Tunable terahertz burst mode for pulsed lasers

Abstract

A tunable pulse burst mode laser includes a beam splitting optical element; a plurality of optical path difference (OPD) tuning elements; a plurality of optical amplifiers; and a beam combining optical element. The beam splitting optical element is configured to split an input beam into a plurality of beams to propagate via a plurality of optical paths. The plurality of OPD tuning elements are configured to modify respective lengths of the plurality of optical paths. The plurality of optical amplifiers are configured to amplify respective optical powers of the plurality of light beams. The beam combining optical element is configured to combine the plurality of light beams into an output beam comprising a plurality of pulsed light beams, where a particular pulsed light beam comprises a plurality of beamlets from the plurality of light beams, respectively, and where the plurality of beamlets are provided in the form of terahertz (THz) bursts.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 510,845, entitled “Terahertz (THz) Adjustable Burst for Pulsed Lasers,” filed on June 28, 2023. The disclosure of that prior application is considered part of and incorporated by reference into this patent application. Technical Field

[0003] The present disclosure relates generally to pulsed lasers and tunable terahertz (THz) burst modes for pulsed lasers. Background Art

[0004] For ultrashort pulse (USP) lasers, such as those used for material processing, a common mode of operation is the so-called "burst mode." In burst mode, a group of closely spaced pulses is emitted (usually at a regular frequency / scheduling). The time interval between each pulse of a group of pulses within a burst can be smaller than the time interval between groups of pulses. Summary of the invention

[0005] In some embodiments, a tunable pulse burst mode laser includes a beam splitting optical element; a plurality of optical path difference (OPD) tuning elements; a plurality of optical amplifiers; and a beam combining optical element, wherein: the beam splitting optical element is configured to split an input beam into a plurality of beams, the plurality of beams being transmitted from the beam splitting optical element to the beam combining optical element via a plurality of optical paths, the plurality of OPD tuning elements being respectively disposed on the plurality of optical paths and configured to modify the respective lengths of the plurality of optical paths, the plurality of optical amplifiers being respectively disposed on the plurality of optical paths and configured to amplify the respective optical powers of the plurality of beams, and the beam combining optical element being configured to combine the plurality of beams into an output beam including a plurality of pulse beams, wherein a specific pulse beam of the plurality of pulse beams includes a plurality of beamlets respectively from the plurality of beams, and wherein the plurality of beamlets are provided in the form of terahertz (THz) bursts.

[0006] In some embodiments, a tunable pulse burst mode laser includes a beam splitting optical element; a plurality of OPD tuning elements; and a beam combining optical element, wherein: the beam splitting optical element is configured to split an input beam into a plurality of beams, the plurality of beams will propagate from the beam splitting optical element to the beam combining optical element via a plurality of optical paths, the plurality of OPD tuning elements are respectively arranged in the plurality of optical paths, and the beam combining optical element is configured to combine the plurality of beams into an output beam including a pulsed beam, the pulsed beam including a plurality of beamlets respectively from the plurality of beams, wherein the plurality of beamlets are provided in a burst form, and wherein the amount of time between consecutive beamlets within the burst is less than or equal to 1 picosecond (ps).

[0007] In some embodiments, a tunable pulse burst mode laser includes a beam splitting optical element; a plurality of OPD tuning elements; and a beam combining optical element, wherein: the beam splitting optical element is configured to split an input beam into a plurality of beams, the plurality of OPD tuning elements are respectively arranged on a plurality of optical paths of the plurality of beams, and the beam combining optical element is configured to combine the plurality of beams into an output beam, the output beam including a pulse beam comprising a plurality of beamlets, and wherein the plurality of beamlets are provided in the form of a tunable THz burst. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1A-1F is a schematic diagram of an example associated with a tunable THz burst mode of a pulsed laser.

[0009] Figure 2A-2D is a schematic diagram of an example associated with a tunable burst mode of a pulsed laser.

[0010] Figure 3A-3B is a schematic diagram of an example associated with a tunable burst mode of a pulsed laser.

[0011] Figure 4A-4B is a schematic diagram of an example associated with a tunable burst mode of a pulsed laser. DETAILED DESCRIPTION

[0012] The following detailed description of example implementations refers to the accompanying drawings.The same reference numbers in different drawings may identify the same or similar elements.

[0013] Pulsed lasers can use bursts, such as megahertz (MHz) bursts (e.g., the minimum time interval between two consecutive pulses within a burst is about (a few) 10 nanoseconds (ns)), to keep the pulse energy / flux low / moderate while increasing the average power of the output beam. This can be useful in material processing, where increased average power can increase material removal rates, while moderate pulse energy / flux can maintain high processing / ablation quality. However, the use of bursts can cause heat accumulation problems in some processes, which affects the performance of pulsed lasers in these processes. It is worth noting that in many cases, heat deposition can be more accurately controlled by reducing the time interval between individual pulses within a burst, adjusting the total number of pulses within a burst, and tuning the energy of individual pulses within a burst, such as reducing the pulse energy, increasing the number of pulses within a burst, and reducing the time interval between pulses within a burst. Accordingly, there is a need for pulsed lasers to provide pulses with frequencies greater than MHz to allow increased power processing with improved heat accumulation control.

[0014] Pulsed lasers can be configured to provide gigahertz (GHz) bursts, where the minimum time interval between two consecutive pulses in a burst is approximately 1 nanosecond (ns). For example, a pulsed laser can include a laser oscillator with a GHz fundamental frequency, which allows the direct generation of GHz bursts. However, due to the limitation of the fundamental frequency of the laser oscillator, this technical method cannot be used to directly generate THz pulses. In some cases, a pulsed laser can include a birefringent crystal that can be stacked to produce multiple pulses with a small time interval in a burst. This can enable the generation of THz pulses, but the time interval is fixed (because the time interval is determined by the thickness of the birefringent crystal). In other words, a pulsed laser is non-tunable.

[0015] Some embodiments described herein include a pulsed laser that supports a tunable THz burst mode (e.g., a minimum time interval between two consecutive pulses within a burst is approximately 1 picosecond (ps)). The pulsed laser includes a beam splitting optical element, a beam combining optical element, a plurality of (e.g., two or more) optical amplifiers, and a plurality of OPD elements.

