System for real-time laser power monitoring

Abstract

The present disclosure relates generally to systems and methods for laser power measurement, and more particularly to systems and methods for laser power measurement in a sterile operating environment. In certain embodiments described herein, power measurements are performed with two laser sources: 1) a first laser source configured to generate a first laser beam (treatment laser); and 2) a second laser source configured to generate a second laser beam (test laser). The first laser beam generates bubbles in a test material (e.g., water, brine, equilibrium salt solution, gel, etc.), and the second laser beam is reflected back, where the reflected portion of the second laser beam is measured to determine the lifetime of the bubbles and associate lifetime measurements with power measurements based on a correlation curve.

Description

Background Art

[0001] In order to prepare a surgical laser system for surgery, all of the components of the surgical laser system (e.g., a surgical console with a laser source, a handpiece, consumables, and optical fibers) must be assembled together. Proper assembly allows for efficient transmission of laser light from the laser source all the way to the distal fiber tip. Incomplete and / or incorrect assembly or misalignment of components during use may result in a lack of sufficient radiation at the fiber tip, and therefore, a lack of efficiency. Furthermore, while the power at the laser source may be known, the power level at the fiber tip may be unknown due to inherent variability in the optical connections of the different components of the surgical laser system during assembly or throughout use.

[0002] Conventional systems require the use of a power meter connected to the surgical laser system to measure the power level of the delivered laser light. Typically, the power level of the laser light delivered by the surgical laser system is measured prior to the surgical procedure. However, because power meters are non-sterile devices, using them in the operating room environment is cumbersome and time-consuming, as they must be carefully handled and isolated to maintain sterility and thus ensure patient safety. Furthermore, because conventional test systems are non-sterile, their use to verify laser power delivery during surgery is impossible. Summary of the Invention

[0003] The present disclosure relates to systems and methods for performing laser power measurements in a sterile operating environment.

[0004] In certain embodiments, laser power measurement is performed by a system including first and second laser sources, an optical fiber, and an optical detector. The first and second laser sources generate first and second laser beams, respectively. The optical fiber is configured to receive the first and second laser beams and direct them toward a test material. The first laser beam forms a bubble in the test material. A portion of the second laser beam is reflected from the interface between the optical fiber and the test material back into the optical fiber. The optical detector receives the reflected portion and determines the power level of the first laser beam based on the reflected portion of the second laser beam. This system allows for sterile power level determination.

[0005] In certain embodiments, a method is provided. The method includes generating a first laser beam by a first laser source. The method also includes generating a second laser beam by a second laser source. The method also includes receiving the first laser beam from the first laser source by an optical fiber. The method also includes directing the first laser beam by the optical fiber to a test material to form a bubble in the test material. The method also includes receiving a second laser beam from the second laser source at the optical fiber. The method also includes directing the second laser beam by the optical fiber to the test material. The method also includes receiving a reflected portion of the second laser beam from a distal end of the optical fiber and the bubble at the optical fiber. The method also includes directing the reflected portion of the second laser beam to an optical detector by the optical fiber. The method also includes receiving the reflected portion of the second laser beam from the optical fiber at the optical detector. The method also includes determining, by the optical detector, a power level of the first laser beam based on a duration of a change in the reflected portion of the second laser beam received at the optical detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] In order to enable a detailed understanding of the implementation of the above-mentioned features of the present disclosure, the present disclosure briefly summarized above will be described in more detail with reference to embodiments (some of which are shown in the accompanying drawings). However, it should be noted that the drawings only illustrate exemplary embodiments and are therefore not to be considered as limiting the scope thereof, and other equally effective embodiments may be allowed.

[0007] Figure 1A An exemplary system for performing laser power measurements according to certain embodiments of the present disclosure is presented.

[0008] Figure 1B Some embodiments of the present disclosure are shown Figure 1A Another arrangement of the exemplary system.

[0009] Figure 2 An exemplary method of performing laser power measurements according to certain embodiments of the present disclosure is presented.

[0010] Figures 3A to 3F Bubble development during laser power measurement is demonstrated according to certain embodiments of the present disclosure.

[0011] Figures 4A to 4B A graph showing a reflected portion of laser light according to certain embodiments of the present disclosure.

[0012] Figure 5 A curve showing the dependency of the back-reflected pulse width of the second laser on the laser power of the first laser according to certain embodiments of the present disclosure is shown.

[0013] Figure 6 A schematic diagram of a surgical console and its components according to certain embodiments of the present disclosure is shown.

[0014] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. DETAILED DESCRIPTION

[0015] The present disclosure relates generally to systems and methods for laser power measurement, and more particularly to systems and methods for performing laser power measurement in an operating environment, such as a sterile surgical operating environment.

[0016] Conventional systems require the use of a power meter to measure the power of the laser beam delivered from the working end of an optical fiber. However, because power meters are typically non-sterile devices, using a power meter in an operating room environment is cumbersome and time-consuming when attempting to maintain sterility to ensure patient safety. Further, due to the non-sterile nature of the power meter, the power level of the laser beam transmitted by the surgical laser system is typically measured only before a surgical procedure is performed. However, it is important to monitor the power of the laser beam delivered from the working end of an optical fiber throughout the entire process of performing a surgical procedure. Accordingly, embodiments of the present disclosure provide systems and methods that enable efficient laser power measurement before, during, and after a surgical procedure in a sterile operating environment.

