Laser device for selectively operating in two different modes

Abstract

A laser device is disclosed that is configured to selectively operate in two different modes of operation: in a first mode of operation, the laser device is configured to output femtosecond laser pulses; and in a second mode of operation, the laser device is configured to output nanosecond laser pulses.

Description

[Technical Field]

[0001] The present invention relates to the technical field of laser devices configured to operate in two different modes. [Background technology]

[0002] In some industrial applications (e.g., materials science, materials processing) and some medical applications (e.g., ophthalmology or genetics), multiple lasers (laser devices) are used to perform one or more tasks on a workpiece. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2008 / 0112041 Summary of the Invention [Problem to be solved by the invention]

[0004] Providing multiple lasers (laser devices) can be costly and require a complex setup. [Means for solving the problem]

[0005] The object of the present invention is to provide a simpler solution. This object is met by a laser device according to claim 1. Preferred embodiments of the invention are set forth in the dependent claims.

[0006] In a first aspect, a laser device is disclosed that is configured to selectively operate in two different modes of operation (i.e., a first mode of operation and a second mode of operation). In the first mode of operation, the laser device is configured to output femtosecond laser pulses. In the second mode of operation, the laser device is configured to output nanosecond laser pulses.

[0007] The femtosecond pulses can have durations in the range of 50 fs to 1000 fs (e.g., in the range of 300 fs to 450 fs). The femtosecond pulses can have average powers of 1 W to 1 kW, e.g., between 2 and 100 W (e.g., about 5 W). The femtosecond pulses can have peak powers higher than 100 kW, e.g., 1 to 10 GW or even 20 PW (petawatt) peak powers. The femtosecond pulses can have repetition rates as high as 1 MHz, e.g., in the range of 1 kHz to 1 MHz.

[0008] The nanosecond pulses can have durations in the range of 5 ns to 500 ns (e.g., in the range of 30 ns to 100 ns). The nanosecond pulses can have average powers up to 1 kW, e.g., between 1 and 100 W (e.g., 2 to 10 W). The nanosecond pulses can have peak powers of about 100 kW or more, e.g., 1 MW or more, e.g., 80 MW or more, or even 90 MW or more. The nanosecond pulses can have high repetition rates in the range of 1 kHz to 5 MHz (e.g., 1 MHz, 10 MHz, etc.). The laser device can be configured to selectively provide wide pulses in the ns range and relatively narrow pulses, such as pulses at least 1000 times narrower than ns range pulses.

[0009] The laser device can be configured to provide high average powers, such as up to 1 kW, for example, from 2 W to 100 W (e.g., 5 W), regardless of the mode of operation. The laser device can be configured to provide pulses at repetition rates up to 10 MHz, such as in the range of 1 kHz to 5 MHz (e.g., around 1 MHz), regardless of the mode of operation.

[0010] In some embodiments, a laser device may be configured with multiple components for generating and / or processing femtosecond and nanosecond laser pulses, at least some of which are used in both modes of operation. The multiple components may be arranged in free space such that light between the components propagates in free space within the laser device during operation of the laser device.

[0011] In some embodiments, the laser device may include an oscillator. In some embodiments, the laser device may include a pulse stretcher. In some embodiments, the laser device may include an amplifier. The amplifier may include a cavity. In some embodiments, the laser device may include a pulse compressor. In some embodiments, the laser device may include a controller.

[0012] In some embodiments, the laser device may include a modulator, which may be configured to operate as a shutter. In some embodiments, in the first mode of operation the amplifier may be configured to operate in an amplification mode to provide an amplified pulse.

[0013] In a first mode of operation, the pulse compressor may be configured to temporally compress the amplified pulse, thereby generating a femtosecond pulse. The compressor may be a dispersive compressor. The compressor may be a diffraction grating pair or a chirped volume Bragg grating. The compressor is enabled to temporally compress the pulse to a duration similar to that of the initial seed pulse. In a second mode of operation, the compressor may not significantly affect nanosecond pulses. For example, the compressor may have a temporal dispersion between 100 and 150 ps (e.g., 120 and 130 ps). When such dispersion is added to an ns pulse with a pulse width of, for example, 5 to 500 ns, the compression becomes negligible. Even if the compressor has a larger dispersion (e.g., about 1 to 2 ns), such dispersion is still insignificant for nanosecond pulses. The compressor may be disabled and / or bypassed in the second mode of operation.