[0016] The beam splitting optical element is configured to split the input light beam into a plurality of light beams, which will propagate from the beam splitting optical element to the beam combining optical element via a plurality of light paths. Each optical amplifier can be disposed on the light path of the light beam and can be configured to amplify the optical power of the light beam (e.g., the light beam propagated through the optical amplifier). Each OPD tuning element can be disposed on the light path of the light beam and can be configured to modify the length of the light path. For example, the OPD tuning element can be a fine OPD tuning element and can be configured to modify the length of the light path within a fine tuning range (e.g., from 0 micrometers (μm) to 5 μm). As another example, the OPD tuning element can be a coarse OPD tuning element and can be configured to modify the length of the light path within a coarse tuning range (e.g., from 5 μm to 299 μm). In this way, a plurality of OPD tuning elements can cause a plurality of light beams to propagate to the beam combining optical element at different times, wherein the time interval between two consecutive times is less than or equal to 1 ps.

[0017] The beam combining optical element is configured to combine the multiple light beams into an output light beam. For example, the beam splitting optical element can be configured to spatially overlap beamlets of the multiple light beams to produce an output light beam.

[0018] In some embodiments, the pulsed laser is configured to promote a constructive interference condition of the multiple beams (e.g., by controlling the lengths of the respective optical paths of the multiple beams using multiple OPD tuning elements), which enables the output beam to be a single pulsed output beam. For example, the beam combining optical element can separate each beam into multiple beamlets, and the pulsed laser can be configured to cause the beamlets of each beam to constructively interfere to form the output beam into a single pulsed output beam. In this way, the pulsed laser can be configured to provide a non-burst mode.

[0019] Alternatively, in some embodiments, the pulsed laser is configured to facilitate incoherent beam combining conditions of multiple beams, such as by controlling the lengths of the respective optical paths of the multiple beams using multiple OPD tuning elements. This enables the output beam to include multiple pulsed beams. For example, the beam combining optical element can separate each beam into multiple beamlets to form multiple pulsed beams, wherein each pulsed beam includes a beamlet of at least one beam. Notably, a specific pulsed beam in the multiple pulsed beams includes a beamlet of each beam in the multiple beams. This allows the pulsed laser to operate in a burst mode, wherein the beamlets of a specific pulsed beam are provided in a burst form (e.g., continuously) (e.g., wherein each beamlet is temporally spaced a specific amount of time from the previous beamlet or the next beamlet). For example, the pulsed laser can provide beamlets in the form of THz bursts (e.g., the amount of time between consecutive beamlets can be less than or equal to 1 picosecond (ps)). In addition, because multiple OPD tuning elements can be configured to finely and / or roughly modify the optical path lengths of multiple beams, the burst is tunable. For example, the burst may be a tunable THz burst (eg, when the fine tuning range and the coarse tuning range are from 0 to 299 μm), or may be a tunable GHz to THz burst (eg, when the fine tuning range and the coarse tuning range are from 0 to 300 mm), etc.

[0020] In this manner, some embodiments described herein include a pulsed laser capable of providing (e.g., in non-burst mode) a single pulsed output beam. In addition, the pulsed laser is capable of providing (e.g., in burst mode) an output beam comprising a plurality of pulsed beams, wherein a particular pulsed beam comprises a beamlet provided in a burst form (e.g., continuously). For example, the pulsed laser can provide a beamlet in a THz burst form (e.g., the amount of time between consecutive beamlets is less than or equal to 1 ps). In addition, because the optical path lengths of the plurality of beams propagating through the pulsed laser can be finely and / or roughly modified, the burst is a tunable burst, such as a tunable THz burst or a GHz to THz burst.

[0021] Accordingly, pulsed lasers can be used for practical purposes, such as material processing (e.g., requiring pulsed lasers capable of providing pulses with frequencies greater than MHz). For example, pulsed lasers can provide bursts with increased average power and improved heat load control (e.g., due to smaller or lower time intervals between pulses in a burst and tunable individual pulse energies). This, therefore, improves the efficiency of material processing processes (such as laser ablation processes).

[0022] Figure 1A-1F is a schematic diagram of example 100 associated with a tunable THz burst mode of a pulsed laser. Figure 1A-1FAs shown, example 100 includes a pulsed laser 102 (eg, a tunable pulsed burst mode laser).

[0023] like Figure 1A-Figure 1D As shown, the pulsed laser 102 may include a beam splitting optical element 104, a plurality of fine optical path difference (OPD) tuning elements 106 (shown as fine OPD tuning elements 106-1 to 106-N), a plurality of coarse OPD tuning elements 108 (shown as coarse OPD tuning elements 108-1 to 108-N), a plurality of optical amplifiers 110 (shown as optical amplifiers 110-1 to 110-N) and / or a beam combining optical element 112.

[0024] The beam splitting optical element 104 can be configured to split the input light beam 114 into a plurality of light beams 116 (e.g., a plurality of sub-beams of the input light beam 114), such as N light beams 116 (shown as light beams 116-1 through 116-N). For example, the beam splitting optical element 104 can be configured to split the input light beam 114 into a plurality of light beams 116, which will propagate from the beam splitting optical element 104 via a plurality of optical paths 118 (e.g., respective optical paths of the plurality of light beams 116, shown as optical paths 118-1 through 118-N), as further described herein. The beam splitting optical element 104 can include, for example, a diffractive optical element (DOE), a segmented mirror, a conventional beam splitter (e.g., including one or more beam splitters and / or combiners, such as partial reflectors and / or polarizing beam splitters), and / or similar types of optical elements.