[0017] In certain embodiments described herein, power measurement of a surgical laser system is performed using two laser sources: 1) a first laser source configured to generate a first laser beam (a "therapeutic" laser beam, such as an infrared (IR) laser beam); and 2) a second laser source configured to generate a second laser beam (a "test" laser beam, such as a visible light laser beam). Before or during a surgical procedure, the first and second laser beams can be propagated into a test material (e.g., water, saline, a balanced salt solution, a gel, etc.) to measure or monitor the power level of the first laser beam generated by the first laser source. The first laser beam, while propagating into the test material, creates a transient vapor bubble in the test material that can change the portion of the second laser beam that is reflected back into the surgical laser system. The duration of the change in the reflected portion of the second laser beam can then be optically measured to determine the lifetime of the vapor bubble, which can be correlated to the laser power value based on one or more correlation curves.

[0018] Laser power measurement using back reflection of the second laser beam allows for efficient testing in a sterile environment, even during surgical procedures, without the need for non-sterile equipment such as power meters. Testing of laser power levels can help identify equipment issues, including improper assembly, component failure, misalignment due to movement or use before or during surgical procedures, and the like. Thus, the methods and systems described herein not only enable real-time testing during surgical procedures, but also improve the overall safety of surgical procedures by reducing the risk of introducing contaminants.

[0019] Figure 1A A system 100 for performing laser power measurement according to certain embodiments of the present disclosure is shown. The system 100 includes a surgical laser system 101 that can be operably coupled to and / or in communication with a surgical console, such as a surgical console used for ophthalmic surgical procedures. The surgical laser system 101 includes a first laser source 102 configured to generate a first laser beam 104 and, in certain embodiments, a second laser source 106 configured to generate a second laser beam 108. Generally, the system 100 enables real-time measurement of the power of the first laser beam 104 generated by the first laser source 102 of the surgical laser system 101.

[0020] In some embodiments, the first laser source 102 is a therapeutic laser source configured to generate a first laser beam 104 for treating a patient. The first laser beam 104 can be used to cut and / or emulsify material during a surgical procedure. For example, the first laser beam 104 can be used as a therapeutic beam for performing various functions during an ophthalmic surgical procedure (e.g., a vitreoretinal procedure, glaucoma surgery, cataract surgery, etc.).

[0021] In some embodiments, the first laser beam 104 generated by the first laser source 102 is an ultraviolet ("UV") (<350 nm) (nanometer) laser. In some embodiments, the first laser beam 104 is an infrared ("IR") (780 nm to 4000 nm) laser, such as a mid-IR laser. In some embodiments, the first laser beam 104 is an argon blue-green laser (488 nm), a neodymium-doped yttrium aluminum garnet (Nd-YAG) laser (532 nm) (such as a frequency-doubled Nd-YAG laser), a krypton red laser (647 nm), or any other suitable type of laser for ophthalmic surgery. In some embodiments, the first laser beam 104 has a wavelength of approximately 500 nm.

[0022] In some embodiments, the first laser source 102 can generate and propagate a first laser beam 104 having a pulse frequency in the range of about 100 hertz (Hz) to 10 kilohertz (kHz). In some embodiments, the first laser source 102 can generate and propagate a first laser beam 104 having a pulse frequency in the range of about 10 kilohertz (kHz) to about 500 kHz, or between about 1 kHz and about 1500 Hz. Other pulse frequency ranges are also contemplated. In some examples, the first laser source 102 generates a nanosecond, picosecond, or femtosecond first laser beam 104. In some embodiments, the first laser source 102 is a continuous wave (CW) laser source that can be switched to a pulse mode during a calibration procedure.

[0023] Now return to Figure 1A In some embodiments, the surgical laser system 101 further includes a second laser source 106 configured to generate a second laser beam 108. In some embodiments, the second laser beam 108 can serve as a test laser beam for measuring the power level of the system 100. In some embodiments, the second laser beam 108 can be configured to further serve as an illumination source for the surgical site for aiming, etc.

[0024] In some embodiments, the second laser beam 108 generated by the second laser source 106 is a visible light (380 nm to 780 nm) laser or an IR (780 nm to 1000 nm) laser. For example, in some embodiments, the second laser beam 108 comprises a 640 nm laser. However, other spectra / ranges (e.g., 400 nm to 4 μm) are further contemplated for the second laser beam 108.

[0025] In some embodiments, the second laser source 106 can generate and transmit a second laser beam 108 having a pulse frequency in the range of about 100 hertz (Hz) to 10 kilohertz (kHz). In some embodiments, the second laser source 106 can generate and transmit a second laser beam 108 having a pulse frequency in the range of about 10 kilohertz (kHz) to about 5 MHz, or between about 1 kHz and about 1500 Hz. Other pulse frequency ranges are also contemplated. In some examples, the second laser source 106 generates a nanosecond, picosecond, or femtosecond second laser beam 108. In some embodiments, the second laser source 106 can generate a continuous, coherent, or semi-continuous second laser beam 108. For example, the second laser source 106 can generate a low-power continuous wave second laser beam 108.