[0014] The modulator, e.g., a shutter, may be configured to modulate the energy of the amplified pulses. The modulator may be configured to control the pulse emission. The modulator may be an acousto-optic modulator. The modulator may be an electro-optic modulator. The modulator is selected depending on the application of the laser device, i.e., the requirements of the energy and / or repetition frequency of the laser pulses. The modulator is configured to reduce the repetition frequency of the pulses.

[0015] In some embodiments, in the second operating mode, the amplifier may include a cavity configured to generate nanosecond pulses. This allows the amplifier to operate in a mode that does not require an external optical signal input to the amplifier. Rather, the amplifier is enabled to generate nanosecond pulses having high peak power, such as between 10 kW and 100 kW, depending on the repetition rate, by utilizing its cavity resonator, i.e., multiple passes of optical pulses through the cavity resonator. In the second operating mode, the amplifier is enabled to provide an average output power of up to 100 W. In the second operating mode, the amplifier is enabled to generate 5 ns to 500 ns pulses, e.g., 5 to 500 ns, e.g., 10 to 300 ns, e.g., approximately 150 ns. Optionally, in the second operating mode, pulses are provided by the amplifier at high power, and then only the repetition rate and / or wavelength may be manipulated. The pulse power and / or pulse energy may be modulated by a modulator, such as a processing shutter.

[0016] In some embodiments, the amplifier may be a regenerative amplifier. Regenerative amplifiers can be operated in different modes depending on the desired output pulse, its duration, peak power, and repetition rate. In a first mode of operation, the regenerative amplifier may be fed by a seed pulse to be amplified, while in a second mode of operation, the regenerative amplifier may operate in a laser oscillator mode. Regenerative amplifiers typically achieve amplification by multiple passes of an optical pulse through a laser gain medium (e.g., a solid-state medium). The gain medium is typically arranged within an optical cavity with an optical switch realized by an electro-optic modulator and a polarizer. The use of a regenerative amplifier is beneficial because it can be operated in different modes, providing high amplification of short pulses.

[0017] In some embodiments, when the laser device is operated in the second operating mode, nanosecond pulses are generated by the amplifier cavity using the cavity damping principle. The basic idea of ​​the cavity damping principle is to keep the optical losses of the amplifier cavity as low as possible for a certain period of time. This allows time for an intense optical pulse to accumulate within the cavity. This pulse can be extracted within one round-trip time of the cavity using a cavity damper, such as an acousto-optic modulator (AOM) or an electro-optic modulator (EOM) like a Pockels cell.

[0018] Alternatively, when operating the laser device in the second operating mode, nanosecond pulses can be generated by the amplifier cavity using the Q-switching principle. In this case, the intracavity losses are modulated, which changes the Q-factor of the amplifier cavity, resulting in nanosecond pulses. Furthermore, by combining the cavity damping technique with Q-switching, nanosecond pulses can also be generated by the amplifier cavity.

[0019] In some embodiments, the modulator may be located after the amplifier. The modulator may be an acousto-optic modulator (AOM) or an electro-optic modulator (EOM). The modulator may be configured to control pulse emission as well as modulate pulse energy. The modulator is capable of controlling both femtosecond and nanosecond pulses. The modulator may be located either before or after the compressor, regardless of the amplifier's operating mode. The modulator is capable of controlling adaptive peak power and repetition rate of the pulses.

[0020] In some embodiments, the laser device can further include an oscillator, such as a short-pulse oscillator, and a pulse stretcher. In a first mode of operation, the oscillator is configured to generate femtosecond pulses, such as seed pulses, in the femtosecond range. The oscillator can be a fiber oscillator or a free-space oscillator. The oscillator can incorporate an ytterbium-doped KYW active laser crystal. Other ytterbium-doped crystals, such as Yb:YAG, Yb:KGW, Yb:CALGO, and Yb:Lu2O3, can also be incorporated. The oscillator can generate pulses at a high repetition rate, such as 20 to 100 MHz, e.g., about 80 MHz. Alternatively, the oscillator can be configured to generate pulses in the GHz range. The oscillator can be positioned before the amplifier. The oscillator is configured to provide a seed pulse. In some embodiments, the seed pulse has a duration in the femtosecond range, such as about 150 fs to about 350 fs. The average power of the seed pulse may be relatively low, such as less than 500 mW, e.g., less than 300 mW. The peak power of the seed pulse may be in the range of 1 kW to 15 kW, such as about 5 kW to about 12 kW. The oscillator is enabled to provide pulses to the amplifier. The oscillator may be configured to provide femtosecond pulses. In the second mode of operation, the oscillator is disabled or blocked. The femtosecond pulses generated by the oscillator may be amplified before being output from the laser device.