[0025] Each fine OPD tuning element 106 of the plurality of fine OPD tuning elements 106 may correspond to a light beam 116 of the plurality of light beams 116. Accordingly, each fine OPD tuning element 106 may be disposed on an optical path 118 of the light beam 116. For example, the fine OPD tuning element 106-1 may be disposed on an optical path 118-1 of the light beam 116-1, the fine OPD tuning element 106-2 may be disposed on an optical path 118-2 of the light beam 116-2, and so on. Each fine OPD tuning element 106 may be configured to modify the length of the optical path 118 (e.g., on which the fine OPD tuning element 106 is disposed) within a fine tuning range (this is sometimes referred to as phase delay control). The fine tuning range may be, for example, from 0 μm to 5 μm (e.g., greater than 0 μm and less than or equal to 5 μm), or another range associated with fine OPD tuning. The fine OPD tuning element 106 can be configured to modify the length of the optical path 118 (e.g., within a fine tuning range) with a resolution less than or equal to one-tenth of the wavelength (e.g., center wavelength) of the light beam 116, one-fiftieth of the wavelength of the light beam 116, or one-hundredth of the wavelength of the light beam 116, etc. Accordingly, the fine OPD tuning element 106 can include, for example, a micro-electromechanical system (MEMS) mirror, a liquid crystal on silicon (LCOS) optical element (also known as a spatial light modulator (SLM) or a liquid crystal modulator), a piezoelectrically actuated optical element (e.g., a piezoelectrically actuated mirror), an optical element with adjustable thickness (e.g., an optical element with adjustable thickness that is transparent to the signal wavelength, such as one or more glass wedges), an optical element with a tunable refractive index (e.g., an optical element with a tunable refractive index that is transparent to the signal wavelength, such as an electro-optic modulator optical element with a temperature-dependent refractive index that can be temperature controlled using a heater or a thermoelectric cooler (TEC)), and / or similar types of optical elements.

[0026] Each coarse OPD tuning element 108 of the plurality of coarse OPD tuning elements 108 may correspond to a beam 116 of the plurality of beams 116. Accordingly, each coarse OPD tuning element 108 may be disposed on an optical path 118 of the beam 116. For example, the coarse OPD tuning element 108-1 may be disposed on an optical path 118-1 of the beam 116-1, the coarse OPD tuning element 108-2 may be disposed on an optical path 118-2 of the beam 116-2, and so on. Each coarse OPD tuning element 108 may be configured to modify the length of the optical path 118 within a coarse tuning range (this is sometimes referred to as group delay control). The coarse tuning range can be, for example, from 5 μm to 299 μm (e.g., greater than 5 μm and less than or equal to 299 μm), or another range associated with coarse OPD tuning (e.g., from 5 μm to 500 μm, from 5 μm to 1 millimeter (mm), from 5 μm to 10 mm, from 5 μm to 100 mm, or from 5 μm to 300 mm, etc.). The coarse OPD tuning element 108 can be configured to modify the length of the optical path 118 (e.g., within the coarse tuning range) with a resolution less than or equal to one-tenth of the wavelength (e.g., center wavelength) of the light beam 116, one-fiftieth of the wavelength of the light beam 116, or one-hundredth of the wavelength of the light beam 116, etc. Accordingly, the coarse OPD tuning element 108 can include, for example, a translation stage (e.g., an electric translation stage or a piezoelectric translation stage, etc.), a piezoelectrically actuated optical element (e.g., a piezoelectrically actuated mirror), and / or similar types of optical elements.

[0027] Each optical amplifier 110 of the plurality of optical amplifiers 110 may correspond to a light beam 116 of the plurality of light beams 116. Accordingly, each optical amplifier 110 may be disposed on an optical path 118 of the light beam 116. For example, the optical amplifier 110-1 may be disposed on an optical path 118-1 of the light beam 116-1, the optical amplifier 110-2 may be disposed on an optical path 118-2 of the light beam 116-2, and so on. Each optical amplifier 110 may be configured to amplify the optical power of the light beam 116 (e.g., a light beam propagating through the optical amplifier 110). For example, the optical amplifier 110 may include a gain medium energized by a source such as a pump laser. The gain medium may include, for example, a glass fiber doped with rare earth ions (e.g., erbium, neodymium, ytterbium, praseodymium, or thulium), a crystal doped with rare earth ions, or a waveguide doped with a material, and the like.

[0028] The beam combining optical element 112 can be configured to combine the plurality of light beams 116 into an output light beam 120. For example, the beam splitting optical element 104 can be configured to spatially overlap portions (e.g., beamlets) of the plurality of light beams 116 (e.g., portions that propagate to the beam combining optical element 112 via corresponding optical paths 118, as further described herein) to produce the output light beam 120. Accordingly, the beam combining optical element 112 can include, for example, a DOE, a segmented mirror, a conventional beam splitter, and / or similar types of optical elements.

[0029] like Figure 1E-1F As shown, the pulsed laser 102 may include a beam splitting optical element 104, a plurality of optical amplifiers 110, a beam combining optical element 112 and / or a plurality of fine and coarse OPD tuning elements 122 (shown as fine and coarse OPD tuning elements 122-1 to 122-N) (e.g., in place of separate fine OPD tuning elements 106 and coarse OPD tuning elements 108).

[0030] Each of the plurality of fine and coarse OPD tuning elements 122 may correspond to a beam 116 of the plurality of beams 116. Accordingly, each of the fine and coarse OPD tuning elements 122 may be disposed on an optical path 118 of the beam 116. For example, the fine and coarse OPD tuning element 122-1 may be disposed on an optical path 118-1 of the beam 116-1, the fine and coarse OPD tuning element 122-2 may be disposed on an optical path 118-2 of the beam 116-2, and so on. Each of the fine and coarse OPD tuning elements 122 may be configured in the same or similar manner as the fine OPD tuning element 106 and the coarse OPD tuning element 108. Each of the fine and coarse OPD tuning elements 122 may be configured to modify the length of the optical path 118 within a fine and coarse tuning range (this is sometimes referred to as phase delay and group delay control). The fine and coarse tuning ranges may be, for example, from 0 μm to 299 μm (e.g., greater than 0 μm and less than or equal to 299 μm), or another range associated with fine and coarse OPD tuning (e.g., from 0 μm to 500 μm, from 0 μm to 1 millimeter (mm), from 0 μm to 10 mm, from 0 μm to 100 mm, or from 0 μm to 300 mm, etc.). The fine and coarse OPD tuning elements 122 may be configured to modify the length of the optical path 118 (e.g., within the fine tuning range) with a resolution less than or equal to one-tenth of the wavelength (e.g., center wavelength) of the light beam 116, one-fiftieth of the wavelength of the light beam 116, or one-hundredth of the wavelength of the light beam 116, etc. Accordingly, the fine and coarse OPD tuning elements 122 may include, for example, MEMS mirrors, LCOS optical elements, piezoelectrically actuated optical elements, tunable optical elements, refractive index tunable optical elements, translation stages, and / or similar types of optical elements.