[0026] In some embodiments, first laser beam 104 and second laser beam 108 may be generated by a single laser source of surgical laser system 101 that is configured to generate two or more types of laser beams or to generate laser beams with different characteristics. For example, in some embodiments, first laser beam 104 and second laser beam 108 may be generated by first laser source 102. In some other embodiments, first laser beam 104 and second laser beam 108 may be generated by second laser source 106.

[0027] System 100 further includes an optical fiber 110 having a proximal end 113 configured to be removably coupled to port 130 of surgical laser system 101. Optical fiber 110 can be configured to proximally receive and distally propagate both first and second laser beams 104, 108 generated by first and second laser sources 102, 106, respectively, which can be positioned near proximal end 113 of optical fiber 110. Optical fiber 110 can comprise any suitable type of optical fiber configured to transmit optical energy along its length. In some embodiments, optical fiber 110 can be fabricated at least in part from germanium oxide-based glass, sapphire, fluoride, zirconium fluoride, and / or silica. Optical fiber 110 can comprise a single material, a blend of multiple materials, have distinct regions of different materials, and the like. However, any suitable material or space for efficiently propagating laser beams 104 and 108 is contemplated. Optical fiber 110 can be at least partially clad, single-clad, double-clad, multi-clad, or unclad. In embodiments having a cladding, the cladding can be concentric with the core or cores of the optical fiber 110. In some embodiments, the first laser beam 104 and / or the second laser beam 108 can propagate through the optical fiber 110 via the cladding.

[0028] In some embodiments, optical fiber 110 has a single-core structure. In such embodiments, first laser beam 104 and second laser beam 108 can propagate along the same core of optical fiber 110. In other embodiments, optical fiber 110 has a multi-core structure. In such embodiments, first laser beam 104 and second laser beam 108 can propagate along the same core or different cores of optical fiber 110.

[0029] Generally, optical fiber 110 can be rigid or flexible. In some embodiments, optical fiber 110 can be straight or tapered. In some embodiments, optical fiber 110 has a diameter between about 100 micrometers (μm) and about 400 μm, such as between about 100 μm and about 300 μm, such as between about 100 μm and about 200 μm, such as between about 200 μm and about 400 μm, such as between about 200 μm and about 300 μm, such as between about 300 μm and about 400 μm. In some embodiments, optical fiber 110 can have different regions having similar or different geometric shapes. In such embodiments, the different regions can include one or more optical fiber segments butt-jointed to each other.

[0030] The optical fiber 110 can also be configured to distally receive and proximally propagate a reflected portion 120 of the second laser beam 108 that is reflected by the distal end 115 of the optical fiber 110 and reflected back into the optical fiber during performance of the power level measurement. The reflected portion 120 can travel through the optical fiber 110 in an opposite direction along the same core of the optical fiber 110 as at least one of the first laser beam 104 or the second laser beam 108 that propagates through the optical fiber 110, or along a different core.

[0031] In some embodiments, optical fiber 110 includes an optical fiber tip 114 disposed at a distal end 115 of optical fiber 110, opposite first laser source 102 and / or second laser source 106. Generally, first laser beam 104 and second laser beam 108 can be distally transmitted (i.e., emitted) from optical fiber tip 114 after propagating through optical fiber 110. Optical fiber tip 114 can be constructed from a similar or different configuration than another portion of optical fiber 110. For example, optical fiber tip 114 can differ from another portion of optical fiber 110 in terms of material, material properties, optical properties, geometry, etc. For example, optical fiber tip 114 can be rigid, while another portion of optical fiber 110 can include a flexible portion to allow positioning of optical fiber 114 relative to test material 112 or a surgical site. In some embodiments, optical fiber tip 114 includes a lens or window to facilitate distal transmission of first laser beam 104 and second laser beam 108 from optical fiber 110. In some embodiments, the lens or window can include sapphire. In some embodiments, the fiber tip 114 is configured to be disposed within or integrated with a handpiece of a surgical tool (e.g., an ophthalmic surgical laser probe). In some embodiments, the material of the fiber tip 114 is selected to be sufficiently strong to withstand the impact of repeated expansion and collapse of the bubble and / or to not chemically interact with the test material 112. An example of such a material includes sapphire.

[0032] In some embodiments, the optical fiber 110 and / or the system 100 may further include one or more optical elements configured to direct, redirect, filter, polarize, focus, collimate, split, or otherwise manipulate the first laser beam 104, the second laser beam 108, and / or the reflected portion 120 of the second laser beam 108. For example, Figure 1A , a first dichroic mirror 116 and a second dichroic mirror 118 are depicted. Generally, the dichroic mirrors 116 and 118 can facilitate reflection or transmission of the laser beam, depending on the wavelength of the laser beam. Figure 1A , first dichroic mirror 116 is depicted as facilitating transmission of first laser beam 104 and redirecting (e.g., reflecting) second laser beam 108 into optical fiber 110, while also facilitating redirecting a proximally traveling reflected portion 120 of second laser beam 108 toward second dichroic mirror 118. Second dichroic mirror 118 then redirects reflected portion 120 to optical detector 122 (or any suitable type of signal detector).

[0033] exist Figure 1A In the illustrated embodiment, a focusing lens 121 is also shown. The focusing lens 121 can be configured to focus at least one of the first laser beam 104 or the second laser beam 108 onto the optical fiber 110 at or through the port 130. For example, the focusing lens 121 can be configured to focus at least one of the first laser beam 104 or the second laser beam 108 onto the core of the optical fiber 110.

