Dynamic correction for acousto-optic deflectors

Abstract

An optical scanner can include a sampler to receive a light beam and provide a sampled light beam including a portion of the light beam, a dispersive element to spectrally disperse the sampled light beam along a dispersion direction, one or more detectors to receive at least a portion of the sampled light beam dispersed along the dispersion direction, one or more acousto-optic deflectors (AODs) configured to deflect the light beam from the sampler, and a controller. The controller can determine a centroid of the sampled light beam dispersed along the dispersion direction based on a signal from at least one of the one or more detectors and generate a drive signal for at least one of the one or more AODs to deflect the light beam from the sampler along a selected deflection angle based on the centroid.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to an optical beam scanner, and more particularly to dynamic correction of an optical beam scanner in the presence of spectral variation of a scanned beam. BACKGROUND

[0002] Acousto-optic deflectors (AODs) can be used as beam scanning devices in a wide range of applications. AODs beneficially provide relatively fast scanning speeds but are sensitive to spectral variation of a scanned beam. Accordingly, it can be desirable to develop systems and methods for addressing the aforementioned deficiencies. SUMMARY

[0003] According to one or more illustrative embodiments of the present disclosure, an optical scanner is disclosed. In one illustrative embodiment, the optical scanner includes a sampler for receiving a beam and providing a sampled beam including a portion of the beam. In another illustrative embodiment, the optical scanner includes a dispersive element for spectrally dispersing the sampled beam along a dispersion direction. In another illustrative embodiment, the optical scanner includes one or more detectors for receiving at least a portion of the sampled beam dispersed along the dispersion direction. In another illustrative embodiment, the optical scanner includes one or more acousto-optic deflectors (AODs) for deflecting the beam from the sampler. In another illustrative embodiment, the optical scanner includes a controller. In another illustrative embodiment, the controller determines a centroid of the sampled beam dispersed along the dispersion direction based on a signal from at least one of the one or more detectors. In another illustrative embodiment, the controller generates a drive signal for at least one of the one or more AODs to deflect the beam from the sampler along a selected deflection angle based on the centroid.

[0004] According to one or more illustrative embodiments of the disclosure, a system is disclosed. In one illustrative embodiment, the system includes a light source configured to generate a light beam. In another illustrative embodiment, the system includes a scanner. In another illustrative embodiment, the scanner includes a sampler to receive the light beam and provide a sampled light beam including a portion of the light beam, a dispersive element to spectrally disperse the sampled light beam along a dispersion direction, one or more detectors to receive at least a portion of the sampled light beam dispersed along the dispersion direction, and one or more acousto-optic deflectors (AODs) to deflect the light beam from the sampler. In another illustrative embodiment, the system includes a controller. In another illustrative embodiment, the controller determines a centroid of the sampled light beam dispersed along the dispersion direction based on a signal from at least one of the one or more detectors. In another illustrative embodiment, the controller generates a drive signal for at least one of the one or more AODs to deflect the light beam from the sampler along a selected deflection angle based on the centroid. In another illustrative embodiment, the system includes one or more focusing optics configured to focus the light beam deflected by the one or more AODs to a sample.

[0005] According to one or more illustrative embodiments of the disclosure, a method is disclosed. In one illustrative embodiment, the method includes generating a sampled light beam from a received light beam, where the sampled light beam includes a portion of the light beam. In another illustrative embodiment, the method includes spectrally dispersing the sampled light beam along a dispersion direction. In another illustrative embodiment, the method includes detecting, with one or more detectors, at least a portion of the sampled light beam dispersed along the dispersion direction. In another illustrative embodiment, the method includes determining a centroid of the sampled light beam dispersed along the dispersion direction based on a signal from at least one of the one or more detectors. In another illustrative embodiment, the method includes generating a drive signal for an acousto-optic deflector (AOD) to deflect the light beam along a selected deflection angle based on the centroid. In another illustrative embodiment, the method includes deflecting the light beam with the AOD driven by the drive signal.

[0006] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not necessarily restrictive of the application as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the general description, serve to explain the principles of the application. BRIEF DESCRIPTION OF DRAWINGS

[0007] Those skilled in the art will better appreciate the many advantages of the present disclosure upon consideration of the detailed description in conjunction with the accompanying drawings.

[0008] Figure 1A is a block diagram of an optical scanner according to one or more embodiments of the present disclosure.

[0009] Figure 1B is a block diagram of a system including an optical scanner according to one or more embodiments of the present disclosure.

[0010] Figure 2 is a simplified schematic of an acousto-optic deflector (AOD) according to one or more embodiments of the present disclosure.

[0011] Figure 3 is a plot of a spatially dispersed sampled light beam according to one or more embodiments of the present disclosure.

[0012] Figure 4A is a simplified conceptual schematic of a first spectrally dispersed sampled light beam including a single lobe associated with a first wavelength according to one or more embodiments of the present disclosure.

[0013] Figure 4B is a simplified conceptual schematic of a second spectrally dispersed sampled light beam including a single lobe associated with a second wavelength according to one or more embodiments of the present disclosure.

[0014] Figure 4C is a simplified conceptual schematic of a third spectrally dispersed sampled light beam including a first lobe associated with a third wavelength and a second lobe associated with a fourth wavelength according to one or more embodiments of the present disclosure.

[0015] Figure 5 is a simplified schematic of a portion of an optical scanner including an additional detector for monitoring performance of an AOD according to one or more embodiments of the present disclosure.

[0016] Figure 6 is a flowchart illustrating steps performed in a method for dynamic control of an optical scanner according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0017] Reference will now be made in detail to the disclosed subject matter, examples of which are illustrated in the accompanying drawings. The present disclosure is described with respect to particular embodiments and specific features thereof. The embodiments set forth herein are considered illustrative and not restrictive of the disclosure. Those of ordinary skill in the art will readily recognize variations and modifications of the embodiments discussed without departing from the spirit and scope of the disclosure.

[0018] Embodiments of the present disclosure relate to systems and methods for dynamically controlling an optical scanner to compensate for spectral variations of a light beam (e.g., a laser beam or the like).

[0019] In some embodiments, the optical scanner includes at least one acousto-optic deflector (AOD) for receiving and redirecting a light beam (e.g., a scanning light beam), one or more detectors for monitoring spectral variations of the light beam, and a controller for providing a driving signal to the AOD, the driving signal dynamically adjusted to compensate for spectral variations of the light beam that can be measured by at least one of the one or more detectors.

[0020] The AOD can include one or more transducers for generating acoustic waves in a host material, where driving the transducers with a periodic driving signal can form a diffraction grating in the host material. In this way, an incident light beam can be redirected via diffraction, where the deflection angle of the light beam from the AOD (e.g., the diffraction angle from the diffraction grating) can be controlled based on the frequency of the driving signal, and the intensity of the light beam from the AOD can be controlled based on the amplitude of the driving signal.

[0021] It is contemplated herein that such an AOD can beneficially provide a higher scanning speed than mechanical scanners (e.g., galvo mirrors, rotating polygons, or the like), but can be highly sensitive to spectral variations of the scanned light beam. In particular, spectral variations of the light beam can result in variations of the diffraction angle of the light beam by the AOD and thus variations of the deflection angle of the light beam. However, the systems and methods disclosed herein can allow for dynamic compensation of spectral variations to provide fast and accurate optical scanning with an AOD despite spectral variations.