[0031] like Figure 1A-1F As shown, the fine OPD tuning element 106, the coarse OPD tuning element 108, the optical amplifier 110, and / or the fine and coarse OPD tuning element 122 may be disposed on each optical path 118 of the plurality of light beams 116. Accordingly, when the light beam 116 propagates on the optical path 118 from the beam splitting optical element 104 to the beam combining optical element 112, the light beam 116 may propagate to or from at least one of the fine OPD tuning element 106, the coarse OPD tuning element 108, the optical amplifier 110, or the fine and coarse OPD tuning element 122.

[0032] For example, Figure 1A As shown, for optical path 118, light beam 116 may propagate to fine OPD tuning element 106, then to coarse OPD tuning element 108, and then to optical amplifier 110 before propagating to beam combining optical element 112. As another example, Figure 1B As shown, for optical path 118, light beam 116 may propagate to fine OPD tuning element 106, then to optical amplifier 110, and then to coarse OPD tuning element 108 before propagating to beam combining optical element 112. In another example, as shown in FIG. Figure 1C As shown, for optical path 118, light beam 116 may propagate to coarse OPD tuning element 108, then to optical amplifier 110, and then to fine OPD tuning element 106 before propagating to beam combining optical element 112. In additional examples, as shown in FIG. Figure 1D As shown, for optical path 118, light beam 116 may propagate to optical amplifier 110, then to fine OPD tuning element 106, and then to coarse OPD tuning element 108 before propagating to beam combining optical element 112. As another example, Figure 1E As shown, for optical path 118, light beam 116 may propagate to fine and coarse OPD tuning elements 122 and then to optical amplifier 110 before propagating to beam combining optical element 112. In another example, as shown in FIG. Figure 1F As shown, for optical path 118 , light beam 116 may propagate to optical amplifier 110 and then to fine and coarse OPD tuning elements 122 before propagating to beam combining optical element 112 .

[0033] Accordingly, for the light beam 116 propagating from the beam separating optical element 104 to the beam combining optical element 112 via the optical path 118, the fine OPD tuning element 106 disposed on the optical path 118 can finely modify the length of the optical path 118 (e.g., modify the length by an amount within a fine tuning range); the coarse OPD tuning element 108 disposed on the optical path 118 can coarsely modify the length of the optical path 118 (e.g., modify the length by an amount within a coarse tuning range); the fine and coarse OPD tuning elements 122 disposed on the optical path 118 can finely and / or coarsely modify the length of the optical path 118 (e.g., modify the length by an amount within a fine and coarse tuning range); and / or the optical amplifier 110 disposed on the optical path 118 can amplify the optical power of the light beam 116. In this way, multiple light beams 116 can propagate via corresponding optical paths 118 to the beam combining optical element 112 (e.g., after each light beam 116 is modified by the fine OPD tuning element 106, the coarse OPD tuning element 108, the optical amplifier 110 and / or the fine and coarse OPD tuning elements 122).

[0034] The beam combining optical element 112 can combine the plurality of light beams 116 into an output light beam 120. In some embodiments, the pulsed laser 102 can be configured to promote a constructive interference condition of the plurality of light beams 116 (e.g., by controlling the lengths of the respective optical paths 118 of the plurality of light beams 116), which can cause the output light beam 120 to be a single pulsed output light beam. For example, the beam combining optical element 112 can combine each light beam 116 (e.g., a first number of light beams 116, such as Figure 1A-1F The N light beams 116 shown in FIG. 1 are separated into a plurality of light beams (eg, a second number of light beams, such as Figure 1A-1F The pulsed laser 102 may be configured to constructively interfere the second number of beamlets of each beam 116 in the first number of beams 116 to form the output beam 120 as a single pulsed output beam. Accordingly, the optical power of the output beam 120 may be the same as the total number of beamlets (e.g., N beams 116) of the first number of beams 116. 2 The sum of the optical powers of the first number of light beams 116 may be calculated by multiplying the optical powers of the first number of light beams 116 by the plurality of optical amplifiers 110, such as after the first number of light beams 116 have been amplified by the plurality of optical amplifiers 110.

[0035] Alternatively, in some embodiments, the pulsed laser 102 can be configured to promote an incoherent beam combining condition of the plurality of light beams 116 (e.g., an incoherent summation of the electric fields of the plurality of light beams 116), such as by controlling the lengths of the respective optical paths 118 of the plurality of light beams 116. This can result in the output light beam 120 comprising a plurality of pulsed light beams (in Figure 1A-1FFor example, the beam combining optical element 112 may combine each of the beams 116 (eg, each of the beams 116 of the first number of beams 116, such as Figure 1A-1F The N light beams 116 shown in FIG. 1 are separated into a plurality of light beams (a second number of light beams, such as N light beams, not shown in FIG. 1 ). Figure 1A-1F 116) to form a plurality of pulsed beams (e.g., M pulsed beams, where M>N), wherein each pulsed beam includes a beamlet of at least one beam 116. It is noteworthy that a specific pulsed beam among the plurality of pulsed beams, such as a central pulsed beam, may include a beamlet of each beam 116 among the plurality of beams 116. For example, the specific pulsed beam may include a third number of beamlets (e.g., N beamlets) respectively from the first number of beams 116 (e.g., N beams 116). Accordingly, the optical power of the specific pulsed beam may be the sum of the optical powers of the third number of beamlets (e.g., after the first number of beams 116 are amplified by the plurality of optical amplifiers 110). In other words, the optical power of the specific pulsed beam may be less than or equal to the optical power of the output beam 120 (e.g., the total optical power of the output beam 120) divided by a third quantity (e.g., divided by N).