[0021] The pulse stretcher is configured to generate a time-stretched pulse from a femtosecond pulse. The pulse is stretched, for example, to 100 ps or 1-2 ns. In particular, the pulse stretcher may be configured to generate a time-stretched pulse in the picosecond to nanosecond range. The pulse stretcher may also generate a chirped pulse. The pulse stretcher may include a dispersive element. The pulse stretcher may be a fiber Bragg grating (FBG), a chirped volume Bragg grating, a long fiber (e.g., a length of 10 m or more), or a grating-based stretcher such as a Martinez stretcher. The Martinez stretcher may include two lenses positioned between two diffraction gratings. The dispersion of the pulse stretcher can be adjusted by adjusting the distance between the diffraction grating and the lenses.

[0022] The pulse stretcher may be disposed between the oscillator and the amplifier, and in a first operating mode stretches pulses generated by the oscillator to provide stretched pulses to the amplifier. In some cases, the pulse stretcher may not affect the pulse repetition frequency. In a second operating mode, the pulse stretcher may be inactive. The pulse stretcher is beneficial because it reduces the peak power of the pulse, thereby avoiding detrimental effects in the amplifier receiving the stretched pulse.

[0023] The stretched pulse is typically amplified and then compressed. The pulse compressor may be an element with a dispersion opposite to that of the pulse stretcher, thereby removing chirp and compressing the pulse in time to a duration similar to that of the pulse input to the pulse stretcher.

[0024] In some embodiments, in a first operating mode, the amplifier can be configured to receive a time-stretched pulse and generate an amplified pulse from the time-stretched pulse. The long pulse duration of the stretched pulse reduces the peak power to a level that avoids detrimental effects in the amplifier gain medium. Preferably, the amplified pulse has a reduced repetition frequency compared to the repetition frequency of the time-stretched pulse. The repetition frequency may be reduced to the kHz range. An amplifier, such as a Pockels cell, which defines the round-trip number of the pulse within the amplifier, can be used to control the pulse repetition frequency. High pulse energy is achieved at a low repetition frequency. Typically, the repetition frequency of the amplified pulse is between 50 kHz and 1 MHz (e.g., 100 kHz and 500 kHz).

[0025] In some embodiments, the laser device further comprises an output switch configured to either direct the pulses directly to the output of the laser device or redirect the pulses for further optical processing, such as directing the pulses to a harmonic generation component. The output switch can be located after the modulator or after the pulse compressor.

[0026] In some embodiments, the laser device may include a harmonic generation component. The harmonic generation component may comprise one or more, e.g., two or more, nonlinear optical crystals, such as lithium triborate (LBO) and / or barium borate (BBO) crystals, configured to convert the pulses to second, third, fourth, etc. harmonics. As an example, if the fundamental wavelength is 1030 nm, the third harmonic is 343.3 nm, the fourth harmonic is 257.5 nm, and the fifth harmonic is 206 nm. Other examples are contemplated without departing from this disclosure. In the second mode of operation, the output switch may be configured to direct the nanosecond pulses to the harmonic generation component. The harmonic generation component may be configured to generate harmonics from the nanosecond pulses and output the generated harmonics. Harmonics may be generated by frequency conversion, such as sum frequency generation (SFG), second harmonic generation (SHG), third harmonic generation (THG), or fourth harmonic generation (FHG). The harmonic generation component is configured to change the center wavelength of the pulse. The changed pulse, typically of a lower wavelength compared to the initial seed pulse, may then be sent to the laser output. The laser output in this case may be the output of the harmonic generation component. The harmonic generation component may have multiple outputs for outputting pulses having different center wavelengths. Including a harmonic generation component in a laser device is useful for adding additional functionality to the laser device, such as generating different wavelengths. In some examples, the harmonic generation component is configured to convert pulses in the infrared (IR) range to the ultraviolet (UV) range. The UV range may be understood as wavelengths from about 200 nm to about 400 nm. In some examples, the harmonic generation component is configured to convert IR pulses to pulses in the green spectral range, such as the range from 495 nm to 570 nm. Two nonlinear crystals may be required to convert IR pulses to UV pulses. The harmonic generation component changes the pulse duration. Because the conversion efficiency is usually less than 100%, the harmonic generation component changes the average power of the pulse.