[0022] Additional embodiments of the present disclosure relate to systems and methods for dynamically compensating for power fluctuations of a light beam when using wavelength-sensitive polarizing optics. Some polarizing optics can provide non-uniform performance (e.g., transmittance and / or reflectance) for different wavelengths. In this case, when such wavelength-sensitive polarizing optics are used in an optical scanner, spectral variations of the light beam can result in power fluctuations. In some embodiments, the controller can further dynamically adjust the amplitude of the driving signal to the AOD to adjust the power of the light beam exiting the AOD and thus compensate for power fluctuations associated with the interaction with the wavelength-sensitive polarizing optics. Such wavelength-sensitive polarizing optics can be placed before or after the AOD.

[0023] Additional embodiments of the present disclosure relate to systems and methods for dynamically compensating for variations in beam size of an optical beam. For example, when the power distribution of an optical beam dynamically changes between different spectral bands, the beam size and positioning accuracy of the optical beam can be directly affected. Moreover, the case can be that the spectral variation of the optical beam is associated with operation of an associated light source (e.g., a laser source) in different optical modes, where each optical mode can also provide different beam characteristics (e.g., beam size, beam divergence, or the like). In this manner, switching between these different modes (e.g., mode hopping) and / or simultaneous laser emission of different modes can result in any combination of spectral variation and / or variation in beam characteristics. In some embodiments, an optical scanner includes one or more detectors for monitoring the beam size of an optical beam and one or more adaptive optics (e.g., deformable mirrors, microelectromechanical system (MEMS) devices, phase modulators, or the like), where a controller dynamically generates drive signals for the adaptive optics to compensate for variations in beam size.

[0024] Reference will now be made to the Figures 1A to 6 , systems and methods for optical scanning in the presence of spectral variation and / or beam size variation are described in greater detail in accordance with one or more embodiments of the present disclosure.

[0025] Figure 1A is a block diagram of an optical scanner 100 in accordance with one or more embodiments of the present disclosure. Figure 1B is a block diagram of a system 102 including the optical scanner 100 in accordance with one or more embodiments of the present disclosure.

[0026] In some embodiments, the optical scanner 100 includes a light source 104 for generating a light beam 106 and at least one angle-of-deflection (AOD) 108 for controlling the deflection angle of the light beam 106. The optical scanner 100 may further include a controller 110 having one or more processors 112 configured to execute a set of program instructions held in a memory 114 (e.g., a memory device), wherein the controller 110 may generate at least one drive signal 116 for the AOD 108. In this way, the controller 110 may guide or otherwise control the AOD 108 based on the drive signal 116 to guide the light beam 106 along a specific deflection angle, scanning pattern, or the like. As described in more detail below, the controller 110 may further adjust one or more aspects of the drive signal 116 to compensate for spectral variations in the light beam 106 and provide a consistent deflection angle of the light beam 106 via the AOD 108. For example, the optical scanner 100 can monitor the spectral variation of the beam 106 by: sampling a portion of the beam 106 using a sampler 118 to form a sampled beam 120; dispersing the spectrum of the sampled beam 120 using a dispersive element 122; and collecting at least a portion of the spectrally dispersed sampled beam 120 using one or more detectors 124 coupled to the controller 110.

[0027] In addition, although Figure 1A While not explicitly shown, the optical scanner 100 may generally include any number of AODs 108. For example, the optical scanner 100 may include multiple AODs 108 arranged to provide scanning of the beam 106 along multiple directions (e.g., orthogonal directions). In the case of multiple AODs 108, the controller 110 may adjust one or more aspects of the drive signal 116 associated with each AOD 108 to compensate for spectral variations of the beam 106 and to provide a consistent deflection angle of the beam 106 through each AOD 108. In this way, any description herein of the operation or correction of the AODs 108 can be extended to apply to multiple AODs 108.

[0028] The one or more processors 112 of the controller 110 can include any processor or processing element known in the art. In this sense, the one or more processors 112 can include any microprocessor-type device configured to execute algorithms and / or instructions. For the purposes of the present disclosure, the term "processor" or "processing element" can be broadly defined to encompass any device having one or more processing or logic elements (e.g., one or more microprocessor devices, one or more application specific integrated circuit (ASIC) devices, one or more field programmable gate arrays (FPGAs), or one or more digital signal processors (DSPs)). In this sense, the one or more processors 112 can include any device configured to execute algorithms and / or instructions (e.g., program instructions stored in memory). In some embodiments, the one or more processors 112 can be embodied as a desktop computer, mainframe computer system, workstation, image computer, parallel processor, networked computer, or any other computer system configured to execute a program configured to operate the optical scanner 100 or in conjunction with the optical scanner 100, as described throughout the present disclosure. Moreover, different subsystems of the optical scanner 100 can include processors or logic elements suitable for carrying out at least portions of the steps described in the present disclosure. Accordingly, the above description should not be interpreted as a limitation on embodiments of the present disclosure but merely an illustration. Further, the steps described throughout the present disclosure can be carried out by a single controller or, alternatively, multiple controllers. Additionally, the controller 110 can include one or more controllers housed in a common housing or within multiple housings. In this manner, any controller or combination of controllers can be individually packaged as a module suitable for integration into the optical scanner 100.

[0029] The memory 114 can include any storage medium known in the art suitable for storing program instructions executable by the associated one or more processors 112. For example, the memory 114 can include a non-transitory memory medium. By way of further example, the memory 114 can include, but is not limited to, read-only memory (ROM), random access memory (RAM), magnetic or optical memory devices (e.g., magnetic disks), magnetic tape, solid state drives, and the like. It is further noted that the memory 114 can be housed in a common controller housing with the one or more processors 112. In some embodiments, the memory 114 can be remotely located relative to the physical location of the one or more processors 112 and the controller 110. For example, the one or more processors 112 of the controller 110 can access a remote memory (e.g., a server) that can be accessed over a network (e.g., the Internet, an intranet, and the like).

[0030] As another example, the controller 110 can include or be coupled with one or more encoders (e.g., optical encoders) that can be used for any suitable purpose, including but not limited to monitoring the position of the beam along one or more scan axes and providing associated feedback for control.

[0031] The optical scanner 100 can be integrated into any suitable system for dynamic beam control. As illustration, Figure 1B The optical scanner 100 is depicted in use in a system 102 suitable for material processing. In some embodiments, the system 102 includes a stage 126 for securing a sample 128. In some embodiments, the system 102 includes one or more focusing optics 130 for focusing the beam 106 from the optical scanner 100 onto the sample 128. Thus, the system 102 can direct or scan the beam 106 across the sample 128 in any mode, with the AOD 108 within the optical scanner 100 adjusted to compensate for spectral variations of the beam 106 so that the position of the beam 106 on the sample 128 can be consistent despite the spectral variations.

[0032] The focusing optics 130 can include any number or type of focusing optics suitable for focusing the beam 106 onto the sample 128. In some embodiments, the focusing optics 130 include an F-theta lens to provide consistent focusing of the beam 106 across a flat plane and linear displacement across the sample 128 that varies as a function of input angle (e.g., associated with the angle of deflection of the beam 106 from the optical scanner 100).