[0036] Additionally, in some embodiments, the plurality of light beams 116 may each have a tunable amount of energy (e.g., based on the configuration of the respective optical amplifiers 110 through which the plurality of light beams 116 propagate). For example, each optical amplifier 110 may be configured to tune the amplitude of the light beam 116 to a particular amplitude level (e.g., by adjusting the optical amplifier coupling efficiency; adjusting the optical amplifier coupling alignment; and / or introducing adjustable amplifier losses, such as by including a variable attenuator and / or a variable amplifier; etc.). Accordingly, the beam combining optical element 112 may separate each light beam 116 into a plurality of beamlets, each beamlet having a particular amount of energy, to form a plurality of pulsed light beams (e.g., wherein each pulsed light beam includes a beamlet of at least one light beam 116). Accordingly, a particular pulsed light beam in the plurality of pulsed light beams, such as a center pulsed light beam, may include a beamlet of each light beam 116 in the plurality of light beams 116. The particular pulsed light beam may thus include beamlets having various amounts of energy (e.g., based on the configuration of the plurality of optical amplifiers 110).

[0037] In addition, the pulsed laser 102, when configured to facilitate an incoherent beam combining condition of the plurality of light beams 116, can be operated in a burst mode, wherein beamlets of a particular pulsed beam are provided in a burst form (e.g., provided serially) (e.g., wherein each beamlet is temporally spaced a specific amount of time from a previous beamlet or a subsequent beamlet). For example, the pulsed laser 102 can provide N beamlets in a THz burst form (e.g., wherein the amount of time between consecutive beamlets can be less than or equal to 1 ps). In addition, because the plurality of fine OPD tuning elements 106, the plurality of coarse OPD tuning elements 108, and / or the fine and coarse OPD tuning elements 122 can be configured to finely and / or coarsely modify the length of the optical path 118 of the plurality of light beams 116, the burst can be tunable. For example, the burst may be a tunable THz burst (eg, when the fine tuning range and the coarse tuning range are from 0 to 299 μm), or may be a tunable GHz to THz burst (eg, when the fine tuning range and the coarse tuning range are from 0 to 300 mm), etc.

[0038] As mentioned above, Figure 1A-1F are provided as examples. Other examples may differ from those described in Figure 1A-1F As described.

[0039] Figure 2A-2D is a schematic diagram of an example 200 associated with a tunable burst mode (eg, a tunable THz burst mode) of a pulsed laser 202 (eg, in a manner similar to that described herein with respect to Figure 1A-1F The pulsed laser 102 described above may be configured in the same or similar manner). Figure 2A shows the configuration of the pulsed laser 202, Figure 2B shows the arrangement of the beams resulting from the splitting of the input beam by the beam splitting optics of the pulsed laser 202; Figure 2C shows an arrangement of pulsed beams of output beams produced by beam combining optics of pulsed laser 202; and Figure 2D The temporal relationship between the beamlets within a pulsed beam burst is shown.

[0040] like Figure 2A As shown, the pulsed laser 202 may include a beam splitting optical element 104, a plurality of fine and coarse OPD tuning elements 122 (e.g., a first fine and coarse OPD tuning element 122-1, a second fine and coarse OPD tuning element 122-2, and a third fine and coarse OPD tuning element 122-3), a plurality of optical amplifiers 110 (e.g., a first optical amplifier 110-1, a second optical amplifier 110-2, and a third optical amplifier 110-3), and a beam combining optical element 112 (e.g., in the manner described herein with respect to Figure 1A-1FThe beam splitting optical element 104 can be configured to split the input light beam 204 into a plurality of light beams 206 (e.g., a first light beam 206-1, shown as a dashed line; a second light beam 206-2, shown as a solid line; and a third light beam 206-3, shown as a dotted line), which are then transmitted via a plurality of light paths 208 (e.g., via a first light path 208-1, a second light path 208-2, and a third light path 208-3, not shown in FIG. 1 ). Figure 2A ) propagates to the beam combining optical element 112.

[0041] Figure 2B An example arrangement of a first light beam 206-1, a second light beam 206-2, and a third light beam 206-3 is shown (at a point after propagating away from the beam splitting optical element 104 via a plurality of light paths 208). Figure 2B As shown, the multiple beams may be arranged in a one-dimensional array (eg, vertical columns), although other arrangements may be used.

[0042] Each fine and coarse OPD tuning element 122 and each optical amplifier 110 may be disposed on an optical path 208 of the light beam 206. For example, a first fine and coarse OPD tuning element 122-1 and a first optical amplifier 110-1 may be disposed on a first optical path 208-1 of the first light beam 206-1, a second fine and coarse OPD tuning element 122-2 and a second optical amplifier 110-2 may be disposed on a second optical path 208-2 of the second light beam 206-2, and a third fine and coarse OPD tuning element 122-3 and a third optical amplifier 110-3 may be disposed on a third optical path. Each fine and coarse OPD tuning element 122 may be configured to modify the length of the optical path 208 of the light beam 206 on which the fine and coarse OPD tuning element 122 is disposed, such as described herein with respect to Figure 1A-1F Each optical amplifier 110 can be configured to amplify the optical power of a light beam 206 propagating via an optical path 208 on which the optical amplifier 110 is disposed, such as described herein with respect to Figure 1A-1F as described.

[0043] Accordingly, the plurality of light beams 206 may propagate to the beam combining optical element 112 via the optical path 208 (e.g., after each light beam 206 is modified by the fine and coarse OPD tuning elements 122 and the optical amplifier 110). Each light beam 206 may propagate to the beam combining optical element 112 at a particular time (e.g., because the pulsed laser 202 may be configured to facilitate an incoherent beam combining condition of the plurality of light beams 206, such as by controlling the length of the respective optical paths 208 of the plurality of light beams 206 using the plurality of fine and coarse OPD tuning elements 122). For example, the first light beam 206-1 may propagate to the beam combining optical element 112 at a first time, the second light beam 206-2 may propagate to the beam combining optical element 112 at a second time (e.g., after the first time), and the third light beam 206-3 may propagate to the beam combining optical element 112 at a third time (e.g., after the first time and the second time).