[0027] In some embodiments, the harmonic generating components are bypassed in the first or second operating modes. The harmonic generating components may be optimized differently for ns pulses compared to their configuration for fs pulses.

[0028] In some embodiments, the output switch may be synchronized with the oscillator. Coupling the output switch to the oscillator may synchronize the output of femtosecond pulses at the output switch with the generation of femtosecond pulses at the oscillator. The output switch may be electrically coupled to the oscillator. Synchronization may be established via an electronic controller. In a first mode of operation, the output switch may be configured to output amplified pulses at a fundamental wavelength, e.g., outputting amplified fs pulses with a center wavelength between about 1015 nm and about 1080 nm. In a second mode of operation, the output switch may be configured to disable the output of the fundamental wavelength and instead redirect the pulses to a harmonic generation component. The harmonic generation component may be configured to convert the fundamental wavelength to one or more harmonics using frequency conversion.

[0029] In some embodiments, the modulator, e.g., a shutter, may be synchronized with the oscillator and / or the output switch. The modulator may be coupled to the output switch and oscillator to control the emission of the femtosecond pulses and / or modulate the pulse energy of the femtosecond pulses. The modulator may be synchronized with the oscillator / switch by an electronic controller. The modulator may be electrically coupled to the output switch and oscillator via the electronic controller. Synchronization between the oscillator, modulator, and output switch is beneficial to the overall performance of the laser device and ensures the generation of high-quality pulses with high peak power. In some embodiments, the harmonic generation components may be synchronized with the amplifier and / or the oscillator.

[0030] In some embodiments, the laser device includes a controller, such as an electronic controller, configured to switch the laser device between a first mode of operation and a second mode of operation. The electronic controller is configured to disable components not used to generate pulses in either mode. The electronic controller is configured to ensure synchronous operation of various components that are part of the laser device. The electronic controller is configured to be user-operated to change the laser device's operating mode. User operation of the electronic controller is beneficial for ensuring easy operation of the laser device. The electronic controller is configured to be operated by an external controller, allowing the system to determine the laser device's operating mode and integrate the laser device into a system.

[0031] In some embodiments, a controller is electrically coupled or otherwise coupled to the amplifier to switch the operation of the amplifier between an amplification mode and a cavity dumping or Q-switching mode of operation. Having an amplifier with dual modes of operation allows for a laser device having two different modes of operation to be realized. Switching the operational mode of the amplifier also switches the operational mode of the laser device. The controller may be the same as the electronic control device configured to control the other components of the laser device, ensuring that all components are controlled simultaneously, thereby changing the operational mode of the laser device.

[0032] The electronic control device may be a mode selector operably connected to the laser components to define the laser's operating mode. The controller may be connected to a computer to control the laser's operating mode depending on the application the laser is being used in. The computer may further control pulse duration, repetition rate, center wavelength, etc.

[0033] In some embodiments, femtosecond pulses are generated by chirped pulse amplification (CPA) within a laser device. The use of chirped pulse amplification to generate femtosecond pulses is advantageous because this technique allows for pulse amplification to very high optical intensities while avoiding excessive nonlinear pulse distortion and optical damage. The amplified femtosecond pulses are generated from a chirped and time-stretched seed femtosecond pulse in a pulse stretcher before passing through the amplifier. The pulses are then sent to the amplifier. The long pulse duration reduces the peak power to a level that avoids undesirable nonlinear effects in the amplifier. Removing the chirp after amplification allows for the use of elements, such as compressors, configured to temporally compress the pulse. Chirped pulse amplification allows for pulses with a duration similar to that of the seed pulse but with significantly increased peak power.

[0034] In some embodiments, the femtosecond pulses have a central wavelength in the range of about 1015 nm to about 1080 nm, such as about 1030 nm. The femtosecond pulses may have a central wavelength of about 1050 nm. The central wavelength of the femtosecond pulses may be determined by the oscillator generating the seed pulse. The central wavelength of the femtosecond pulses may depend on the active laser medium used in the oscillator generating the seed pulse. The central wavelength of the femtosecond pulses may be affected by an amplifier.