[0033] In some embodiments, the system 102 includes one or more additional components for providing additional control over the position of the beam 106 on the sample 128. For example, the stage 126 can include a translation stage with one or more linear or angular actuators to adjust the position of the sample 128 along any number of degrees of freedom. As another example, the system 102 can include an additional deflector 132, such as but not limited to a galvanometer, a rotating polygon, or an additional AOD as depicted in Figure 1B this way, the scanning range can be increased beyond that of the optical scanner 100. For example, a mechanical beam scanner (e.g., the stage 126 or galvanometer as depicted in Figure 1B may provide a larger scanning range than the optical scanner 100 but with a relatively slow scanning rate.

[0034] The system 102 can further include any number of additional optics for controlling various aspects of the beam 106, such as but not limited to optical relays, beam expanders, polarizers, spectral filters, spatial filters, or apodizers. Although not explicitly illustrated, such additional optics can be distributed at any suitable location throughout the system 102 and / or within the optical scanner 100.

[0035] In some embodiments, the system 102 and / or the optical scanner 100 further includes an adaptive optical element 134 that provides spatially resolved control over portions of the light beam 106. In this way, properties such as, but not limited to, beam size, beam divergence, or focal properties of the light beam 106 deflected by the AOD 108 can be adjusted to provide consistent performance despite variations in the light beam 106. For example, the adaptive optical element 134 can be used within the system 102 to provide consistent focused spot size on the sample 128 despite variations in the light beam 106.

[0036] Reference is now generally made to Figure 1A In accordance with one or more embodiments of the disclosure, various aspects of the optical scanner 100 are described in greater detail.

[0037] The light beam 106 can include light of one or more selected wavelengths, including but not limited to ultraviolet (UV) radiation, visible radiation, or infrared (IR) radiation. Furthermore, the light beam 106 from the light source 104 can have any temporal profile, including but not limited to a continuous wave (CW) profile, a pulsed profile, or a modulated profile.

[0038] The light source 104 can generally include any type of illumination source suitable for providing at least one light beam 106, including but not limited to a laser source or a light emitting diode (LED). It should be noted that the light source 104 can be integrated within the optical scanner 100, the system 102, or as an external component. In some embodiments, the light source 104 includes a narrowband laser source that provides light centered around a central wavelength. It is contemplated herein that the smaller the bandwidth of the light beam 106, the less spatial dispersion will be induced by a dispersive element, such as but not limited to the AOD 108.

[0039] In some embodiments, the light source 104 is a carbon dioxide (CO2) laser source. For example, a CO2laser can provide a light beam 106 having a wavelength in the range of 9 to 12 nanometers, although this is intended to be illustrative and not limiting.

[0040] The AOD 108 can include any type of deflector known in the art suitable for controlling the deflection angle of the light beam 106 via diffraction by acoustic waves in a material. Figure 2 is a simplified schematic of an AOD 108 in accordance with one or more embodiments of the disclosure.

[0041] In some embodiments, the AOD 108 includes at least one transducer 202 coupled to a host material 204. The host material 204 can include any type of material suitable for interacting with the light beam 106, such as but not limited to a glass or a crystal. For example, the host material 204 can be transparent to the light beam 106. To illustrate, the host material 204 can have an absorption below a selected threshold for a wavelength associated with the light beam 106, and / or can have a transmissivity above a selected threshold for a wavelength associated with the light beam 106.

[0042] The transducer 202 can be any component suitable for generating acoustic waves in the host material 204. In some embodiments, the transducer 202 is a piezoelectric material that can expand or contract in response to an applied voltage (e.g., the drive signal 116), which can generate acoustic waves in the host material 204.

[0043] In some embodiments, the AOD 108 (e.g., one or more transducers in the AOD 108) is driven by the periodic drive signal 116 to generate a periodic distribution of acoustic waves in the host material 204, which can operate as a diffraction grating 206 suitable for diffracting the light beam 106. In particular, the periodic distribution of acoustic waves can provide a periodic distribution of refractive index in the host material 204 operating as the diffraction grating 206.

[0044] Diffracting the light beam 106 by the diffraction grating 206 can generally result in any number of diffraction orders (e.g., zeroth order diffraction 208, first order diffraction 210, second order diffraction 212, or the like). In this configuration, any of the diffraction orders can be used as the deflected light beam 106. In some embodiments, the AOD 108 is configured such that the light beam 106 interacts with the diffraction grating 206 at or near a Bragg angle, such that a majority of the energy in the light beam 106 is diffracted as the first order diffraction 210 (e.g., +1st order diffraction or -1st order diffraction). Thus, the first order diffraction 210 can represent the deflected light beam 106, and a deflection angle 214 of the light beam 106 from the AOD 108 can correspond to a first order diffraction angle 216.

[0045] Diffracting the light beam 106 by the diffraction grating 206 in the AOD 108 can generally be governed by the following grating equation:

[0046] d(sin θ i -sin θ m ) = mλ (1)

[0047] where d is a period of the diffraction grating 206, m is a diffraction order, λ is a wavelength of the light beam 106, θ i is an angle of incidence of the light beam 106, and θ m is a diffraction angle of an associated diffraction order of the light beam 106. Thus, the first order diffraction angle 216 is

[0048] θ1= asin(sin θ i and varies based on a wavelength (λ) of the light beam 106 and a period (d) of the diffraction grating 206. More generally, equation (1) illustrates that non-zero diffraction orders, including but not limited to the first order diffraction 210, are spectrally dispersed such that the diffraction angle θ m and varies based on a wavelength (λ) of the light beam 106.

[0049] The power of the first order diffraction 210 and thus the efficiency of the AOD 108 for deflecting the light beam 106 can depend on various factors, including but not limited to a magnitude of a variation of a refractive index (Δη, where n is the refractive index of the host material 204) associated with the host material 204 of the diffraction grating 206, which can be referred to as a modulation depth of the diffraction grating 206. In the AOD 108, this modulation depth (Δη) can be based on an amplitude of the acoustic wave produced by the transducer 202.

[0050] For a given wavelength (λ) of the light beam 106, the first order diffraction angle 216 and thus the deflection angle 214 of the light beam 106 from the AOD 108 can be changed within a scan range (e.g., a walk window) by adjusting a frequency of the drive signal 116. The period (d) of the diffraction grating 206 can be inversely related to the frequency of the drive signal 116. For example, the controller 110 can produce the drive signal 116 and can adjust the frequency of the drive signal 116 in any selected pattern to adjust the deflection angle 214 in any selected pattern.

[0051] It is contemplated herein that the light source 104 can exhibit various instabilities, such as but not limited to instabilities in a spectrum or a beam size of the light beam 106. In the case of a laser source, such instabilities can but need not be associated with mode hopping between different support modes, each of which can have a different wavelength (e.g., a center wavelength).

[0052] Spectral variations of the light beam 106 (e.g., associated with such instabilities of the light source 104 or more generally associated with any mechanism) can induce errors in the deflection angle of the light beam 106. It is considered a non-limiting example in Figure 2 Based on equations (1) and (2), spectral variations of the light beam 106 can affect the first order diffraction angle 216 and thus the deflection angle 214 of the light beam 106 from the AOD 108. Thus, a shift in the wavelength (λ) of the light beam 106 from an expected value (e.g., due to spectral variations) can result in an error in the deflection angle 214 from the AOD 108.

