect the divergent pump light SL' that initially misses the laser rod 300 back to the laser rod 300, wherein the cone axis CA of the tapered structure 400 is aligned parallel to the long axis LA of the laser rod 300. In one embodiment, the laser emission axis LEA is also aligned parallel to the long axis LA of the laser rod 300, but the present invention is not limited thereto.

[0044] In the present embodiment, the pump lights SL and SL′ emitted from the pump light source 100 enter the tapered structure 400 from the pump light incident side 400S1 of the tapered structure 400, and in this case, the output laser light L is emitted from the pump light emitting side 400S2 of the tapered structure 400. However, if a transmission hole ( Figure 8C 100-H in the conical structure 400), the laser light can also be emitted from the opposite side (not shown in the figure). The pump light incident side 400S1 and the pump light exit side 400S2 are opposite to each other. The off-axis pump light SL' that initially misses the laser rod 300 is reflected by the inner surface 400S4 of the conical structure 400 and is concentrated on the laser rod 300. In addition, the aperture of the pump light incident side 400S1 of the conical structure 400 is larger than the aperture of the pump light exit side 400S2 of the conical structure 400.

[0045] That is, the pump light SL and SL' emitted by the pump light source 100 enters the tapered structure 400 from the large aperture of the cone. The coaxial or proximal pump light SL is immediately intercepted and absorbed by the coaxial laser rod 300. The off-axis pump light SL' that initially misses the laser rod 300 is reflected by the inner surface 400S4 of the tapered structure 400 and concentrated on the laser rod 300. The laser rod 300 is used to absorb the pump light SL and SL' of the first wavelength to emit a laser signal of another wavelength along the rod axis. Preferably, the pump incident surface of the laser rod 300 is optically plated with an anti-reflection dielectric layer of the first wavelength or the pump light wavelength to maximize the transmission of the pump light.

[0046] In one embodiment, the inner surface 400S4 of the tapered structure 400 is made of a reflective metal, dielectric or ceramic. For example, when the tapered structure 400 is made of a transparent dielectric, the off-axis pump light SL′ that initially misses the laser rod 300 is reflected by the inner surface 400S4 and focused on the laser rod 300 by total internal reflection.

[0047] In one embodiment, the cross section (perpendicular to the cone axis CA) of the conical structure 400 is a full circle (eg Figure 5B As shown), partial circles (as Fig. 9B As shown), square (as Figure 7Bas shown), rectangular or polygonal (as Fig. 11B shown).

[0048] In this embodiment, the tapered laser gain module 20 further includes a heat sink / cooling plate 200. The heat sink / cooling plate 200 is attached to the pump light source 100 for heat dissipation.

[0049] In addition, in this embodiment, the first dielectric layer 30 is preferably anti-reflective at the pump light wavelength to maximize the transmission of the pump lights SL and SL'. Figure 1A When the laser amplifier has transmission holes in both the pump light source 100 and the heat sink / cooling plate 200 (refer to Figure 8C ), the first dielectric layer 30 and the second dielectric layer 40 are both anti-reflective at the laser wavelength to maximize the transmission rate of the seed laser and the amplified laser. For example, if the laser rod 300 is a Nd 3+ doped gain medium, the pump side / first dielectric layer 30 can be anti-reflective at both 808nm and 1064nm for the pump wavelength and the seed wavelength, and the second dielectric layer 40 can be anti-reflective at 808nm and 1064nm for the output laser. Figure 2B In order to establish laser oscillation, the dielectric layers 30, 40 may be highly reflective at the laser wavelength and partially reflective at the other. 3+ By doping the gain medium, the pump-side dielectric layer can be anti-reflective at 808 nm, and the two dielectric layers can be one highly reflective and the other partially reflective at 1064 nm for laser oscillation.

[0050] Based on the above, the tapered laser amplifier 10 or the laser gain module 20 in the embodiment of the present invention includes a tapered structure 400. The tapered structure 400 is used to reflect the divergent pump light SL' that initially misses the laser rod 300 back to the laser rod 300. Therefore, off-axis light, such as the pump light SL', can be reflected and concentrated on the laser rod 300 to improve the pumping efficiency, thereby increasing the gain of laser amplification or laser oscillation.