[0044] The beam combining optical element 112 may combine the plurality of light beams 116 into an output light beam 210. For example, the beam combining optical element 112 may separate each light beam 206 into a plurality of beamlets (e.g., three beamlets) to form a plurality of pulsed light beams 212 (where each pulsed light beam 212 includes a beamlet of at least one light beam 206). For example, the beam combining optical element 112 may separate the first light beam 206-1 into three beamlets respectively included in the first pulsed light beam 212-1, the second pulsed light beam 212-2, and the third pulsed light beam 212-3; may separate the second light beam 206-2 into three beamlets respectively included in the second pulsed light beam 212-2, the third pulsed light beam 212-3, and the fourth pulsed light beam 212-4; and may separate the third light beam 206-3 into three beamlets respectively included in the third pulsed light beam 212-3, the fourth pulsed light beam 212-4, and the fifth pulsed light beam 212-5. In this way, the first pulsed beam 212-1 may include one beamlet (e.g., the beamlet of the first beam 206-1, shown as a dotted line); the second pulsed beam 212-2 may include two beamlets (e.g., the beamlet of the first beam 206-1, shown as a dotted line, and the beamlet of the second beam 206-2, shown as a solid line); the third pulsed beam 212-3 may include three beamlets (e.g., the beamlet of the first beam 206-1, shown as a dotted line; the beamlet of the second beam 206-2, shown as a solid line; and the beamlet of the third beam 206-3, shown as a dotted line); the fourth pulsed beam 212-4 may include two beamlets (e.g., the beamlet of the second beam 206-2, shown as a solid line, and the beamlet of the third beam 206-3, shown as a dotted line); and the fifth pulsed beam 212-5 may include one beamlet (e.g., the beamlet of the third beam 206-3, shown as a dotted line).

[0045] Figure 2C An example arrangement of the plurality of pulsed beams 212 at a point after propagating away from the beam combining optical element 112 is shown. Figure 2C As shown, the first pulsed beam 212-1, the second pulsed beam 212-2, the third pulsed beam 212-3, the fourth pulsed beam 212-4 and the fifth pulsed beam 212-5 may be arranged in a one-dimensional array (eg, a vertical column), although other arrangements may also be used.

[0046] As described above, the first light beam 206-1 may be propagated to the beam combining optical element 112 at a first time, the second light beam 206-2 may be propagated to the beam combining optical element 112 at a second time, and the third light beam 206-3 may be propagated to the beam combining optical element 112 at a third time. Accordingly, the first pulsed light beam 212-1 may be provided as a single pulse associated with the first time (because the first pulsed light beam 212-1 includes a beamlet of the first light beam 206-1); the second pulsed light beam 212-2 may be provided as two pulses (e.g., in a burst form) associated with the first time and the second time (because the second pulsed light beam 212-2 includes the corresponding beamlets of the first light beam 206-1 and the second light beam 206-2); the third pulsed light beam 212-3 may be provided as three pulses (e.g., in a burst form) associated with the first time, the second time, and the third time (because the third pulsed beam 212-3 includes the first beam 206-1, the second beam 206-2 and the corresponding beamlets of the third beam 206-3); the fourth pulsed beam 212-4 can be provided as two pulses (for example, in a burst form) associated with the second time and the third time (because the fourth pulsed beam 212-4 includes the second beam 206-2 and the corresponding beamlets of the third beam 206-3); and the fifth pulsed beam 212-5 can be provided as a single pulse associated with the third time (because the fifth pulsed beam 212-5 includes the beamlet of the third beam 206-3).

[0047] It is worth noting that the pulsed light beam 212-3 may include a beamlet (e.g., in a burst) from each of the plurality of light beams 206. Figure 2D As shown, the pulsed light beam 212-3 may include a plurality of beamlets 214 (e.g., a first beamlet 214-1 from the first light beam 206-1, shown as a dashed curve; a second beamlet 214-2 from the second light beam 206-2, shown as a solid curve; and a third beamlet 214-3 from the third light beam 206-3, shown as a dotted curve) provided in a plurality of pulses 216 (shown as pulses 216-1 to 216-3). Figure 2DAs shown, because the pulsed laser 202 can be configured to facilitate an incoherent beam combining condition of the plurality of beams 206 (e.g., by controlling the lengths of the respective optical paths 208 of the plurality of beams 206 using the plurality of fine and coarse OPD tuning elements 122), the amount of time between consecutive beamlets 214 within a burst 216 can be less than or equal to 1 ps, and thus the pulsed laser 202 can be said to include a THz burst mode. Although the plurality of beamlets 214 are shown as having the same or similar amplitudes, each beamlet 214 can have a specific amplitude (e.g., based on the configuration of the corresponding optical amplifier 110), which can be different from other beamlets in the plurality of beamlets 214. Accordingly, the optical energy of the plurality of beamlets within the pulsed beam 212-3 can be said to be tunable.

[0048] Furthermore, because the lengths of the respective optical paths 208 of the plurality of light beams 206 can be modified using the plurality of fine and coarse OPD tuning elements 122, the pulsed laser 202 can be said to include a tunable THz burst mode (e.g., a burst that can be greater than or equal to a minimum value, such as 1 THz, 10 THz, or 50 THz, and can be less than a maximum value, such as 100 THz, 500 THz, 1000 THz, or 3000 THz). In some embodiments, the pulsed laser 202 can be said to include a tunable GHz to THz mode (e.g., a burst that can be greater than or equal to a minimum value, such as 1 GHz, 100 GHz, or 500 GHz, and can be less than a maximum value, such as 100 THz, 500 THz, 1000 THz, or 3000 THz).

[0049] As mentioned above, Figure 2A-2D are provided as examples. Other examples may differ from those described in Figure 2A-2D as described.

[0050] Figure 3A-3B is a schematic diagram of an example 300 associated with a tunable burst mode (eg, a tunable THz burst mode) of a pulsed laser (eg, configured in the same or similar manner as pulsed laser 102 and / or pulsed laser 202 described herein). Figure 3A An arrangement of light beams 302 resulting from the splitting of the input beam by beam splitting optics of a pulsed laser is shown. Figure 3B An arrangement of pulsed beams 304 of output beams produced by beam combining optics of a pulsed laser is shown.

[0051] Figure 3A An example arrangement of multiple beams 302 is shown (at a point after propagating away from the beam splitting optics of the pulsed laser via multiple optical paths, such as in the manner described herein with respect to Figure 1A-1F and Figure 2A-2D described in a similar manner). Figure 3A As shown, the plurality of light beams 302 may include a first light beam 302-1 to a ninth light beam 302-9. Figure 3A As shown, the plurality of light beams 302 may be arranged in a two-dimensional array (eg, a 3×3 square), although other arrangements may also be used.