[0053] While such deflection angle errors can be avoided through the use of wavelength-insensitive scanning techniques (e.g., mechanical techniques such as, but not limited to, galvanometer or rotating polygon) or by selecting a light source 104 with reduced spectral variation, such approaches are not always desirable. For example, mechanical beam scanning techniques can generally have a slower positioning rate (e.g., scan rate) and thus can limit the processing capability of the system. As another example, techniques that provide a beam 106 with high spectral stability can limit the achievable power of the beam 106. In other words, mode hopping (and associated spectral instability) can be a result of high power operation for some laser sources such as, but not limited to, CO2laser sources.

[0054] Thus, in some applications, it can be desirable to utilize an optical scanner 100 including an AOD 108 in conjunction with a light source 104 that exhibits spectral variation. In this manner, the light source 104 can be selected to provide a beam 106 with a selected power without regard to spectral instability and without sacrificing scan speed or accuracy.

[0055] Referring again to Figures 1A to 1B In some embodiments, the optical scanner 100 includes various components for compensating for the spectral variation of the beam 106.

[0056] In some embodiments, the optical scanner 100 includes a sampler 118 for generating a sampled beam 120 from the beam 106, a dispersive element 122 for spectrally dispersing the sampled beam 120, and one or more detectors 124 for capturing at least a portion of the spectrally dispersed sampled beam 120. In this manner, the one or more detectors 124 can generate a signal indicative of the spectral variation of the sampled beam 120 and thus the spectral variation of the beam 106. The controller 110 can then adjust the drive signal 116 of the AOD 108 to compensate for the spectral variation of the beam 106 over time to provide accurate deflection angles 214 of the beam 106 despite the spectral variation.

[0057] The sampler 118 can include any optical component known in the art suitable for extracting a portion of the beam 106 as the sampled beam 120. For example, the sampler 118 can include, but is not limited to, an optical wedge or a beam splitter. As another example, the sampler 118 can include a mirror that provides less than 100% reflectance, where a portion of the beam 106 propagates through the mirror and is used as the sampled beam 120.

[0058] The dispersing element 122 can include any optical element known in the art suitable for spatially dispersing the sampled light beam 120, such as but not limited to a diffraction grating or a prism. In this manner, the dispersing element 122 (and the detector 124) can be an inline or real-time spectrometer. For example, in the case of a diffraction grating, the dispersing element 122 can produce a plurality of diffraction orders based on Equation (1), where the non-zero order diffractions are spectrally dispersed. In some embodiments, as described with respect to the diffraction grating 206 of the AOD 108, the dispersing element 122 is arranged to satisfy the Bragg condition such that a majority of the power of the sampled light beam 120 is diffracted as a first order diffraction.

[0059] The dispersing element 122 can generally have any dispersion value. In some embodiments, the dispersing element 122 has sufficient dispersion to enable detection of spectral variations of the sampled light beam 120 by at least one of the one or more detectors 124. By way of illustration, the dispersing element 122 can include, but is not required to include, a diffraction grating having 150 lines per mm of ruling to provide sufficient dispersion to enable detection of spectral variations of the sampled light beam 120 by at least one of the one or more detectors 124.

[0060] Figure 3 is a plot of a spatially dispersed sampled light beam 120 in accordance with one or more embodiments of the present disclosure. In particular, Figure 3 corresponds to a spatially dispersed sampled light beam 120 associated with a CO2laser, and depicts light dispersed along a dispersion direction 302.

[0061] Spectral variations of the light beam 106 can manifest in a variety of ways and can depend on the particular light source 104. In some embodiments, the light beam 106 can include power centered at a single wavelength (e.g., a single center wavelength), where this wavelength can shift over time. For example, this behavior can be associated with, but is not limited to, thermal variations in the light source 104. In some embodiments, as depicted in Figure 3 The light source 104 can produce a light beam 106 having power centered at one or more wavelengths associated with one or more optical modes. In this manner, any number of optical modes (and associated wavelengths) can exist at any particular time, and the distribution of wavelengths can change over time (e.g., due to mode hopping).

[0062] The one or more detectors 124 can include any type of detector known in the art suitable for detecting spectral variations of the sampled light beam 120 when coupled with the dispersing element 122. In some embodiments, the detector 124 is formed as a multi-pixel detector, where at least two pixels are distributed along the dispersion direction 302 provided by the dispersing element 122. In this manner, different pixels of the detector 124 along the dispersion direction 302 can capture different wavelengths or ranges of wavelengths of the sampled light beam 120.

[0063] A lateral shift of light along the dispersion direction 302 as measured by the detector 124 can be calibrated as a wavelength shift of the sampled light beam 120 based on a value of dispersion provided by the dispersive element 122 and a separation distance between the dispersive element 122 and the detector 124. For example, the value of dispersion provided by the dispersive element 122 can be characterized as Δθ / Δλ, where Δθ is an angular shift of the deflection angle 214 associated with a wavelength shift of Δλ. This can then be mapped to a linear shift Δ1 on the detector 124.

[0064] The controller 110 can then provide the drive signal 116 to the AOD 108 using any technique suitable to compensate for spectral variations of the light beam 106 (e.g., as measured on the sampled light beam 120). In some embodiments, the controller 110 determines a center of mass (COM) of the spectrally dispersed sampled light beam 120 and dynamically adjusts a frequency of the drive signal 116 to the AOD 108 based on the COM of the spectrally dispersed sampled light beam 120.

[0065] By way of illustration, the controller 110 can calculate a first frequency (f0) of the drive signal 116. This first frequency can be selected to provide a desired deflection angle 214 of the light beam 106 based on an expected wavelength (λ0) of the sampled light beam 120 and thus based on an expected COM (COM0) of the spectrally dispersed sampled light beam 120 as measured by the detector 124.

[0066] The expected COM (COM0) of the spectrally dispersed sampled light beam 120 can correspond to any value and can correspond to a central position on the detector 124. For example, if the spectrum of the light beam 106 (and thus the sampled light beam 120) varies over a known spectral range, then the associated COM of the spectrally dispersed sampled light beam 120 can vary over a range of known positions on the plane of the detector 124. The detector 124 can then be placed at any suitable position to capture this range of known positions. In some embodiments, the center of the detector 124 is placed in the center of this range of known positions.

[0067] The controller 110 can receive a signal from the detector 124 indicative of the COM of the spectrally dispersed sampled light beam 120. The controller 110 can then determine an adjustment frequency (Δf) needed to compensate for a shift (ΔCOM) of the COM of the spectrally dispersed sampled light beam 120 from an expected value.

[0068] The controller 110 can then provide the drive signal 116 to the AOD 108 with a second frequency (f2) corresponding to the first frequency (f1) plus or minus the adjustment frequency (Δf) based on any measured deviation (ΔCOM) of the COM of the spectrally dispersed sampled light beam 120 from an expected value.

[0069] It is contemplated herein that adjusting the frequency of the drive signal 116 based on the COM of the spectrally dispersed sampled beam 120 can provide a robust and effective technique suitable for compensating for a wide variety of spectral variations. However, the detector 124 placed after the dispersive element 122 does not necessarily need to resolve the spectral power in each optical mode or at each particular wavelength of the sampled beam 120. Rather, the COM of the spectrally dispersed sampled beam 120 can provide an indicator of spectral variations in a manner that is relevant to the compensation of the effects of the spectral variations on the deflection angle 214.