[0051] Figure 4 is a schematic diagram of a single-cone laser gain module with fluorescent material according to a second embodiment of the present invention. Figure 4 The tapered laser gain module 20A of this embodiment is Figure 3 The conical laser gain module 20A is similar to the conical laser gain module 20, but the difference is that the conical laser gain module 20A further includes a coating on the inner surface 400S4 (such as Figure 3The fluorescent material 500 is filled in the conical structure 400 or directly grown in the laser rod 300. The fluorescent material 500 is used to absorb the pump light SL and SL' of the first wavelength to generate the fluorescent light F of the second wavelength, and the laser rod 300 absorbs the fluorescent light F to generate the amplified laser light AL of the laser wavelength. For example, the fluorescent material 500 is doped with cerium (Ce) or chromium (Cr 3+ ) which can be excited by the visible light from the pump light source 100 to emit yellow / red light or near-infrared light to pump the laser rod 300 (e.g. Nd 3+ In this case, the active ions in the laser rod 300 may not be suitable for directly absorbing the light from the pump light source 100, but are suitable for receiving the fluorescence F as pump for the laser transition.

[0052] Figure 5A FIG. 4 is a schematic diagram of a single-taper laser gain module with a cooling water chamber according to a third embodiment of the present invention. Figure 5B yes Figure 5A Please refer to Figure 5A and Figure 5B The tapered laser gain module 20B of this embodiment is similar to the tapered laser gain modules 20 and 20A, except that the tapered laser gain module 20B further includes two hollow tubes 600 and a tapered water chamber. The two hollow tubes 600 are respectively disposed on the two openings O of the tapered structure 400 and are used to allow water W to flow in or out to cool the laser rod 300.

[0053] In this embodiment, the tapered laser gain module 20B further includes a rubber O-ring 700. The rubber O-ring 700 is used to seal the gap between the laser rod 300 and the tapered structure 400 to prevent water leakage.

[0054] Based on the above, since the tapered laser gain module 20B of this embodiment is provided with two hollow tubes 600 and a tapered water chamber, the tapered laser gain module 20B can remove waste heat generated by the laser rod 300 during the process of generating the amplified laser AL, so that the tapered laser gain module 20B can work continuously, stably and efficiently.

[0055] Fig. 6A FIG. 4 is a schematic diagram of a single-taper laser gain module with a cooling water pipe according to a fourth embodiment of the present invention. Figure 6B yes Fig. 6A Please refer to Fig. 6A and Figure 6B The tapered laser gain module 20C of this embodiment is similar to the tapered laser gain modules 20A and 20B, except that the tapered laser gain module 20C further includes a water pipe 800 surrounding the laser rod 300 and connecting the two hollow tubes 600.

[0056] Based on the above, since the tapered laser gain module 20C further includes the water pipe 800 for confining cooling water near the laser rod 300, the absorption of pump light in water can be reduced compared with the tapered laser gain module 20B.

[0057] Fig. 7A FIG. 4 is a schematic diagram of a single-taper laser gain module with end pumping and side pumping according to a fifth embodiment of the present invention. Figure 7B yes Fig. 7A Please refer to Fig. 7A and Figure 7B The conical laser gain module 20D of this embodiment is similar to the conical laser gain modules 20A, 20B, and 20C, except that the conical laser gain module 20D further includes a side pump light source 900. The side pump light source 900 is disposed around the reflective side 400S3 of the conical structure 400 to emit additional pump light to the laser rod 300, wherein the reflective side 400S3 is connected to the pump light exit side 400S2 and the pump light incident side 400S1. In addition, in this embodiment, the conical structure 400 is preferably made of a dielectric that is transparent to the pump light, and the surface 400S3 / 400S4 is a total internal reflection or grazing incidence surface of the light from the end pump light source 100. In fact, the side pump light source 900 may completely cover the sidewalls of the conical structure 400. For clarity, Fig. 7A Only partial coverage of the side pump light source 900 on the side wall is shown.

[0058] Based on the above, since the tapered laser gain module 20D of this embodiment is additionally provided with a side pump light source 900 , the gain of the laser module is further improved.