[0052] Figure 3B An example arrangement of multiple pulsed beams 304 (e.g., output beams produced by a beam combining optic of a pulsed laser that combines multiple beams 302) at a point after propagation away from the beam combining optic is shown. Figure 3B As shown, the plurality of pulse beams 304 may include a first pulse beam 304-1 to a twenty-fifth pulse beam 304-25. Figure 3B As shown, the plurality of light beams 302 may be arranged in a two-dimensional array (eg, a 5×5 square), although other arrangements may also be used.

[0053] Notably, a central pulse beam 304 of the plurality of pulse beams 304, such as pulse beam 304-13, may include beamlets from each of the plurality of beams 302, such as in a burst (e.g., in a manner similar to that described elsewhere herein). Accordingly, the pulsed laser may be configured to facilitate an incoherent beam combining condition of the plurality of beams 302 (e.g., in a manner similar to that described elsewhere herein), and thus the amount of time between consecutive beamlets of the central pulse beam 304 (e.g., within a burst) may be less than or equal to 1 ps. In this manner, the pulsed laser may be said to include a THz burst mode.

[0054] As mentioned above, Figure 3A-3B are provided as examples. Other examples may differ from those described in Figure 3A-3B As described.

[0055] Figure 4A-4B is a schematic diagram of an example 400 associated with a tunable burst mode (eg, a tunable THz burst mode) of a pulsed laser (eg, configured in the same or similar manner as pulsed laser 102 and / or pulsed laser 202 described herein). Figure 4A An arrangement of light beams 402 resulting from the splitting of the input beam by beam splitting optics of a pulsed laser is shown. Figure 4B An arrangement of pulsed beams 304 of output beams produced by beam combining optics of a pulsed laser is shown.

[0056] Figure 4A An example arrangement of multiple beams 402 is shown (at a point after propagating away from the beam splitting optics of the pulsed laser via multiple optical paths, such as in the manner described herein with respect to Figure 1A-1F and Figure 2A-2Ddescribed in a similar manner). Figure 4A As shown, the plurality of light beams 402 may include a first light beam 402-1 to a seventh light beam 402-7. Figure 4A As shown, the plurality of beams 302 may be arranged in a two-dimensional array (eg, a 7-beam hexagonal array), although other arrangements may also be used.

[0057] Figure 4B An example arrangement of multiple pulsed beams 404 (e.g., output beams produced by a beam combining optic of a pulsed laser that combines multiple beams 402) at a point after propagation away from the beam combining optic is shown. Figure 4B As shown, the plurality of pulse beams 404 may include a first pulse beam 404-1 to a nineteenth pulse beam 404-19. Figure 4B As shown, the plurality of beams 402 may be arranged in a two-dimensional array (eg, a 19-beam hexagonal array), although other arrangements may also be used.

[0058] Notably, a central pulse beam 404 of the plurality of pulse beams 404, such as pulse beam 404-10, may include beamlets from each of the plurality of beams 402, such as in a burst (e.g., in a manner similar to that described elsewhere herein). Accordingly, the pulsed laser may be configured to facilitate an incoherent beam combining condition of the plurality of beams 402 (e.g., in a manner similar to that described elsewhere herein), and thus the amount of time between consecutive beamlets of the central pulse beam 404 (e.g., within a burst) may be less than or equal to 1 ps. In this manner, the pulsed laser may be said to include a THz burst mode.

[0059] As mentioned above, Figure 4A-4B are provided as examples. Other examples may differ from those described in Figure 4A-4B As described.

[0060] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. Modifications and variations may be made in light of the above disclosure, or may be obtained from the practice of the embodiments. In addition, any embodiment described herein may be combined, unless the foregoing disclosure explicitly provides reasons why one or more embodiments may not be combined.

[0061] Even though specific combinations of features are described in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of the various embodiments. In fact, many of these features can be combined in ways that are not specifically described in the claims and / or disclosed in the specification. Although each dependent claim listed below may only directly depend on one claim, the disclosure of the various embodiments includes the combination of each dependent claim with each other claim in the claim set. As used herein, a phrase referring to "at least one" in a list of items refers to any combination of those items, including single members. For example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination of multiple identical items.

[0062] Unless clearly described, any element, action or instruction used herein should not be interpreted as key or necessary. In addition, as used herein, the articles "one" and "an" are intended to include one or more projects, and can be used interchangeably with "one or more". Additionally, as used herein, the term "multiple" is intended to include two or more projects, and can be used interchangeably with "two or more". In addition, as used herein, the article "the" is intended to include one or more projects associated with the article "the", and can be used interchangeably with "one or more". In addition, as used herein, the term "set" is intended to include one or more projects (for example, a combination of related projects, unrelated projects or related and unrelated projects), and can be used interchangeably with "one or more". If there is only one project, phrase "only one" or similar language is used. In addition, as used herein, the terms "have", "have", "hold" etc. are intended to be open terms. In addition, unless otherwise expressly stated, the phrase "based on" is intended to mean "at least partially based on". In addition, as used herein, the term "or" is intended to be inclusive when used in a series and may be used interchangeably with "and / or" unless otherwise expressly stated (e.g., if used in conjunction with "either" or "only one"). In addition, for ease of description, spatially relative terms such as "below," "below," "above," "on," etc. may be used herein to describe the relationship of one element or feature to another element or feature shown in the figures. Spatially relative terms are intended to encompass different orientations of the device, equipment, and / or element in use or operation in addition to the orientation depicted in the figures. The device may be oriented in other ways (rotated 90 degrees or other orientations), and the spatially relative descriptors used herein may likewise be interpreted accordingly.