[0070] For example, in the case that the spectrum of the sampled beam 120 (and thus the beam 106) includes power centered at a single central wavelength that shifts over time, the COM of the sampled beam 120 can correspond to this central wavelength, such that the frequency (f2) of the drive signal 116 can be adjusted to track this central wavelength.

[0071] As another example, in the case that the spectrum of the sampled beam 120 is more complex and includes power at multiple wavelengths that shift over time, the COM of the sampled beam 120 can correspond to an effective central wavelength of the spectral power distribution. In some cases, the sampled beam 120 can not have any power at this effective central wavelength. However, adjusting the deflection angle 214 of the beam 106 based on this effective central wavelength can provide accurate optical scanning based on the effective central wavelength of the spectral power distribution.

[0072] To illustrate, Figures 4A to 4C COMs of the spectrally dispersed sampled beam 120 in response to various spectral variations are depicted in accordance with one or more embodiments of the disclosure. Figure 4A is a simplified conceptual schematic of a first spectrally dispersed sampled beam 120 including a single lobe 402 associated with a first wavelength (λ0) in accordance with one or more embodiments of the disclosure. Figure 4B is a simplified conceptual schematic of a second spectrally dispersed sampled beam 120 including a single lobe 404 associated with a second wavelength (λ1) in accordance with one or more embodiments of the disclosure. Figure 4C is a simplified conceptual schematic of a third spectrally dispersed sampled beam 120 including a first lobe 406 associated with a third wavelength (λ2) and a second lobe 408 associated with a fourth wavelength (λ3) in accordance with one or more embodiments of the disclosure.

[0073] In Figures 4A to 4C , the lobes 402-408 each have a symmetric power distribution (not illustrated) and the same physical size. In Figure 4A , the lobes 402-408 each have a symmetric power distribution (not illustrated) and the same physical size. In 4B , the lobes 402-408 each have a symmetric power distribution (not illustrated) and the same physical size. In Figure 4CIn this case, the power of the sampled beam 120 is evenly distributed between the lobes 406, 408.

[0074] In Figure 4A this case, the COM of the sampled beam 120 can correspond to the center of the lobe 402. Further, the center of the lobe 402 can correspond to a physical center of the detector 124, which can correspond to the expected COM position (COM0). In this case, Figure 4A may correspond to a case in which no compensation of the frequency of the drive signal 116 is needed.

[0075] In Figure 4B this case, the COM of the spectrally distributed sampled beam 120 can correspond to the center of the lobe 404. This case can correspond to a simple shift of the center wavelength of the sampled beam 120 with respect to λ0to λ1and a corresponding COM shift (ΔCOM) of the spectrally distributed sampled beam 120. Accordingly, the controller 110 can provide a frequency adjustment (Δf) to compensate for the COM shift (ΔCOM).

[0076] In Figure 4C this case, the COM of the spectrally distributed sampled beam 120 can correspond to an additional wavelength λ4, where the sampled beam 120 can or can not provide light at this wavelength. For example, Figure 4C two lobes at wavelengths λ2and λ3, where the COM corresponds to an additional wavelength λ4that is positioned between the two lobes. In any case, the COM of the spectral power distribution of the sampled beam 120 can correspond to the wavelength λ4, and thus can provide a convenient wavelength to use as a basis for adjusting the frequency of the drive signal 116 to deflect the beam 106. Although various portions of the beam 106 can have different deflection angles 214, the COM associated with the power of the beam 106 can be associated with this additional wavelength λ4.

[0077] Referring generally to Figures 4A to 4C , it should be understood that Figures 4A to 4C and the associated description is provided for illustrative purposes only and should not be interpreted as limiting. Rather, the spectrally distributed sampled beam 120 can have any distribution across the detector 124.

[0078] Referring again to Figure 1A , the optical scanner 100 can include any type of detector 124 suitable for determining the COM of the spectrally distributed sampled beam 120.

[0079] In some embodiments, the detector 124 includes a multi-pixel sensor array, such as but not limited to a line sensor for ID measurements or an area sensor for 2D measurements. For example, the detector 124 can be formed as but is not limited to a complementary metal-oxide-semiconductor (CMOS) sensor, a charge-coupled device (CCD), or a single-pixel photodiode array. The COM of the spectrally distributed sampled beam 120 can be determined using any suitable technique. For example, each pixel can correspond to a range of wavelengths of the sampled beam 120 such that the COM can be determined based on the signal amplitudes of the various pixels.

[0080] In some embodiments, the detector 124 includes a position sensitive sensor, such as but not limited to a segmented sensor or a lateral effect photodiode. For example, a segmented sensor can include one or more pixels in each of two or more segments. In this way, the COM of the incident light can be determined from the relative ratio of the signals in each segment. As an illustration, a segmented sensor having two segments distributed along the dispersion direction 302 can provide a unidirectional measurement of the COM along the dispersion direction 302. As another illustration, a segmented sensor having four segments arranged as quadrants can provide a bidirectional measurement and can be adapted, but is not limited to, to account for misalignment between the detector 124 and the dispersive element 122. By way of another example, a lateral effect photodiode can include a single extended photodiode element having multiple contacts, where the COM of the incident light can be determined based on the relative signals from the multiple contacts.

[0081] It is considered herein that, due to the relatively small number of pixels and / or readout efficiency, a position sensitive sensor can generally provide faster readout times than a multi-pixel sensor array. Accordingly, a position sensitive sensor can enable a relatively faster sampling rate of the sampled beam 120 and thus a relatively faster correction of the frequency of the drive signal 116 compared to a multi-pixel sensor array. However, a multi-pixel sensor array can provide a more accurate measurement of the spectral distribution of the sampled beam 120 compared to a position sensitive sensor. Accordingly, the optical scanner 100 can include any combination of a position sensitive sensor or a multi-pixel sensor array.

[0082] It is further considered herein that ID measurements can be sufficient to provide compensation of multiple AODs 108 along multiple scan axes. 2D measurements can be suitable for configurations in which the beam 106 is sampled after the AOD 108 and the frequency correction is done in a closed loop to return the COM to a 2D center on the imaged plane of the AOD 108 plane (e.g., after a beam sampler and optical relay).

[0083] In some embodiments, the optical scanner 100 and / or system 102 includes an adaptive optics element 134 that provides spatially adjustable control over different portions of the beam 106. For example, the adaptive optics element 134 may include, but is not limited to, a deformable mirror, a MEMS device, a spatial light modulator (SLM), or a piezoelectric mirror (or a pair of mirrors). The adaptive optics element 134 may be adapted to control any beam parameters, such as, but not limited to, beam size, beam divergence, or beam propagation direction.

[0084] The optical scanner 100 may include the adaptive optics element 134 at any suitable location. For example, such as Figures 1A to 1B As explained, the adaptive optics element 134 can be positioned in the path of the beam 106 after the AOD 108 to modify one or more properties of the beam 106 after being deflected by the AOD 108. Furthermore, the adaptive optics element 134 can be communicatively coupled to the controller 110, such that the controller 110 can provide a drive signal 136 to the adaptive optics element 134 to control one or more aspects of the adaptive optics element 134. For illustration, the controller 110 can adjust the drive signal 136 for the adaptive optics element 134 based on signals from any of the one or more detectors 124.