[0034] The system 100 further includes an optical detector 122 configured to receive the reflected portion 120 and generate an optical detector output based on the reflected portion 120. In some embodiments, the optical fiber 110 is configured to guide the reflected portion 120 of the second laser beam 108 to the optical detector 122 indirectly (e.g., via an air gap or other gap). In other embodiments, the optical fiber 110 can guide the second laser beam 108 to the optical detector 122 by direct contact transmission. The optical detector 122 can include a sensor 124 (e.g., a photodiode or other energy-sensitive detector element) that can detect the reflected portion 120 of the second laser beam 108 incident on the optical detector 122 and further generate an optical detector output.

[0035] In some embodiments, the optical detector output can be electrically amplified. In other embodiments, the optical detector output can be passed through a high pass filter to separate the transient back reflection signal from the direct current (DC) baseline, or a high pass filter can be used before or after the amplifier or between amplifier stages.

[0036] The optical detector 122 is coupled to a controller 126 that is configured to receive and analyze the optical detector output from the optical detector 122 corresponding to the detected reflected portion 120 and determine various metrics / characteristics of the reflected portion 120. Such metrics / characteristics of the reflected portion 120 are utilized to determine the power level of the laser light generated by at least the first laser source 102 at the fiber tip 114, as described in further detail below. Note that although the optical detector 122 and the controller 126 are Figure 1A 101 , the optical detector 122 and the controller 126 may be separate components operably coupled to the surgical laser system 101 , such as components of a surgical console operably coupled to the surgical laser system 101 .

[0037] System 100 may also include or be used in combination with a test material 112, with optical fiber 110 configured to direct first laser beam 104 and second laser beam 108 into the test material for performing power level measurements on first laser beam 104. In some embodiments, during use, optical fiber 110 may be positioned so as to be at least partially disposed within test material 112. In other embodiments, during use, optical fiber 110 may be positioned so as to only contact the surface of test material 112. Optical fiber 110 is configured to transmit first laser beam 104 and second laser beam 108 from optical fiber 110 into test material 112. In some embodiments, test material 112 may include a liquid, such as water, saline, balanced salt solution (BSS), etc. In some embodiments, test material 112 may include a viscoelastic material. Other examples may include liquid, semi-liquid, and / or semi-solid materials that form transient bubbles when laser energy is delivered to the test material. In some embodiments, test material 112 is a disposable or single-use material. In some embodiments, test material 112 may be a reusable or multi-use material.

[0038] To measure the power level of the laser light generated by the first laser source 102, an optical fiber tip 114 is placed in or near the test material 112, and the first laser source 102 is activated to generate a first laser beam 104. The first laser beam 104 is received at the proximal end of the optical fiber 110 and propagates distally through the optical fiber 110 to be transmitted from the optical fiber tip 114 into the test material 112. When the test material 112 receives the first laser beam 104, the thermal energy of the first laser beam 104 vaporizes or otherwise changes state or form in the test material 112, thereby generating a bubble 113 or cavity within the test material 112 and near the optical fiber tip 114. Continued transmission of the first laser beam 104 into the test material 112 causes the resulting bubble 113 to expand and then collapse. In certain embodiments, each subsequent emission of the first laser beam 104 from the first laser source 102 can generate a corresponding bubble. Generally, different power levels of the first laser beam 104 will result in bubbles 113 having different bubble characteristics or bubble formation profiles.

[0039] Simultaneously with first laser beam 104, second laser beam 108 is generated and propagates distally through optical fiber 110 and out of fiber tip 114. Thus, second laser beam 108 is delivered to the interface between test material 112 and fiber tip 114 of optical fiber 110. As bubble 113 forms and expands due to the thermal energy of first laser beam 104, the refractive index of second laser beam 108 at the interface changes as the interface transitions from, for example, a solid-liquid (e.g., sapphire-BSS) interface to a solid-vapor (e.g., sapphire-vaporized BSS) interface. For example, before bubble 113 forms, the refractive index between optical fiber 110 and test material 112 may be approximately 1.33. Once bubble 113 forms, the refractive index at the interface between optical fiber 110 and the vapor within bubble 113 may change to approximately 1.0.

[0040] The change in the refractive index at the distal end of optical fiber 110 causes the Fresnel coefficient at the distal end of optical fiber 110 to change, thereby causing the optical behavior of second laser beam 108 at the end of optical fiber 110 to change, thereby increasing the amount of second laser beam 108 being back-reflected through optical fiber 110. For example, in the presence of bubble 113, a larger portion of second laser beam 108 may be transiently reflected proximally by fiber tip 114 through optical fiber 110, while a smaller portion of second laser beam 108 may enter the test medium. A portion of the transmitted portion of the laser beam may further be reflected from the inner surface of bubble 113 back into the optical fiber.

[0041] The change in the optical behavior of the second laser beam 108 is detected by a sensor 124 of an optical detector 122, which continuously or discontinuously monitors / detects the reflected portion 120 of the second laser beam 108 and sends the optical detector output to a controller 126. The controller 126, coupled thereto, can then analyze the detected signal to determine metrics / characteristics of the reflected portion 120, which metrics / characteristics can be correlated with predefined or predetermined bubble characteristics or bubble formation profiles, and therefore determine the power of the first laser beam 104.