Claims

1. A tunable pulse burst mode laser comprising: beam splitting optics; Multiple optical path difference OPD tuning elements; multiple optical amplifiers; and Beam combining optics, wherein: The beam splitting optical element is configured to split an input light beam into a plurality of light beams, which will propagate from the beam splitting optical element to the beam combining optical element via a plurality of light paths, The plurality of OPD tuning elements are respectively disposed on the plurality of optical paths and are configured to modify the corresponding lengths of the plurality of optical paths, The plurality of optical amplifiers are respectively arranged on the plurality of optical paths and are configured to amplify the respective optical powers of the plurality of light beams, and The beam combining optical element is configured to combine the plurality of light beams into an output light beam comprising a plurality of pulsed light beams, wherein a specific pulse beam among the plurality of pulse beams comprises a plurality of fine beams respectively from the plurality of beams, and Wherein, the multiple thin light beams are provided in the form of terahertz (THz) bursts.

2. The tunable pulse burst mode laser according to claim 1, wherein: The beam splitting optical element comprises at least one of the following: Diffractive Optical Element DOE, Segmented mirror, or Traditional beam splitter.

3. The tunable pulse burst mode laser according to claim 1, wherein: The beam combining optical element comprises at least one of: Diffractive Optical Element DOE, Segmented mirror, or Traditional beam splitter.

4. The tunable pulse burst mode laser according to claim 1, wherein: The plurality of OPD tuning elements include a plurality of fine OPD tuning elements, Wherein, each of the plurality of fine OPD tuning elements is configured to modify the length of an optical path of the plurality of optical paths within a fine tuning range from 0 micrometers μm to 5 μm.

5. The tunable pulse burst mode laser according to claim 4, wherein: The fine OPD tuning element of the plurality of fine OPD tuning elements comprises at least one of the following: Micro-electromechanical systems MEMS mirrors, Liquid crystal on silicon (LCOS) optical elements, Piezoelectrically actuated optical elements, Optical elements with adjustable thickness, or Optical element with tunable refractive index.

6. The tunable pulse burst mode laser according to claim 1, wherein: The plurality of OPD tuning elements include a plurality of coarse OPD tuning elements, Wherein, each of the plurality of coarse OPD tuning elements is configured to modify a length of an optical path of the plurality of optical paths within a coarse tuning range from 5 micrometers μm to 299 μm.

7. The tunable pulse burst mode laser according to claim 6, wherein: A coarse OPD tuning element of the plurality of coarse OPD tuning elements comprises at least one of: Translation stage, or Piezoelectrically actuated optical elements.

8. The tunable pulse burst mode laser according to claim 1, wherein: the plurality of OPD tuning elements comprising a plurality of fine and coarse OPD tuning elements, Wherein each of the plurality of fine and coarse OPD tuning elements is configured to modify a length of an optical path of the plurality of optical paths within a coarse tuning range from 0 microns μm to 299 μm.

9. The tunable pulse burst mode laser according to claim 8, wherein: The fine and coarse OPD tuning elements of the plurality of fine and coarse OPD tuning elements include at least one of: Translation stage, or Micro-electromechanical systems MEMS mirrors, Liquid crystal on silicon (LCOS) optical elements, Piezoelectrically actuated optical elements, Optical elements with adjustable thickness, or Optical element with tunable refractive index.

10. The tunable pulse burst mode laser according to claim 1, wherein: the beam splitting optical element being configured to split the input beam into a first number of beams, and the beam combining optical element being configured to split each of the first number of beams into a second number of beamlets to form the output beam, Wherein, the first number is equal to the second number.

11. The tunable pulse burst mode laser according to claim 10, wherein: The specific pulse beam of the output beam includes a third number of beamlets, Wherein, the third number is equal to each of the first number and the second number.

12. The tunable pulse burst mode laser according to claim 11, wherein: The optical power of the specific pulsed light beam is equal to the total optical power of the output light beam divided by the third quantity.

13. A tunable pulse burst mode laser comprising: beam splitting optics; Multiple optical path difference OPD tuning elements; and Beam combining optics, wherein: The beam splitting optical element is configured to split an input light beam into a plurality of light beams, which will propagate from the beam splitting optical element to the beam combining optical element via a plurality of light paths, The plurality of OPD tuning elements are respectively arranged on the plurality of optical paths, and The beam combining optical element is configured to combine the plurality of light beams into an output light beam comprising a pulse light beam, the pulse light beam comprising a plurality of beamlets respectively from the plurality of light beams, and wherein the plurality of light beams are provided in a burst form, and The time between consecutive light beams in the burst is less than or equal to 1 picosecond (ps).

14. The tunable pulse burst mode laser according to claim 13, wherein: The burst is a tunable terahertz (THz) burst.

15. The tunable pulse burst mode laser according to claim 13, wherein: Each of the beam splitting optical element and the beam combining optical element comprises at least one of: Diffractive Optical Element DOE, Segmented mirror, Traditional beam splitter.

16. The tunable pulse burst mode laser according to claim 13, wherein: Each of the plurality of OPD tuning elements is configured to modify a length of an optical path of the plurality of optical paths within a tuning range from 0 micrometers μm to 299 μm.

17. The tunable pulse burst mode laser according to claim 16, wherein: The OPD tuning element of the plurality of OPD tuning elements comprises at least one of the following: Translation stage, or Micro-electromechanical systems MEMS mirrors, Liquid crystal on silicon (LCOS) optical elements, Piezoelectrically actuated optical elements, Optical elements with adjustable thickness, or Optical element with tunable refractive index.

18. A tunable pulse burst mode laser comprising: beam splitting optics; Multiple optical path difference OPD tuning elements; and Beam combining optics, wherein: The beam splitting optical element is configured to split the input beam into a plurality of beams, The plurality of OPD tuning elements are respectively arranged on a plurality of optical paths of the plurality of light beams, and The beam combining optical element is configured to combine the plurality of beams into an output beam comprising a pulsed beam comprising a plurality of beamlets, and The plurality of fine light beams are provided in the form of tunable terahertz (THz) bursts.

19. The tunable pulse burst mode laser according to claim 18, wherein: The amount of time between consecutive beamlets within the tunable THz burst is less than or equal to 1 picosecond (ps).

20. The tunable pulse burst mode laser of claim 18, wherein: Each of the plurality of OPD tuning elements is configured to modify a length of an optical path of the plurality of optical paths to allow an amount of time between consecutive beamlets within a tunable THz burst to be less than or equal to 1 picosecond (ps).

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