[0059] Fig. 8A is a schematic diagram of a double-tapered laser gain module according to a sixth embodiment of the present invention. Figure 8B yes Fig. 8A Left cross-sectional view of the pump light source 100-1 in FIG. Figure 8C yes Fig. 8A The right side cross-sectional view of the assembly of the pump light source 100-2 and the heat sink / cooling plate 200-2 in FIG. Fig. 8A , Figure 8B and Figure 8CThe double-side pumped tapered laser gain module 20E of this embodiment has two cascaded tapered laser gain modules, similar to 20, 20A, 20B, 20C and 20D. Specifically, the double-side pumped tapered laser gain module 20E includes two pump light sources 100-1, 100-2 and two tapered structures 400E-1 and 400E-2 aligned in a collinear manner and facing each other. The two pump light sources 100-1, 100-2, such as LEDs or LDs, are used to emit pump lights SL-1, SL-2 around the cone axis CA from opposite sides of two large cone holes.

[0060] Specifically, in this embodiment, two pump light sources 100-1 and 100-2 are used to emit pump light SL-1 and SL-2 along the laser emission axis LEA. Two tapered structures 400E-1 and 400E-2 with internal reflection surfaces are used to accommodate the laser rod 300, receive the pump light SL-1 and SL-2, and reflect the off-axis pump light to the laser rod 300, wherein the connected tapered axis CA is aligned parallel to the long axis LA of the laser rod 300. The on-axis or near-axis pump light is immediately intercepted and absorbed by the coaxial laser rod 300. Some off-axis pump light that initially misses the laser rod 300 is reflected by the inner surfaces of the two tapered structures 400 and concentrated on the laser rod 300. The laser rod 300 is used to absorb the pump light of the first wavelength to emit a laser signal of another wavelength along the rod axis. Preferably, the pump incident surface of the laser rod is optically coated with an anti-reflection medium layer of the first wavelength or pump wavelength to maximize the transmission of the pump light.

[0061] In detail, the two tapered structures 400E-1 and 400E-2 are used to reflect the divergent light of the pump lights SL-1 and SL-2 that initially misses the laser bar 300 back to the laser bar 300, wherein the collinear tapered axes CA of the two tapered structures 400E-1 and 400E-2 are aligned parallel to the long axis LA of the laser bar 300. The pump lights SL-1 and SL-2 emitted from the two pump light sources 100-1 and 100-2 enter the two tapered structures 400E-1 and 400E-2 from the pump light incident sides 400-1S1 and 400-2S1, respectively, and the output laser light L is emitted from the laser bar 300. The two pump light incident sides 400-1S1 and 400-2S1 are opposite to each other. The pump light incident side 400-1S1 and 400-2S1 of each tapered structure 400E-1 and 400E-2 and the pump light emitting side 400-1S2 and 400-2S2 are opposite to each other, and the pump light emitting sides 400-1S2 and 400-2S2 of the two tapered structures 400E-1 and 400E-2 are connected. The divergent pump light that initially misses the laser rod 300 is reflected by the inner surfaces 400-1S4 and 400-2S4 of the two tapered structures 400E-1 and 400E-2 and is concentrated on the laser rod 300. The apertures of the pump light incident sides 400-1S1 and 400-2S1 of the two tapered structures 400E-1 and 400E-2 are respectively larger than the apertures of the pump light exiting sides 400-1S2 and 400-2S2 of the two tapered structures 400E-1 and 400E-2.

[0062] In addition, one or both of the pump light sources 100-1 and 100-2 have a transmission hole along the cone axis CA, so that the amplified laser light AL can pass through one or both of the pump light sources 100-1 and 100-2 to generate the output laser light L (refer to Figure 1A , 1B , 2A, 2B). In this example, Figure 8C The pump light source 100 - 2 is shown to have a transmission hole 100 -H for transmitting the output laser light L.

[0063] In this embodiment, the double-side pumped tapered laser gain module 20E further includes heat sinks / cooling plates 200-1 and 200-2. The heat sinks / cooling plates 200-1 and 200-2 are attached to the pump light sources 100-1 and 100-2, respectively, to dissipate heat.

[0064] In addition, in this embodiment, the double-side pumped tapered laser gain module 20E further includes a first dielectric layer 30 and a second dielectric layer 30, 40 located on both end surfaces of the laser rod 300, and the specifications of the tapered laser gain modules 20, 20A, 20B, 20C, 20D are the same, except that the double-side pumped tapered laser gain module 20E is used as Figure 2A or Figure 2BWhen using a laser oscillator in a cavity, an external cavity mirror or an output coupler close to the pump source and the transmission hole on the heat sink / cold plate assembly can be used.

[0065] Based on the above, since the double-side pumped tapered laser gain module 20E of this embodiment includes two pumping light sources 100 - 1 and 100 - 2 , the gain of the laser module is further increased.