[0042] Figure 1B Shown Figure 1A

[0046] Another embodiment of the system 100. As mentioned above, additional optical components and / or repeaters are also contemplated for use with the system 100. Figure 1B The illustrated embodiment includes additional optical components in the form of wave plates (e.g., half-wave plate 130, quarter-wave plate 132), polarizing elements (polarizer 134, polarization cube 136), reflectors (e.g., reflectors 138, 140, 142), dichroic elements (e.g., dichroic mirror 144), lenses (e.g., focusing lenses 146, 148, collimating lenses, etc.), and the like. In some examples, the optical components can be used to facilitate power modification, laser isolation, transmission of identified wavelengths, and the like. One or more components may include coatings (e.g., anti-reflective coatings), materials, gratings, films, and the like for separating wavelengths, isolating laser light from back-reflected beams, and the like. In some embodiments, light can be transmitted using physical structures. In other embodiments, light can be transmitted through free space. In some embodiments, light can be transmitted via a combination of physical structures and free space.

[0043] It is noted that other surgical laser systems are also contemplated for use with the systems and methods for real-time laser power measurement of the present invention. Such surgical laser systems include those described in U.S. patent application serial number 17 / 662,148, filed on May 5, 2022, entitled “Surgical Laser System with Illumination” (U.S. Patent Publication No. 20220354692), which is incorporated herein by reference in its entirety.

[0044] Figure 2 A method 200 of performing laser power measurement using the system 100 is shown, according to certain embodiments described herein. Figures 3A to 3F One or more operations of method 200 are shown. Accordingly, for clarity, this document will be referred to as appropriate. Figure 2 and Figures 3A to 3F Describe them together.

[0045] Go to Figure 2At block 202 of the method 200 , a first laser beam 104 is generated by a first laser source 102 .

[0046] At block 204, a second laser beam 108 is generated by the first laser source 102 or the second laser source 106. In some embodiments, the second laser beam 108 is generated simultaneously with the first laser beam 104. In some embodiments, the second laser beam 108 is generated sequentially with the first laser beam 104. For example, the second laser beam 108 may be generated before the first laser beam 104 is generated, or vice versa.

[0047] At block 206 of method 200, the first laser beam 104 from the first laser source 102 is received into an optical fiber 110, which may be an optical fiber having one or more cores and / or claddings for simultaneously or sequentially propagating the first laser beam 104 and the second laser beam 108. In other embodiments, the optical fiber may be an unclad optical fiber, such as an unclad sapphire rod or a sapphire fiber.

[0048] At block 208, the optical fiber 110 directs (e.g., propagates) the first laser beam 104 to the test material 112 to form bubbles 113 in the test material 112. As described above, the test material 112 may include a liquid, such as water, saline, balanced salt solution (BSS), etc. The formation of the bubbles 113 changes the refractive index of the test material 112 in a short period of time, thereby changing the reflection coefficient of the interface between the fiber tip 114 of the optical fiber 110 and the test material 112.

[0049] Figures 3A to 3F The formation of bubbles 113 is shown during block 208. In particular, Figure 3A In FIG. 1 , a first laser beam 104 is transmitted from a fiber tip 114 into a test material 112. As the energy from the first laser beam 104 interacts with the test material 112, a first-stage bubble 113A begins to form. The formation of the first-stage bubble 113A is marked by the separation of the test material 112 from the fiber tip 114.

[0050] exist Figure 3B In the process, the second-stage bubble 113B continues to expand, and its volume increases relative to the first-stage bubble 113A. The expansion of the second-stage bubble 113B is due to the expansion of the vapor in the bubble 113 caused by the energy of the first laser beam 104.

[0051] exist Figure 3C In the third stage, the bubble 113C reaches a peak volume as the vapor pressure and dynamic movement of the bubble 113 reach equilibrium with the pressure of the test material 112.

[0052] exist Figure 3DIn the fourth stage, the bubble 113D begins to collapse, thereby reducing its volume and allowing the test material 112 to gradually approach the fiber tip 114 as energy from the bubble 113 dissipates.

[0053] exist Figure 3E In the embodiment, during the collapse, the volume of the fifth stage bubble 113E continues to decrease, and the fifth stage bubble 113E begins to separate from the optical fiber end 114.

[0054] exist Figure 3F In the sixth stage, the bubble 113F is completely separated from the optical fiber end 114 , and the test material 112 completely fills the gap between the bubble 113F and the optical fiber end 114 .

[0055] Now return to Figure 2 At block 210 of the method 200 , the second laser beam 108 is propagated into the optical fiber 110 by the second laser source 106 .

[0056] At block 212, the second laser beam 108 is directed through the optical fiber 110 toward the test material 112, as previously described. Figure 1A In some embodiments, the second laser beam 108 and the first laser beam 104 can be carried in the same core of the optical fiber 110, or in different cores in examples where the optical fiber 110 includes a multi-core arrangement. In some embodiments, the optical fiber 110 can be clad, and the first laser beam 104 and / or the second laser beam 108 propagate in the cladding.