[0085] In some embodiments, the adaptive optics element 134 provides adjustable optical power. For example, the adaptive optics element 134 can operate as a lens with an adjustable focal length. In this way, the adaptive optics element 134 can provide adjustable optical power based on the spectrum of the beam 106 (e.g., as measured by the sampled beam 120). Furthermore, the adaptive optics element 134 can provide different optical power along two directions (e.g., along two scanning directions). In this way, the adaptive optics element 134 can operate as a cylindrical focusing element.

[0086] In this document, it has been carefully considered that various instabilities of beam 106 can lead to variations in the spot size and / or divergence of beam 106 after deflection by AOD 108. For example, in the case where beam 106 contains light at multiple wavelengths, different wavelengths will have different deflection angles 214 from AOD 108 (e.g., based on equation (1)). This can still be the case even if the frequency of the drive signal 116 for AOD 108 has been adjusted as previously described herein. Therefore, spectral variations in beam 106 can lead to varying beam divergence from AOD 108. As another example, different optical modes of light source 104 can produce beams 106 with different spot sizes, beam profiles, and / or divergences due to different mode profiles in light source 104. In this way, various aspects of beam 106 before AOD 108 can vary.

[0087] Accordingly, the optical power of adaptive optical element 134 can be adjusted (e.g., by drive signals 136 provided by controller 110) to provide consistent beam properties (e.g., divergence, beam size, beam profile, or the like) despite variations in beam 106.

[0088] By way of illustration, the optical power of adaptive optical element 134 can be adjusted based on signals from one or more detectors 124 to provide a collimated beam 106 despite variations in beam 106. By way of further illustration, in the context of system 102 described in Figure 1B

[0089] It is contemplated herein that controller 110 can utilize any type of detector 124 for modifying drive signals 136 to adaptive optical element 134. In some embodiments, controller 110 utilizes a multi-pixel sensor array (e.g., a line sensor, an array sensor, or the like) to utilize the additional information provided by such a sensor. For example, it can be desirable to adjust the optical power of adaptive optical element 134 based on the spectral width of sampled beam 120, which can affect the overall divergence of beam 106 from AOD 108 along a scan direction. Accordingly, the increased spectral resolution provided by a multi-pixel sensor array can facilitate a more sensitive measurement of the spectral width than a position sensitive detector. It should be understood, however, that this is merely illustrative and should not be construed as limiting. In some cases, controller 110 can utilize signals from a position sensitive detector to adjust drive signals 136 to adaptive optical element 134.

[0090] Referring again generally to Figure 1A and 1B various additional aspects of optical scanner 100 are described in greater detail in accordance with one or more embodiments of the present disclosure.

[0091] In some embodiments, optical scanner 100 includes one or more components adapted to monitor the performance of AOD 108. For example, thermal drift in AOD 108 can affect the refractive index of bulk material 204 and / or the modulation depth of diffraction grating 206 (e.g., the magnitude of the refractive index variation An that forms diffraction grating 206). Accordingly, thermal drift in AOD 108 can affect the diffraction efficiency of diffraction grating 206 and the power of beam 106 deflected by AOD 108.

[0092] Figure 5 ​is a simplified schematic of portions of an optical scanner 100 including an additional detector 502 for monitoring performance of the AOD 108 in accordance with one or more embodiments of the present disclosure. In particular, Figure 5 is Figure 2 variations such that the description associated with Figure 2 extends to 5.

[0093] In some embodiments, the optical scanner 100 includes at least one additional detector 502 to monitor power of at least one diffraction order of the light beam 106 produced by the AOD 108. For example, although the diffraction efficiency of the first order diffraction 210 by the AOD 108 is generally high, especially when operating under Bragg conditions, at least some power is generally provided in additional non-zero diffraction orders. For example, at least a few percent of the power of the light beam 106 can be provided as a second order diffraction 212 and / or an additional first order diffraction light beam 504 having an opposite sign from the first order diffraction 210 associated with the primary deflection of the light beam 106. For example, operation under Bragg conditions can provide a majority of the power of the light beam 106 as the first order diffraction 210 as described with respect to Figure 2 , where the first order diffraction 210 can be a +1 order diffraction or a -1 order diffraction based on a selected sign convention. However, it can be the case that at least some small portion of the power of the light beam 106 can be in an additional first order diffraction light beam 504 having an opposite sign.

[0094] It is contemplated herein that the additional non-zero diffraction orders can advantageously be physically separated from the main scan range (e.g., the main working window) to provide easy access and not detract from the power output of the AOD 108. In contrast, some alternative techniques for monitoring thermal drift of an AOD can require injecting an additional weak drive signal into the AOD to produce weak diffraction at different angles and tracking the stability of this weak diffraction. In some embodiments, this additional drive signal can not require a separate dispersive element 122, especially if this additional drive signal has a higher frequency than the drive signal 136. In this configuration, the detector 124 can be placed to capture dispersive light associated with diffraction from the grating produced by this additional drive signal (e.g., by the periodic acoustic waves produced by this additional drive signal).

[0095] The controller 110 can then be coupled to the additional detector 502 to monitor power in the associated non-zero diffraction order. For example, increased power in this non-zero diffraction order can be indicative of thermal drift of the AOD 108.

[0096] In cases where the optical beam 106 exhibits spectral variation, such spectral variation can further affect the power in one or more additional non-zero diffraction orders. In these cases, the controller 110 can isolate the relative impact of thermal drift of the AOD 108 from the spectral variation based on signals from the one or more detectors 124. For example, spectral variation of the optical beam 106 can generally occur on a shorter timescale than thermal drift in the AOD 108. Thus, power variation of additional non-zero diffraction orders corresponding to observable spectral variation, as measured by the additional first order diffracted beam 504, can be removed or ignored by the controller 110, such that thermal drift in the AOD 108 on a relatively longer timescale can be monitored.

[0097] In some embodiments, the controller 110 is further configured to adjust an amplitude of the drive signal 116 to the AOD 108 based on signals from any of the one or more detectors 124. As described previously herein with respect to Figure 2 The amplitude of the drive signal 116 can control the modulation depth of the induced diffraction grating 206 and thus can control the diffraction efficiency of the optical beam 106. In this way, the controller 110 can adjust the intensity or power of the optical beam 106 deflected by the AOD 108.

[0098] In some embodiments, the controller 110 adjusts the amplitude of the drive signal 116 to provide the optical beam 106 with constant power. It is contemplated herein that the power of the optical beam 106 can fluctuate for various reasons. In any case, the controller 110 can adjust the amplitude of the drive signal 116 to provide the optical beam 106 with constant power over time.

[0099] For example, the power of the optical beam 106 from the light source 104 can fluctuate. Such power fluctuations can be detected using any suitable technique and provided to the controller 110. For example, power fluctuations of the sampled optical beam 120, which can include a fixed percentage of the power of the optical beam 106, can be monitored using any of the one or more detectors 124.

[0100] As another example, the power of the optical beam 106 deflected by the AOD 108 can vary based on thermal drift of the AOD 108, which can be detected using the additional first order diffracted beam 504 as described with respect to Figure 5

[0101] As another example, the power of the optical beam 106 propagates through a wavelength sensitive polarizing element (e.g., a polarization rotator, a polarizer, a polarizing beam splitter, or the like) in response to spectral variation of the optical beam 106. Such power fluctuations can be monitored by an additional detector (not shown) and / or can be predicted based on a known wavelength response of the element and spectral variation of the optical beam 106 as measured by the one or more detectors 124.

