Dynamic correction for acousto-optic deflectors

Abstract

An optical scanner may include a sampler for receiving a light beam and providing a sampled light beam including a portion of the light beam; a dispersion element for spectrally dispersing the sampled light beam along a dispersion direction; one or more detectors for receiving 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 may determine a center of mass of the sampled 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 AOD, the beam of light from the sampler is deflected along a selected deflection angle based on the centroid.

Description

Technical Field

[0001] The present disclosure relates generally to a beam scanner, and more particularly to dynamic correction of the beam scanner in the presence of spectral variations of the scanned beam. Background Art

[0002] Acoustic optical deflectors (AODs) can be used as beam scanning devices in a wide range of applications. AODs advantageously provide relatively fast scanning speeds but are sensitive to spectral variations of the scanned beam. Therefore, it would be desirable to develop systems and methods for addressing the above-mentioned deficiencies. Summary of the invention

[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 light beam and providing a sampled light beam including a portion of the light beam. In another illustrative embodiment, the optical scanner includes a dispersive element for spectrally dispersing the sampled light 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 light beam dispersed along the dispersion direction. In another illustrative embodiment, the optical scanner includes one or more acousto-optic deflectors (AODs) for deflecting the light beam from the sampler. In another illustrative embodiment, the optical scanner includes a controller. In another illustrative embodiment, the controller determines the 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.

[0004] According to one or more illustrative embodiments of the present 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 for receiving the light beam and providing a sampled light beam including a portion of the light beam; a dispersive element for spectrally dispersing the sampled light beam along a dispersion direction; one or more detectors for receiving at least a portion of the sampled light beam dispersed along the dispersion direction; and one or more acousto-optic deflectors (AODs) for deflecting the light beam from the sampler. In another illustrative embodiment, the system includes a controller. In another illustrative embodiment, the controller determines the 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 present disclosure, a method is disclosed. In one illustrative embodiment, the method includes generating a sampled beam from a received beam, wherein the sampled beam includes a portion of the beam. In another illustrative embodiment, the method includes spectrally dispersing the sampled beam along a dispersion direction. In another illustrative embodiment, the method includes using one or more detectors to detect at least a portion of the sampled beam dispersed along the dispersion direction. In another illustrative embodiment, the method includes determining the 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 method includes generating a drive signal for an acousto-optic deflector (AOD) to deflect the beam along a selected deflection angle based on the centroid. In another illustrative embodiment, the method includes using the AOD driven by the drive signal to deflect the beam.

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

[0007] Those skilled in the art may better appreciate the numerous advantages of the present disclosure by referring to 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 diagram of an acousto-optic deflector (AOD) according to one or more embodiments of the present disclosure.

[0011] Figure 3 is a graph 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 diagram of a first spectrally dispersed sampled light beam including a single lobe associated with a first wavelength in accordance with one or more embodiments of the present disclosure.

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

[0014] Figure 4C is a simplified conceptual schematic diagram 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 in accordance with one or more embodiments of the present disclosure.

[0015] Figure 5 is a simplified schematic diagram of a portion of an optical scanner including additional detectors for monitoring the performance of an AOD in accordance with one or more embodiments of the present disclosure.

[0016] Figure 6 is a flow chart 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 illustrated in the accompanying drawings. The present disclosure has been particularly shown and described with respect to specific embodiments and specific features thereof. The embodiments set forth herein are to be regarded as illustrative and not restrictive. It will be readily apparent to one of ordinary skill in the art that various changes and modifications in form and details may be made without departing from the spirit and scope of the present 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 (eg, 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 drive signal to the AOD, wherein the drive signal is 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 may include one or more transducers for generating acoustic waves in a host material, wherein driving the transducers with a periodic drive signal may form a diffraction grating in the host material. In this way, an incident light beam may be redirected via diffraction, wherein the deflection angle of the light beam from the AOD (e.g., the diffraction angle from the diffraction grating) may be controlled based on the frequency of the drive signal, and the intensity of the light beam from the AOD may be controlled based on the amplitude of the drive signal.

[0021] It is contemplated herein that such an AOD may advantageously provide scanning speeds higher than mechanical scanners (e.g., galvomirrors, rotating polygons, or the like), but may be highly sensitive to spectral variations of the scanned light beam. Specifically, spectral variations of the light beam may result in variations in the diffraction angle of the light beam by the AOD and, therefore, variations in the deflection angle of the light beam. However, the systems and methods disclosed herein may allow for dynamic compensation of spectral variations to provide fast and accurate optical scanning using the 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 polarized optics. Some polarized optics may provide non-uniform performance (e.g., transmittance and / or reflectivity) for different wavelengths. In this case, when such wavelength-sensitive polarized optics are used in an optical scanner, spectral variations of the light beam may result in power fluctuations. In some embodiments, the controller may further dynamically adjust the amplitude of the drive signal to the AOD to adjust the power of the light beam leaving the AOD and thereby compensate for power fluctuations associated with the interaction with the wavelength-sensitive polarized optics. Such wavelength-sensitive polarized optics may be placed before or after the AOD.