[0035] In some embodiments, the nanosecond pulses have a center wavelength in the green or ultraviolet spectral range after passing through the harmonic generation component. The green spectral range can be understood as wavelengths from about 495 nm to about 570 nm. The ultraviolet range can be understood as wavelengths from about 200 nm to about 400 nm. The center wavelength of the nanosecond pulses may be defined by the conversion in the harmonic generation component. In some examples, the center wavelength of the nanosecond pulses may be in the range from about 900 nm to about 1100 nm, e.g., about 1030 nm or about 1050 nm. Having a laser device configured to provide pulses of many different wavelengths is beneficial because it allows for a variety of uses of the laser device in different fields.

[0036] In some embodiments, the central wavelength of the laser pulse can be adapted by the harmonic generation component. Both nanosecond and femtosecond pulses may be processed by the harmonic generation component. The harmonic generation component can be selected depending on the application of the laser device. Alternatively, the laser device may be configured with a nanosecond harmonic generation component suitable for converting nanosecond pulses and a femtosecond harmonic generation component suitable for converting femtosecond pulses. Depending on the operation mode of the laser device, one of the components is bypassed and the other is used for conversion.

[0037] In a second aspect, a medical system is disclosed that includes the laser device according to the first aspect. The medical system may further include a means for guiding a laser beam from the laser device to a patient. The means for guiding the laser beam may include various optical components. The system may further include a controller for controlling both the laser device and the means for guiding the laser beam. In some embodiments, the medical system includes an optical transmission fiber coupled to an output of the laser device. The optical transmission fiber may be suitable for guiding and transmitting femtosecond and / or nanosecond pulses generated by the laser device disclosed herein. The optical transmission fiber may be a microstructured fiber, such as a photonic crystal fiber. In some embodiments, the optical transmission fiber is selected from the group of index-guided photonic crystal fiber, photonic bandgap photonic crystal fiber, solid-core photonic crystal fiber, or hollow-core photonic crystal fiber.

[0038] In some embodiments, a medical system for use in an ophthalmic procedure is disclosed. Thus, the medical system may be an ophthalmic system. In some embodiments, a medical system for use in a surgical procedure is disclosed. The medical system may be an ophthalmic surgical system.

[0039] The above aspects, appended claims and / or examples disclosed herein above and below may be suitably combined with one another as would be apparent to a person skilled in the art. Additional features and advantages are disclosed in the following specification, claims, and drawings, and in part will become readily apparent to those skilled in the art or may be learned by practice of the present disclosure as set forth herein.

[0040] Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0041] [Figure 1] 1 illustrates an exemplary embodiment of a laser device according to the present disclosure. [Figure 2] 1 illustrates an exemplary embodiment of a laser device according to the present disclosure. [Figure 3] 1 illustrates an exemplary embodiment of a laser device operating in a first mode of operation. [Figure 4] 1 illustrates an exemplary embodiment of a laser device operating in a second mode of operation. [Figure 5] 1 illustrates yet another exemplary embodiment of a laser device according to the present disclosure. [Figure 6] 1 illustrates yet another exemplary embodiment of a laser device according to the present disclosure. [Figure 7] 1 illustrates yet another exemplary embodiment of a laser device according to the present disclosure. [Figure 8] 1 illustrates yet another exemplary embodiment of a laser device according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0042] 1 illustrates an exemplary embodiment of a laser device 2 according to the present disclosure. The laser device 2 is configured to selectively operate in two different modes of operation. In a first mode of operation, the laser device is configured to output femtosecond laser pulses 4. In a second mode of operation, the laser device is configured to output nanosecond laser pulses 6.

[0043] 2 illustrates a more detailed exemplary embodiment of a laser apparatus 2 according to the present disclosure. The laser apparatus 2 includes components for generating and / or processing femtosecond and nanosecond laser pulses, at least some of which are used in both modes of operation. In the embodiment illustrated in FIG. 2, the laser apparatus 2 includes an oscillator 8, a pulse stretcher 10, an amplifier 12, a pulse compressor 14, and a controller 16.

[0044] The oscillator 8 is enabled to generate a seed pulse, which may have a center wavelength in the range of about 1015 nm to about 1080 nm, such as about 1030 nm.