[0066] Fig.9A FIG. 4 is a schematic diagram of a single-part tapered laser gain module according to a seventh embodiment of the present invention. Fig. 9B yes Fig.9A Please refer to the right section of Fig.9A and Fig. 9B The tapered laser gain module 20H of this embodiment is Figure 3 The tapered laser gain module 20H is similar to the tapered laser gain module 20, except that the tapered laser gain module 20H further includes a cooling element 1000 located below, and the cooling element 1000 is used to remove waste heat from the laser rod 300. The cooling element 1000 is directly attached to the laser rod 300. The cooling element 1000 is, for example, a heat sink or a cooling plate. Compared with the water cooling scheme in the previous embodiment, this embodiment has the advantage of direct solid-state cooling of the laser rod.

[0067] In addition, in this embodiment, the cross section of the circular structure 400H is a partial circle. The laser emission axis LEA is parallel to the cone axis CA, but the laser emission axis LEA is not necessarily aligned with the cone axis CA.

[0068] Fig.10 is a schematic diagram of a double-part tapered laser gain module according to an eighth embodiment of the present invention. Fig.10 The double-side pumped tapered laser gain module 20I of this embodiment is Fig. 8A The double-side pumped tapered laser gain module 20E is similar to the double-side pumped tapered laser gain module 20I, but the difference is that the double-side pumped tapered laser gain module 20I further includes a cooling element 1000 located below, and the cooling element 1000 is used to remove waste heat from the laser rod 300. The cooling element 1000 is connected to the laser rod 300. The cooling element 1000 is, for example, a heat sink or a cooling plate.

[0069] In addition, in this embodiment, the cross-section of the conical structures 400I-1 and 400I-2 is a partial circle. The laser emission axis LEA is parallel to the cone axis CA, but the laser emission axis LEA is not necessarily aligned with the cone axis CA.

[0070] Fig.11A FIG. 4 is a schematic diagram of a partially tapered laser gain module with end pumping and side pumping according to a ninth embodiment of the present invention. Fig. 11B yes Fig.11A Please refer to the right section of Fig.11A and Fig. 11B The tapered laser gain module 20J of this embodiment is Fig. 7A The tapered laser gain module 20I is similar to the tapered laser gain module 20D, but differs in that the tapered laser gain module 20I further includes a cooling element 1000 located below, and the cooling element 1000 is used to remove waste heat from the laser rod 300. The cooling element 1000 is connected to the laser rod 300. The cooling element 1000 is, for example, a heat sink or a cooling plate.

[0071] In addition, in this embodiment, the cross section of the conical structure 400J is a polygon. The laser emission axis LEA is parallel to the cone axis CA, but the laser emission axis LEA is not necessarily aligned with the cone axis CA.

[0072] When the laser module in the above embodiment is used as Figure 1A In the case of laser amplifiers, the dielectric layers 30, 40 are anti-reflective at the laser wavelength, and Figure 8C The transmission hole 100-H in the pump light source and the heat sink / cooling plate assembly is opened for laser injection or laser output. As mentioned above, by using an external cavity with two cavity mirrors, Figure 1A The laser amplifier module converts Figure 2A This conversion is advantageous and flexible in optimizing laser performance by replacing mirrors of different designs.

[0073] Based on the above embodiments of the present invention, the single-taper laser gain module, double-taper laser gain module, partial-taper laser gain module, tapered laser amplifier or tapered laser oscillator of the present invention all include a tapered structure with an inner reflection surface of a closed tapered axis, which can reflect, collect, concentrate and recycle side pump light to the laser rod to achieve efficient laser pumping. The present invention is particularly suitable for artificial divergent light sources, such as LEDs and LDs, to pump laser gain media and generate laser light.

[0074] It will be apparent to those skilled in the art that various modifications and variations may be made to the disclosed embodiments without departing from the scope or spirit of the present disclosure. For example, cascading the laser gain modules of the present invention along the cone axis may further increase the gain of laser amplification or laser oscillation. In view of the foregoing, the present disclosure is intended to cover modifications and variations that fall within the scope of the appended claims and their equivalents.