[0057] At block 214 of method 200, a portion of second laser beam 108 (e.g., reflected portion 120) is back-reflected from the interface between fiber tip 114 and test material 112 and received by optical fiber 110. As bubble 113 forms, bubble 113 changes the reflection coefficient of the interface between fiber tip 114 and test material 112, thereby transiently modulating back-reflected portion 120. In some embodiments, a portion of second laser beam 108 may be reflected from bubble 113 and returned to optical fiber 110.

[0058] At block 216 , the reflected portion 120 of the second laser beam 108 is propagated back through the optical fiber 110 and directed to the optical detector 122 (such as by using one or more optical devices or repeaters).

[0059] At block 218, the method 200 includes receiving the reflected portion 120 of the second laser beam 108 at the sensor 124, and generating an optical detector output (e.g., a signal) by the sensor 124 and / or the optical detector 122 based on the received reflected portion 120. In some embodiments, the optical detector output is a signal profile (e.g., a measured reflection time signal, as described below). Figure 4Aand Figure 4B described in ).

[0060] In some embodiments, the optical detector output can be electrically amplified. In other embodiments, the electrical detector output can be passed through a high pass filter to separate the transient back reflection signal from the DC baseline, or a high pass filter can be used before or after the amplifier or between amplifier stages.

[0061] At block 220, method 200 includes determining the power level of first laser beam 104 in real time based on the optical detector output. For example, in some embodiments, various features and / or characteristics of the signal profile of reflected portion 120 may be correlated with features and / or characteristics of a predetermined or defined signal profile corresponding to one or more power levels of first laser beam 104. Such features and / or characteristics may include the number of peaks, the duration of the peaks, the rise time, the fall time, etc. In some embodiments, the signal profile of reflected portion 120 corresponds to the lifetime of a single bubble 113 formed by emitting first laser beam 104 into test material 112. Accordingly, in some embodiments, the power level of first laser beam 104 may be determined based on the duration component of reflected portion 120 determined from the optical detector output.

[0062] Now turn Figure 4A and Figure 4B , according to certain embodiments described herein, illustrates an exemplary signal profile of a reflected portion 120 of a second laser beam 108 detected by an optical detector 122 during the formation and collapse of a bubble 113 in a test material 112. While a particular shape of the signal profile is shown, other shapes may be produced, and power measurement capability is also provided.

[0063] exist Figure 4A In the example shown, a single signal profile 400 is shown that corresponds to the formation and collapse of a single bubble 113 caused by the first laser beam 104 at a certain power level. The signal profile 400 includes a graph of the signal voltage value of the reflected portion 120 of the second laser beam 108 as a function of time. In the example shown, the signal profile 400 of the reflected portion 120 includes a signal voltage value corresponding to Figure 3A The first peak 402 may indicate a slightly higher reflectivity because the interface between the first stage bubble 113A and the test material 112 may still be close to the fiber tip 114 but is beginning to separate from the fiber tip, causing a subsequent drop in reflectivity after the first peak 402.

[0064] After first peak 402, signal profile 400 steadily rises, corresponding to the formation of second-stage bubble 113B as the vapor within bubble 113 expands, and a larger portion of second laser beam 108 is reflected by fiber tip 114 during the formation of second-stage bubble 113B. In the illustrated example, signal profile 400 includes a second peak 404 corresponding to the formation of third-stage bubble 113C. Third-stage bubble 113C may represent the maximum volume of bubble 113, when the vapor pressure within bubble 113 balances the resistance of test material 112. Because the vapor within bubble 113 may be at its lowest density during third-stage bubble 113C, signal profile 400 may be highest at this second peak 404, based on the refractive index at fiber tip 114. As bubble 113 progresses to fourth-stage bubble 113D, signal profile 400 may begin to decline, with a more rapid decline occurring as bubble 113 collapses more rapidly through fifth-stage bubble 113E. In the illustrated embodiment, the separation of the bubble 113 from the fiber tip 114 in the sixth bubble stage 113F may return to a steady-state value at the optical detector 122 , indicating the end of the life cycle of the bubble 113 .

[0065] exist Figure 4B In the example shown, a graph 406 of fourteen different signal profiles 400 is shown, wherein each of the fourteen signal profiles 400 includes a graph of a signal voltage value varying over time. Each different signal profile 400 can correspond to a different power level output by the first laser source 102 when generating the first laser beam 104. In the example shown, it can be seen that increasing the output power (mW) (milliwatts) of the first laser source 102 results in a longer time trace of the corresponding signal profile 400. As further shown, the signal profile 400 of the second laser beam 108 produced by increasing the output power also has a higher intensity peak (e.g., corresponding to a higher collection level of light back-reflected from the curved surface of the bubble).

[0066] Once desired properties / characteristics of the signal profile 400 are determined, such as the pulse width or duration of the signal profile 400, such properties / characteristics may be mapped to one or more predetermined correlation curves to determine the power level of the first laser beam 104. In some embodiments, the correlation curves may depend at least in part on the phase change enthalpy of the test material 112, the diameter of the optical fiber 110, the pulse wavelength and / or duration of the first laser source 102, and the like. Figure 5. In the illustrated example, the measured characteristics of the signal profile 400 are shown as test value points 504 that are along or substantially along the correlation curve 502 that have been previously set based on the standardized sample. Using a correlation curve similar to the correlation curve 502, a user can determine the pulse energy of the first laser beam 104 and the power of the first laser source 102 based on the measured characteristics of the backreflected signal profile 400 of the second laser beam 108.