[0045] The controller 16 may be configured to switch the operating mode of the laser device 2 between a first operating mode and a second operating mode. In either mode, the electronic control device (electronic controller 16) is enabled to disable components not used in pulse generation. The electronic control device (16) is enabled to ensure synchronous operation of the various components that form part of the laser device 2. The electronic control device is user-operated, thereby enabling the operating mode of the laser device 2 to be changed. Having a user-operated electronic control device is beneficial to ensure easy operation of the laser device.

[0046] FIG. 3 illustrates an exemplary embodiment of a laser apparatus operating in a first operating mode. In the first operating mode, an oscillator 8 is configured to generate short pulses 80, such as femtosecond pulses, or picosecond pulses of less than 10 ps, ​​such as 1-2 ps pulses. The pulse repetition rate may be as high as 80 MHz or higher. A pulse stretcher 10 is configured to generate a time-stretched pulse 100 from the short pulse 80. The time-stretched pulse 100 may be in the picosecond or nanosecond range. The time-stretched pulse 100 is input to an amplifier 12. In the first operating mode, the amplifier 12 is configured to amplify the received pulse to output an amplified pulse 121. A controller 16 may control the amplifier 12 to operate in a standard amplification regime. The amplifier 12 may be a regenerative amplifier. The amplifier 12 may also reduce the repetition rate of the input pulse. Finally, the amplified pulse 121 is compressed in a pulse compressor 14. The pulse compressor 14 is configured to temporally compress the amplified pulse 121 to the femtosecond range, thereby generating a femtosecond laser pulse 4.

[0047] Femtosecond pulses 4 are generated by chirped pulse amplification in a laser device 2. The use of chirped pulse amplification to generate femtosecond pulses 4 is advantageous because this technique allows pulses to be amplified to very high optical intensities while avoiding excessive nonlinear pulse distortion and optical damage. The amplified femtosecond pulses 4 are generated from a seed femtosecond pulse 80 by chirping and time-stretching it in a pulse stretcher 10 before passing through an amplifier 12 to a much longer duration, e.g., ps or ns. The time-stretched pulses 100 are then sent to the amplifier 12. The longer pulse duration reduces the peak power to a level that avoids undesirable nonlinear effects in the amplifier 12. After amplification, a pulse compressor 14 temporally compresses the pulse by removing the chirp. The femtosecond (fs) pulses 4 have a duration similar to that of the seed pulse 80, while significantly increasing their peak power, as shown schematically in FIG. 3. Thus, in some embodiments, the laser device is configured to provide femtosecond pulses having a pulse duration similar to that of the seed pulse, and the peak power of the femtosecond pulses is higher than that of the seed pulse.

[0048] FIG. 4 illustrates an exemplary embodiment of the laser device 2 operating in a second operating mode. In the second operating mode, the oscillator 8 is blocked or disabled, which can be controlled via the controller 16. Naturally, the pulse stretcher 10 is also inactive because it has no input. In the second operating mode, the amplifier 12 is configured to include a cavity resonator configured to generate nanosecond pulses 122. Thus, in the second operating mode, the amplifier 12 can be controlled by the controller 16 to operate in a mode (laser oscillator mode) that does not require an external optical input. Rather, the amplifier 12 generates nanosecond pulses 122 having high peak power (e.g., 10 kW to 100 kW) by utilizing its cavity resonator, i.e., multiple passes of an optical pulse through the cavity resonator. In the second operating mode, the nanosecond pulses 122 are generated by the amplifier's cavity resonator using the cavity damping principle. Alternatively, when operating the laser device 2 in the second operating mode, the nanosecond pulses 122 can be generated by the amplifier cavity resonator using the Q-switching principle. Furthermore, by combining the cavity damping technique with Q-switching, it is possible to generate nanosecond pulses by the amplifier cavity resonator. In the second operating mode, the pulse compressor 14 has a negligible effect on the relatively long nanosecond pulses 122. Nanosecond laser pulses 6 are thus output from the laser device 2.

[0049] FIG. 5 illustrates yet another exemplary embodiment of a laser device 2 according to the present disclosure. The laser device 2 includes all of the components detailed in connection with FIGS. 2-4 and further includes a modulator 18. The modulator 18 may be configured to operate as a shutter. The modulator 18 may be located after the pulse compressor 14 (as shown in FIG. 5). Alternatively, the modulator 18 may be coupled into the system after the amplifier 12. The placement of the modulator is independent of the operating mode of the amplifier 12. The modulator may be an acousto-optic or electro-optic modulator. The modulator may be configured to control pulse emission as well as modulate pulse energy. The modulator may be capable of controlling both femtosecond and nanosecond pulses. The modulator may be controlled to adapt the peak power and repetition rate of the pulses.