Claims

1. A tapered laser gain module, characterized in that: include: A pump light source, used to emit a plurality of pump lights around the laser emission axis; a laser rod, whose long axis is parallel to the laser emission axis, disposed in a power flow path of the plurality of pump lights and used for absorbing the plurality of pump lights to generate a plurality of amplified laser lights of another wavelength along the laser emission axis; and a tapered structure for accommodating the laser rod and for limiting the plurality of pump lights toward the laser rod, wherein the cone axis of the conical structure is aligned parallel to the laser emission axis, wherein the plurality of pump lights emitted from the pump light source enter the tapered structure from a larger tapered hole to a smaller tapered hole, Among the plurality of pump lights, some pump lights that diverge and initially miss the laser rod are reflected by the inner surface of the tapered structure and concentrated on the laser rod.

2. The laser gain module according to claim 1, characterized in that: The pump light source is a light emitting diode array, a laser diode array or an array of a combination of light emitting diodes and laser diodes.

3. The laser gain module according to claim 1, characterized in that: A heat sink or cooling plate is also included, which is attached to the pump light source to dissipate heat.

4. The laser gain module according to claim 1, characterized in that: The cross section of the conical structure is fully circular, partially circular, square, rectangular or polygonal.

5. The laser gain module according to claim 1, characterized in that: The inner surface of the conical structure is made of reflective metal, dielectric or ceramic.

6. The laser gain module according to claim 1, characterized in that: The laser rod is made of one of Nd:YAG, Nd:Glass, Nd:YAP, Yb:YAG, Ho / Cr / Tm:YAG, Nd:YVO4, Er:YAG, Cr:LiSAF, Ti:Sapphire, Cr / Er:YSGG, alexandrite and Er:Glass crystals.

7. The laser gain module according to claim 1, characterized in that: It also includes a plurality of fluorescent materials coated on the inner surface of the conical structure or filled in the conical structure, wherein the plurality of luminescent materials are used to absorb the plurality of pump lights of the first wavelength to generate a plurality of fluorescent lights of the second wavelength. The laser rod absorbs the plurality of fluorescent lights to generate the plurality of amplified lasers.

8. The laser gain module according to claim 1, characterized in that: Two hollow tubes are also included to allow water to flow into or out of the conical structure to cool the laser rod.

9. The laser gain module according to claim 8, characterized in that: The invention also comprises a water pipe which is contained in the conical structure, surrounds the laser rod and connects the two hollow tubes to cool the laser rod.

10. The laser gain module according to claim 1, characterized in that: Also included are a plurality of side pump light sources disposed around a plurality of lateral sides of the tapered structure and configured to emit a plurality of additional pump lights of the first wavelength toward the laser rod.

11. The laser gain module according to claim 1, characterized in that: Also includes a cooling element connected below the laser rod, The cooling element is a heat sink or a cooling plate.

12. A tapered laser amplifier, characterized in that: include: The laser gain module according to claim 1; as well as A seed laser is used to inject seed light into the tapered laser gain module for amplification.

13. A tapered laser oscillator, characterized in that: include: The laser gain module according to claim 1; Laparoscope; as well as An output coupling mirror, wherein the tapered laser gain module is mounted between the cavity mirror and the output coupling mirror.

14. A tapered laser gain module, characterized in that: include: Two pump light sources, used to emit a plurality of pump lights of a first wavelength along a laser emission axis; a laser rod, whose long axis is parallel to the laser emission axis, disposed in a power flow path of the plurality of pump lights and used for absorbing the plurality of pump lights to generate a plurality of amplified laser lights of another wavelength along the laser emission axis; and Two conical structures, having a colinear conical axis connecting two smaller conical holes, for accommodating the laser rod and for confining the plurality of pump lights toward the laser rod, wherein the collinear cone axes of the two cone structures are aligned parallel to the laser emission axis, wherein the plurality of pump lights emitted from the two pump light sources enter the two tapered structures from the two larger tapered holes toward the two connected smaller tapered holes, Among the plurality of pump lights, some of the pump lights that diverge and initially miss the laser rod are reflected by the plurality of inner surfaces of the two tapered structures and concentrated on the laser rod.

15. A tapered laser amplifier, characterized in that: include: The tapered laser gain module according to claim 14; as well as A seed laser is used to inject seed light into the tapered laser gain module for amplification.

16. A tapered laser oscillator, characterized in that: include: The tapered laser gain module according to claim 14; Laparoscope; as well as An output coupling mirror, wherein the tapered laser gain module is mounted between the cavity mirror and the output coupling mirror.

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