[0102] Again with reference to​Figures 1A to 1B It is contemplated herein that the controller 110 can use any technique known in the art to produce any adjustment described herein (e.g., a frequency and / or amplitude of the drive signal 116 for the AOD 108, a drive signal 136 for the adaptive optical element 134, or the like).

[0103] In some embodiments, the controller 110 uses a model and / or a model-based lookup table to produce the adjustment. As a non-limiting example, in the context of producing a frequency adjustment (Af) of the drive signal 116 in response to a spectral variation of the sampled light beam 120, a relationship between a COM of the spectrally dispersed sampled light beam 120 in the plane of the detector 124 and an associated spectral variation can be determined based on a dispersion of the dispersive element 122 and a separation between the dispersive element 122 and the detector 124. Thus, the controller 110 can directly calculate a required frequency adjustment (Af) based on the signal from the detector 124 or can use a lookup table containing previously calculated values.

[0104] In some embodiments, the controller 110 uses a control loop (e.g., a PID control loop or the like) or a machine learning-based technique to produce the adjustment.

[0105] In this configuration, the optical scanner 100 (and / or the system 102) can include one or more detectors (not explicitly shown) for monitoring a particular property of the light beam 106 as feedback. Furthermore, an exact relationship between the parameter to be adjusted and the feedback is not required. Rather, the feedback is used to actively control and / or predict a required adjustment. As a non-limiting example, in the context of producing a frequency adjustment (Af) of the drive signal 116, feedback from a detector monitoring a position of the light beam 106 after being deflected by the AOD 108 can provide feedback suitable for controlling a value of the frequency adjustment (Af). As another non-limiting example, in the context of adjusting a power of the light beam 106, feedback from a detector monitoring a power of the light beam 106 at a desired position can provide feedback suitable for controlling an amplitude of the drive signal 116. As another non-limiting example, in the context of adjusting a spot size of the light beam 106 (e.g., on the sample 128 depicted in FIG. 1), a detector monitoring the spot size can provide feedback suitable for adjusting the drive signal 136 to the adaptive optical element 134. Figure 1B

[0106] Reference is now made to Figure 6 , Figure 6 ​is a flowchart illustrating steps performed in a method 600 for dynamic control of an optical scanner, in accordance with one or more embodiments of the present disclosure. Applicant notes that embodiments and implementation techniques previously described herein in the context of the optical scanner 100 should be interpreted to extend to the method 600. However, it is further noted that the method 600 is not limited to the architecture of the optical scanner 100.

[0107] In some embodiments, the method 600 includes a step 602 of generating a sampled light beam 120 from the received light beam 106, wherein the sampled light beam 120 includes a portion of the light beam 106. For example, the step 602 can be implemented with a sampler 118 such as, but not limited to, an optical wedge or a beam splitter.

[0108] In some embodiments, the method 600 includes a step 604 of spectrally dispersing the sampled light beam 120 along a dispersion direction 302. For example, the step 604 can be implemented with a dispersive element 122 such as, but not limited to, a prism or a diffraction grating.

[0109] In some embodiments, the method 600 includes a step 606 of detecting at least a portion of the sampled light beam 120 dispersed along the dispersion direction 302 with one or more detectors 124.

[0110] In some embodiments, the method 600 includes a step 608 of determining a centroid of the sampled light beam 120 dispersed along the dispersion direction 302 based on a signal from at least one of the one or more detectors 124.

[0111] In some embodiments, the method 600 includes a step 610 of generating a drive signal 116 for the AOD 108 to deflect the light beam 106 along a selected deflection angle 214 based on the centroid. Further, in the case of multiple AODs 108 (e.g., providing different scanning directions), a drive signal 116 can be generated for each of the AODs 108. The drive signals 116 for these AODs 108 can be the same in the case that they operate at the same frequency, or can be different in the case that they operate at different frequencies. For example, operation at different frequencies can be suitable for addressing a particular portion of the total 2D field of view.

[0112] In some embodiments, the method 600 includes a step 612 of deflecting the light beam 106 with the AOD 108 driven by the drive signal 116.

[0113] The subject matter described herein is sometimes illustrated using different components within other components or connected to other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermediate components. Likewise, any two components so associated can also be viewed as being "connected" or "coupled" to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "couplable" to each other to achieve the desired functionality. Specific examples of couplable include but are not limited to physically interactable and / or physically interacting components and / or wirelessly interactable and / or wirelessly interacting components and / or logically interactable and / or logically interacting components.

[0114] It is believed that the disclosure and many of its attendant advantages will be understood by the foregoing description, and it will be apparent that various changes can be made in the form, construction and arrangement of the components without departing from the disclosed subject matter or without sacrificing all of its materials advantages. The form described is merely exemplary and it is intended to encompass and guide the scope of the appended claims.

Claims

1. An optical scanner, comprising: A sampler for receiving a light beam and providing a sampled light beam containing a portion of the light beam; A dispersive element used to cause the sampled beam to spectrally disperse along the dispersive direction; One or more detectors configured to receive at least a portion of the sampled beam dispersed along the dispersion direction; One or more acousto-optic deflectors (AODs) configured to deflect the light beam from the sampler; and A controller communicatively coupled to at least one or more AODs and one or more detectors, the controller comprising one or more processors configured to execute program instructions to cause the one or more processors to: The centroid of the sampled beam dispersed along the dispersion direction is determined based on signals from at least one of the one or more detectors. and A drive signal is generated for at least one of the one or more AODs to cause the beam from the sampler to deflect along a selected deflection angle based on the centroid.

2. The optical scanner of claim 1, wherein generating the drive signal comprises: Based on the expected value of the centroid associated with the expected wavelength of the sampled beam, a first frequency of the drive signal used to provide the selected deflection angle is calculated; The frequency adjustment is calculated based on the deviation of the centroid of the sampled beam dispersed along the dispersion direction from the expected value of the centroid; and The drive signal having a second frequency is generated based on the first frequency and the adjusted frequency.

3. The optical scanner of claim 1, wherein the one or more detectors comprise a position-sensitive sensor.

4. The optical scanner according to claim 3, wherein the position-sensitive sensor comprises: A segmented sensor having two or more segments, wherein the centroid can be determined based on the relative intensity of the sampled beam in the two or more segments.

5. The optical scanner of claim 4, wherein the segmented sensor comprises two segments distributed along the dispersion direction, wherein the centroid can be determined based on the relative intensity of the sampled beam in the two segments.

6. The optical scanner of claim 4, wherein the segmented sensor comprises four segments arranged in quadrants, wherein the centroid can be determined based on the relative intensity of the sampled beam in the four segments.

7. The optical scanner of claim 1, wherein the one or more detectors comprise a multi-pixel sensor array.

8. The optical scanner of claim 7, wherein the multi-pixel sensor array comprises: A linear array sensor comprising rows of individual pixels distributed along the dispersion direction.

9. The optical scanner of claim 7, wherein the multi-pixel sensor array comprises: A region array sensor comprising two or more rows of pixels, each row containing pixels distributed along the dispersion direction.

10. The optical scanner of claim 1, further comprising: An adaptive optics element having adjustable optical power, wherein the adaptive optics element is configured to receive the light beam from the one or more AODs, wherein the program instructions are further configured to cause the one or more processors to: Additional drive signals are generated for the adaptive optics element to control the optical power.