[0050] 6 illustrates yet another exemplary embodiment of a laser apparatus 2 according to the present disclosure. Laser apparatus 2 includes all of the components detailed in connection with FIGS. 2-5, and further includes an output switch 20. Output switch 20 may be coupled to modulator 18. In some embodiments, modulator 18 may be omitted, and therefore output switch 20 may be coupled to pulse compressor 14. Output switch 20 may have two separate outputs, one for outputting femtosecond pulses and one for outputting nanosecond pulses.

[0051] FIG. 7 illustrates yet another exemplary embodiment of a laser device 2 according to the present disclosure. Laser device 2 includes all of the components detailed above with respect to FIGS. 2-6, and further includes a harmonic generation component 22. Harmonic generation component 22 may be coupled to one of the outputs of output switch 20, e.g., the nanosecond output. In some embodiments, modulator 18 and output switch 20 may be omitted, and thus harmonic generation component 22 may be coupled directly to pulse compressor 14. Harmonic generation component 22 may have two separate outputs. One of the two outputs is for outputting pulses in the UV range, and the other is for outputting pulses in the green spectral range. The green spectral range may be from about 495 nm to about 570 nm.

[0052] 8 illustrates yet another exemplary embodiment of a laser apparatus 2 according to the present disclosure. In this embodiment, an amplifier 12 is coupled to an oscillator 8 via a controller 16 to ensure clean picking into and out of the amplifier 12. An output switch 20 is electrically coupled to the amplifier 12 to synchronize output pulses at the output switch 20 with the generation of seed pulses 80 at the oscillator 8. Additionally, a modulator 18 can be electrically coupled to the output switch 20 and the amplifier 12 to control the emission of the output pulses and / or modulate the pulse energy of the output pulses.

[0053] The terms used herein are for the purpose of describing particular aspects only and are not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that as used herein, the terms "comprises," "comprising," "includes," and / or "including" specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0054] Relative terms such as "below" or "above," or "upper" or "lower" may be used herein to describe the relationship of one value to another. When an element is referred to as being "connected" or "coupled" to another element, it will be understood that the element may be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0055] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Furthermore, it will be understood that terms used herein should be interpreted as having a meaning consistent with the meaning in the context of the present specification and related art, and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0056] It is to be understood that the present disclosure is not limited to the embodiments described above and illustrated in the drawings, but rather, those skilled in the art will recognize that many changes and modifications may be made within the scope of this disclosure and the appended claims. In the drawings and specification, embodiments are disclosed that are for purposes of illustration only, and not for purposes of limitation, the scope of the inventive concept being defined in the following claims. [Explanation of symbols]

[0057] 2...Laser device. 4...Femtosecond pulse. 6...Nanosecond pulse. 8...Oscillator. 80...Short pulse generated by the oscillator. 10...Pulse stretcher. 100...Time-stretched pulse. 12...Amplifier. 121...Amplified pulse. 122...Amplified ns (nanosecond) pulse. 14...Pulse compressor. 16...Controller. 18...Modulator. 20...Output switch. 22...Harmonic generating component.

Claims

1. 1. A laser apparatus comprising an oscillator, a pulse stretcher, an amplifier, and a pulse compressor, wherein the amplifier comprises a cavity resonator, the laser apparatus configured to selectively operate in two different operating modes, the two operating modes comprising: a first mode of operation in which the laser apparatus is configured to output femtosecond laser pulses, wherein in the first mode of operation the oscillator is configured to generate seed pulses in the femtosecond range, the pulse stretcher is configured to generate time-stretched pulses from the seed pulses, the amplifier is configured to operate in an amplification mode to provide amplified pulses, and the pulse compressor is configured to time-compress the amplified pulses to generate femtosecond pulses; and a second mode of operation in which the laser device is configured to output nanosecond laser pulses, wherein the amplifier cavity is configured to generate nanosecond pulses; and A laser device comprising:

2. the laser device comprising a plurality of components for generating and / or processing the femtosecond laser pulses and the nanosecond laser pulses; At least some of the components are used in both of the operating modes.