[0067] In some embodiments, the correlation curve 502 can be tuned to correspond to a specific test material 112 or group of test materials. For example, if the test material 112 is BSS, the corresponding correlation curve can be selected to determine the power level of the first laser beam 104. Similarly, a specific correlation curve can be established for at least one of the first laser source 102, the optical fiber 110, the optical fiber tip 114, etc.

[0068] In some embodiments, the lifetime of the bubble 113 generated by the laser in the liquid test material 112 can be calculated by the equation T=C(E-Ethreshold) 1 / 3 , where T is the lifetime of the bubble (in microseconds (μsec)), E is the energy of the laser pulse that generates the bubble (in microjoules (μJ)), and C and Ethreshold are constants that depend on the properties of the liquid test material 112, the laser source 102, and the light delivery mechanism (e.g., the optical fiber 110 and associated optics). For example, for a test material 113 composed of water, the constant C can be equal to or substantially equal to 13.3.

[0069] In some embodiments, the correlation curve 502 can be measured in a non-sterile environment before performing a surgical procedure for a particular surgical laser system 101 or surgical console, which can include one or more laser sources (e.g., laser sources 102 and / or 108), a fiber optic delivery system (e.g., optical fiber 110 and other optical components of the surgical laser system or console), and a test material 112. For example, a power meter can be used to measure the power output of the first laser source 102 at the fiber tip 114, and the transient backreflected pulse width versus the first laser pulse energy can be recorded for later use as a correlation curve.

[0070] The correlation curve 502 can also be established in a sterile environment by measuring the transient signal pulse width of the reflected portion 120 at several pulse energy levels (e.g., 40%, 50%, 60%, 70%, 80%, 90%, 100% of the maximum pulse energy) of the first laser source 102 generating the bubble, and fitting the pulse width and energy data points to T = C (E-Ethreshold) as described above. 1 / 3function, and obtain the C value and Ethreshold value.

[0071] Figure 6 A schematic diagram of a controller 602 according to embodiments disclosed herein is shown. The controller 602 generally represents the controller 126 described above and can be integrated with or operably coupled to a surgical console. In some embodiments, the controller 602 includes, but is not limited to, a user interface 606, an interconnect 608, and at least one I / O (input / output) device interface 610 that can allow various I / O devices (e.g., a keyboard, display, mouse device, pen input, etc.) to be connected to the controller 602. The controller 602 can communicate with one or more laser sources 612 (e.g., a laser source) via the interconnect 608. Figure 1A 102 and / or the second laser source 106) and one or more optical detectors 614 (e.g., Figure 1A In some embodiments, the one or more laser sources 612 and / or the one or more optical detectors 614 can be integrated with or operably coupled to the surgical console in addition to or separate from the controller 126.

[0072] Controller 602 further includes a CPU 604 (central processing unit), memory 616, and storage 618. CPU 604 is configured to retrieve and execute programmed instructions stored in memory 616. Similarly, CPU 604 can retrieve and store application data residing in memory 616. Interconnect 608 transmits programmed instructions and application data between CPU 604, I / O device interface 610, user interface 606, memory 616, storage 618, laser source 612, optical detector 614, and the like. CPU 604 may include a single CPU, multiple CPUs, a single CPU with multiple processing cores, and the like. Memory 616 may be random access memory, and storage 618 may be a disk drive. Furthermore, memory 616 and / or storage 618 may be any type of readily available memory, such as random access memory (RAM), read-only memory (ROM), floppy disk, hard disk, solid-state, flash memory, magnetic storage, or any other form of local or remote digital storage. In some embodiments, the memory 616 and / or storage device 618 include instructions that, when executed by the CPU 604, can affect the determination / measurement of the power level of the laser source 612 based on data received from the optical detector 614. In some embodiments, the CPU 604, memory 616, and storage device 618 can be the main processor and memory of the controller 602.

[0073] exist Figure 6In some embodiments, the CPU 604 of the controller 602 may include an integrated circuit capable of performing logic functions. In this manner, the CPU 604 is in the form of a standard integrated circuit package having power pins, input pins, and output pins. In other embodiments, the CPU 604 is a microprocessor. In other cases, the CPU 604 is not a programmable microprocessor but rather a dedicated controller.

[0074] exist Figure 6 In an embodiment, the controller 602 receives signals from the one or more optical detectors 614. For example, the signals may include optical detector outputs corresponding to reflected light received at sensors of the one or more optical detectors 614.

[0075] As shown, the storage device 618 includes material profiles 620 representing various test material types. For example, the material profiles 620 may include information corresponding to different test materials (e.g., saline, water, BSS, etc.), which may be used to generate correlation curves or determine the power level of the laser source 612 based on the generated correlation curves. In some embodiments, the material profiles 620 may include bubble formation characteristics of the corresponding test material. In some embodiments, each material profile 620 stored in the storage device 618 may include one correlation curve from a plurality of generated correlation curves 622 corresponding to the material of the material profile 620. The correlation curves 622 may be retrieved by the power level module 624 of the memory 616 to determine the power of the laser source 612 based on the optical detector output received from the one or more optical detectors 614.