11. The optical scanner of claim 10, wherein generating the additional drive signal for the adaptive optics element to control the optical power comprises: The additional drive signal for the adaptive optics element is generated to control the optical power to collimate the beam.

12. The optical scanner of claim 10, wherein generating the additional drive signal for the adaptive optics element to control the optical power comprises: The additional drive signal for the adaptive optics element is generated to control the optical power and provide the focused spot size of the beam when focused with at least one of the adaptive optics element or an additional focusing element.

13. The optical scanner of claim 10, wherein generating the additional drive signal for the adaptive optics element to control the optical power comprises: The additional drive signal for the adaptive optics element is generated to control the optical power based on the centroid.

14. The optical scanner of claim 10, wherein generating the additional drive signal for the adaptive optics element to control the optical power comprises: The additional drive signal for the adaptive optics element is generated based on a signal from at least one of the one or more detectors to control the optical power based on the width of the sampled beam dispersed along the dispersion direction.

15. The optical scanner of claim 1, further comprising: A wavelength-sensitive polarizing optics device, in the path of the light beam, wherein the program instructions are further configured to cause the one or more processors to: The amplitude of the drive signal is adjusted based on the centroid to provide a selected power for the beam from the wavelength-sensitive polarizing optics and the one or more AODs.

16. The optical scanner of claim 1, further comprising: An additional detector configured to receive at least a portion of additional diffraction orders of the beam from the one or more AODs; The program instructions are further configured to cause the one or more processors to: The thermal drift of the one or more AODs is monitored based on the power of the additional diffraction order.

17. The optical scanner of claim 16, wherein the program instructions further cause the one or more processors to: The power of the additional diffraction order is compared with the centroid; and Based on the centroid, the thermal drift of the one or more AODs is isolated from the spectral variations of the sampled beam.

18. The optical scanner of claim 1, wherein the sampler, the dispersive element, and the one or more AODs are configured to operate at wavelengths in the range of 9 to 12 micrometers.

19. A system for optical scanning, comprising: A light source, configured to produce a beam of light; Scanners, including: A sampler for receiving the light beam and providing a sampled light beam containing a portion of the light beam; A dispersive element used to cause the sampled beam to spectrally disperse along the dispersive direction; One or more detectors configured to receive at least a portion of the sampled beam dispersed along the dispersion direction; One or more acousto-optic deflectors (AODs) configured to deflect the light beam from the sampler; A controller communicatively coupled to at least one or more AODs and one or more detectors, the controller comprising one or more processors configured to execute program instructions to cause the one or more processors to: The centroid of the sampled beam dispersed along the dispersion direction is determined based on signals from at least one of the one or more detectors; and Generate a drive signal for at least one of the one or more AODs to cause the beam from the sampler to deflect along a selected deflection angle based on the centroid; and One or more focusing optics configured to focus the beam deflected by the one or more AODs onto the sample.

20. The system of claim 19, wherein the light source comprises: CO2 laser source.

21. The system of claim 20, wherein the light beam has a wavelength in the range of 9 to 12 micrometers, wherein the sampler, the dispersive element, and the one or more AODs are configured to operate at wavelengths in the range of 9 to 12 micrometers.

22. The system of claim 19, wherein generating the drive signal comprises: Based on the expected value of the centroid associated with the expected wavelength of the sampled beam, a first frequency of the drive signal used to provide the selected deflection angle is calculated; The frequency adjustment is calculated based on the deviation of the centroid of the sampled beam dispersed along the dispersion direction from the expected value of the centroid; and The drive signal having a second frequency is generated based on the first frequency and the adjusted frequency.

23. The system of claim 19, wherein the one or more detectors comprise position-sensitive sensors.

24. The system of claim 23, wherein the position-sensitive sensor comprises: A segmented sensor having two or more segments, wherein the centroid can be determined based on the relative intensity of the sampled beam in the two or more segments.

25. The system of claim 24, wherein the segmented sensor comprises two segments distributed along the dispersion direction, wherein the centroid can be determined based on the relative intensity of the sampled beam in the two segments.

26. The system of claim 24, wherein the segmented sensor comprises four segments arranged in quadrants, wherein the centroid can be determined based on the relative intensity of the sampled beam in the four segments.

27. The system of claim 19, wherein the one or more detectors comprise a multi-pixel sensor array.

28. The system of claim 27, wherein the multi-pixel sensor array comprises: A linear array sensor comprising rows of individual pixels distributed along the dispersion direction.

29. The system of claim 27, wherein the multi-pixel sensor array comprises: A region array sensor comprising two or more rows of pixels, each row containing pixels distributed along the dispersion direction.

30. The system of claim 19, further comprising: An adaptive optics element having adjustable optical power, wherein the adaptive optics element is configured to receive the light beam from the one or more AODs, wherein the program instructions are further configured to cause the one or more processors to: Additional drive signals are generated for the adaptive optics element to control the optical power.

31. The system of claim 30, wherein generating the additional drive signal for the adaptive optics element to control the optical power comprises: The additional drive signal for the adaptive optics element is generated to control the optical power to collimate the beam.

32. The system of claim 30, wherein generating the additional drive signal for the adaptive optics element to control the optical power comprises: The additional drive signal for the adaptive optics element is generated to control the optical power and provide the focused spot size of the beam when focused with at least one of the adaptive optics element or an additional focusing element.

33. The system of claim 30, wherein generating the additional drive signal for the adaptive optics element to control the optical power comprises: The additional drive signal for the adaptive optics element is generated to control the optical power based on the centroid.

34. The system of claim 30, wherein generating the additional drive signal for the adaptive optics element to control the optical power comprises: The additional drive signal for the adaptive optics element is generated based on a signal from at least one of the one or more detectors to control the optical power based on the width of the sampled beam dispersed along the dispersion direction.

35. The system of claim 19, further comprising: A wavelength-sensitive polarizing optics device, in the path of the light beam, wherein the program instructions are further configured to cause the one or more processors to: The amplitude of the drive signal for the AOD is adjusted based on the centroid to provide a selected power for the beam from the wavelength-sensitive polarizing optics and the AOD.

36. The system of claim 19, further comprising: An additional detector configured to receive at least a portion of additional diffraction orders of the beam from the AOD; The program instructions are further configured to cause the one or more processors to: The thermal drift of the AOD is monitored based on the power of the additional diffraction order.

37. The system of claim 36, wherein the program instructions further cause the one or more processors to: The power of the additional diffraction order is compared with the centroid; and Based on the centroid, the thermal drift of the AOD is isolated from the spectral variation of the sampled beam.

38. A method for optical scanning, comprising: A sampled beam is generated from a received beam, wherein the sampled beam comprises a portion of the beam; The sampled beam undergoes spectral dispersion along the dispersion direction; At least a portion of the sampled beam dispersed along the dispersion direction is detected using one or more detectors; The centroid of the sampled beam dispersed along the dispersion direction is determined based on signals from at least one of the one or more detectors. Generate a drive signal for the acousto-optic deflector (AOD) to deflect the beam along a selected deflection angle based on the centroid; and The beam is deflected by the AOD driven by the driving signal.

39. The method of claim 38, further comprising: Additional drive signals are generated for the adaptive optics element to collimate or focus at least one of the beams based on at least one of the centroid or the width of the sampled beam dispersed along the dispersion direction.

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