2. The laser device according to claim 1.

3. The plurality of components are disposed in free space; the light between the components propagates in the free space within the laser device; 3. The laser device according to claim 1 or 2.

4. the generated time-stretched pulses are in the picosecond to nanosecond range; The laser device according to any one of claims 1 to 3.

5. the nanosecond pulses are generated by the cavity resonator of the amplifier using the principle of cavity damping or Q-switching; The laser device according to any one of claims 1 to 4.

6. the amplifier is a regenerative amplifier; The laser device according to any one of claims 1 to 5.

7. the oscillator is configured to generate seed pulses having a repetition frequency between 20 MHz and 100 MHz; The laser device according to any one of claims 1 to 6.

8. the seed pulse is a short pulse having a duration of about 150 fs to 300 fs; The laser device according to any one of claims 1 to 7.

9. the femtosecond laser pulse has a duration in the range of 50 fs to 1000 fs, for example in the range of 200 fs to 450 fs; The laser device according to any one of claims 1 to 8.

10. the laser device further comprises a modulator; the modulator is configured to modulate the energy of the amplified pulses. The laser device according to any one of claims 1 to 9.

11. the modulator is further configured to operate as a shutter; The laser device according to claim 10.

12. the modulator is an acousto-optical modulator (AOM) or an electro-optical modulator (EOM) placed after the amplifier; 12. The laser device according to claim 10 or 11.

13. In the first mode of operation, the amplifier is configured to receive the time-stretched pulse and generate the amplified pulse from the time-stretched pulse. The laser device according to any one of claims 1 to 12.

14. the amplified pulses have a reduced repetition frequency relative to the repetition frequency of the time-stretched pulses.

14. The laser device according to claim 13.

15. the pulse compressor is configured to temporally compress the amplified pulse to a duration similar to that of the seed pulse. The laser device according to any one of claims 1 to 14.

16. The laser device further comprises a harmonic generating component and an output switch. The laser device according to any one of claims 1 to 15.

17. in the second mode of operation, the output switch is configured to direct the nanosecond pulses to the harmonic generating component; the harmonic generating component is configured to generate and output harmonics from the nanosecond pulses; 17. The laser device of claim 16.

18. the harmonic generating component is bypassed or disabled in the first mode of operation or the second mode of operation; 18. The laser device according to claim 16 or 17.

19. the central wavelength of the laser pulse is adapted by the harmonic generating component; The laser device according to any one of claims 16 to 18.

20. the output switch is coupled, e.g., electrically coupled, to the oscillator to synchronize the output of the femtosecond pulses at the output switch with the generation of the femtosecond pulses at the oscillator; The laser device according to any one of claims 16 to 19.

21. a modulator coupled to the output switch and the oscillator for controlling emission of the femtosecond pulses and / or modulating pulse energy of the femtosecond pulses. The laser device according to any one of claims 16 to 20.

22. the laser device comprising a controller, such as an electronic controller, configured to switch the operating mode of the laser device between the first operating mode and the second operating mode. The laser device according to any one of claims 1 to 21.

23. the controller is coupled, e.g., electrically coupled, to the amplifier to switch operation of the amplifier between an amplification mode and a cavity damping or Q-switching mode of operation; 23. The laser device of claim 22.

24. the femtosecond pulses are generated by chirped pulse amplification in the laser device; The laser device according to any one of claims 1 to 23.

25. The femtosecond pulse has a central wavelength in the range of 1015 nm to 1080 nm, for example, about 1030 nm. The laser device according to any one of claims 1 to 24.

26. the nanosecond pulses have a center wavelength in the range of about 495 nm to about 570 nm or in the range of about 200 nm to about 400 nm; The laser device according to any one of claims 1 to 25.

27. the pulse stretcher is selected from the group of a fiber Bragg grating, a chirped volume Bragg grating, or a grating-based stretcher; The laser device according to any one of claims 1 to 26.

28. the oscillator, the pulse stretcher, the amplifier, and the pulse compressor are arranged as components in free space; During use of the laser device, light between the components propagates in free space. The laser device according to any one of claims 1 to 27.

29. A medical system comprising the laser device according to any one of claims 1 to 28, the medical system is an ophthalmology system; Healthcare system.

30. the medical system further comprises an optical transmission fiber coupled to an output of the laser device; the optical transmission fiber is configured to guide femtosecond and / or nanosecond pulses generated by the laser device; 30. The medical system of claim 29.

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