[0076] As shown, the memory 616 includes a correlation curve generator 624 and a power level module 626. When executed, the correlation curve generator 624 generates a correlation curve for a given test material using signals received from the one or more optical detectors 614, which can be stored in the corresponding material profile 620. Conversely, the power level module 626, when executed, uses the signals received from the one or more optical detectors 614 in combination with one or more correlation curves 622 stored in the memory device 618 to determine the power of the laser source 612. In some embodiments, after the power level module 626 determines the power of the laser source 612, the controller 602 can output the determined power to a user graphical display or other I / O device in communication with the controller 602 via the I / O device interface 610.

[0077] In summary, embodiments of the present disclosure include systems and methods for laser power measurement, and more specifically, systems and methods for performing laser power measurement in a sterile operating environment. In certain embodiments described herein, power measurements are performed using two laser sources: 1) a first laser source configured to generate a first laser beam (therapeutic laser); and 2) a second laser source configured to generate a second laser beam (test laser). The first laser beam creates bubbles in a test material (e.g., water, saline, balanced salt solution, gel, etc.), and the second laser beam is reflected back, where the reflected portion of the second laser beam is measured to determine the lifetime of the bubbles and the lifetime measurement is correlated to a power value based on a correlation curve. Laser power measurements performed using back reflection of the second laser beam allow testing to be performed in a sterile environment, and embodiments may allow testing to be performed during surgical procedures. Testing of laser power levels can identify equipment problems, including incorrect assembly, component failure, misalignment due to movement or use before or during surgical procedures, and the like. Thus, the methods and systems described herein not only improve the safety of testing in a sterile environment, but also improve the ability to test the power level of a laser before and during operation without introducing contaminants.

[0078] The above-disclosed subject matter is to be considered illustrative and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments that fall within the true spirit and scope of the disclosure. Thus, to the maximum extent allowed by law, the scope of the present disclosure is to be determined by the broadest permissible interpretation of the appended claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.

Claims

1. A system for measuring laser power and pulse energy, the system comprising: a first laser source configured to generate a first laser beam in a pulsed form; a second laser source configured to generate a second laser beam; An optical fiber, the optical fiber being configured to: receiving the first laser beam from the first laser source; directing the first laser beam toward a test material to form bubbles in the test material; receiving the second laser beam from the second laser source; directing the second laser beam toward the test material; receiving a reflected portion of the second laser beam from an interface between the test material and the optical fiber; as well as directing a reflected portion of the second laser beam to an optical detector; The optical detector is configured to: receiving a reflected portion of the second laser beam from the optical fiber; as well as generating an optical detector output based on the reflected portion of the second laser beam, wherein a waveform shape of the optical detector output depends on a pulse energy of the first laser beam; as well as A controller is configured to determine a power and a pulse energy of the first laser beam based on the optical detector output.

2. The system of claim 1, wherein: The optical detector includes a photodiode optical sensor configured to generate the optical detector output.

3. The system of claim 1, wherein: The optical detector is further configured to measure the lifetime of the bubble by determining a change in reflectivity of the second laser beam caused by a change in a refractive index at an interface of the optical fiber.

4. The system of claim 1, wherein: At least a portion of the optical fiber comprises sapphire.

5. The system of claim 1, further comprising a dichroic element positioned to direct the second laser beam from the second laser source to the optical fiber.

6. The system of claim 1, wherein: The first laser beam includes infrared laser light.

7. The system of claim 1, wherein: The optical detector output is filtered by a high pass filter before the controller determines the power and pulse energy of the first laser beam.

8. A method comprising: generating a first laser beam in a pulsed form by a first laser source; generating a second laser beam by a second laser source; receiving the first laser beam from the first laser source through an optical fiber; directing the first laser beam to a test material through the optical fiber to form bubbles in the test material; receiving the second laser beam from the second laser source at the optical fiber; guiding the second laser beam to the test material by the optical fiber; receiving, at the optical fiber, a reflected portion of the second laser beam from an interface between the test material and the optical fiber; directing the reflected portion of the second laser beam to an optical detector via the optical fiber; receiving, at the optical detector, a reflected portion of the second laser beam from the optical fiber; as well as The power and pulse energy of the first laser beam are determined by a controller in communication with the optical detector based on changes in the reflected portion of the second laser beam received at the optical detector.

9. The method of claim 8, wherein: The optical detector includes a photodiode optical sensor.

10. The method of claim 8, wherein: The optical detector and the controller are further configured to measure the lifetime of the bubble by determining a change in reflectivity of the second laser beam due to a change in refractive index at an interface of the optical fiber and the test material.

11. The method of claim 8, wherein: At least a portion of the optical fiber comprises sapphire.

12. The method of claim 8, wherein: The first laser beam includes infrared laser light.

13. The method of claim 8, wherein: Prior to determining the power and pulse energy of the first laser beam, the optical detector output is filtered by a high pass filter.

14. The method of claim 8, wherein: The determining of the power and pulse energy of the first laser beam is further based on a correlation curve that relates the pulse energy level of the first laser beam to the pulse width of the reflected portion of the second laser beam.

15. The method of claim 14, wherein: The correlation curve is determined by measuring the pulse width of the reflected portion of the second laser light at several fractional pulse energy levels of the first laser beam and fitting the measurement results to the equation T = C (E - Ethreshold) 1 / 3 .

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