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

[0024] Reference Figures 1A to 6 , according to one or more embodiments of the present disclosure, systems and methods for performing optical scanning in the presence of spectral variations and / or beam size variations are described in more detail.

[0025] Figure 1A is a block diagram of an optical scanner 100 according to one or more embodiments of the present disclosure. Figure 1B is a block diagram of a system 102 including an optical scanner 100 according to 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 AOD 108 for controlling a 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 maintained 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 direct or otherwise control the AOD 108 based on the drive signal 116 to direct the light beam 106 along a specific deflection angle, a 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 of the light beam 106 and provide a consistent deflection angle of the light beam 106 through the AOD 108. For example, the optical scanner 100 can monitor spectral variations of the light beam 106 by: using a sampler 118 to sample a portion of the light beam 106 to form a sampled light beam 120; using a dispersion element 122 to spectrally disperse the sampled light beam 120; and using one or more detectors 124 coupled to the controller 110 to collect at least a portion of the spectrally dispersed sampled light beam 120.

[0027] In addition, although Figure 1A 108. Although not explicitly shown in the optical scanner 100, 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 light 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 light beam 106 and provide a consistent deflection angle of the light beam 106 through each AOD 108. In this way, any description of the operation or correction of the AOD 108 herein can be extended to apply to multiple AODs 108.

[0028] The one or more processors 112 of the controller 110 may include any processor or processing element known in the art. In this sense, the one or more processors 112 may include any microprocessor-type device configured to execute algorithms and / or instructions. For the purposes of this disclosure, the term "processor" or "processing element" may 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 may include any device configured to execute algorithms and / or instructions (e.g., program instructions stored in a memory). In some embodiments, the one or more processors 112 may be embodied as a desktop computer, a mainframe computer system, a workstation, an image computer, a parallel processor, a networked computer, or any other computer system configured to execute a program (which is configured to operate the optical scanner 100 or operate in conjunction with the optical scanner 100), as described in each of the present disclosures. In addition, the different subsystems of the optical scanner 100 may include processors or logic elements suitable for implementing at least part of the steps described in the present disclosure. Therefore, the above description should not be interpreted as a limitation on the embodiments of the present disclosure but is merely illustrative. In addition, the steps described in each place of the present disclosure may be implemented by a single controller or alternatively multiple controllers. In addition, the controller 110 may include one or more controllers housed in a common housing or in multiple housings. In this way, 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 may include any storage medium known in the art suitable for storing program instructions that can be executed by the associated one or more processors 112. For example, the memory 114 may include a non-transitory storage medium. By way of another example, the memory 114 may include, but is not limited to, a read-only memory (ROM), a random access memory (RAM), a magnetic or optical storage device (e.g., a disk), a tape, a solid-state drive, and the like. It should be further noted that the memory 114 may be housed in a common controller housing with the one or more processors 112. In some embodiments, the memory 114 may 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 may access a remote memory (e.g., a server) that is accessible via a network (e.g., the Internet, an intranet, and the like).

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

[0031] The optical scanner 100 may be integrated into any suitable system for dynamic beam steering. As an illustration, Figure 1B An optical scanner 100 is depicted for use in a system 102 suitable for material processing. In some embodiments, the system 102 includes a stage 126 for holding a sample 128. In some embodiments, the system 102 includes one or more focusing optics 130 for focusing a 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 pattern, wherein the AOD 108 within the optical scanner 100 is 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 may include any number or type of focusing optics suitable for focusing the light beam 106 onto the sample 128. In some embodiments, the focusing optics 130 include an F-theta lens to provide consistent focusing of the light beam 106 across the flat plane and a linear displacement across the sample 128 that varies as a function of the input angle (e.g., associated with the deflection angle of the light beam 106 from the optical scanner 100).

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

[0034] The system 102 may further include any number of additional optical devices, such as, but not limited to, optical relays, beam expanders, polarizers, spectral filters, spatial filters, or apodizers, for controlling various aspects of the light beam 106. Although not explicitly illustrated, such additional optical devices may be distributed at any suitable locations 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 of portions of the light beam 106. In this manner, properties such as, but not limited to, beam size, beam divergence, or focal properties of the light beam 106 deflected by the AOD 108 may be adjusted to provide consistent performance despite variations in the light beam 106. For example, the adaptive optical element 134 may be used within the system 102 to provide a consistent focused spot size on the sample 128 despite variations in the light beam 106.

[0036] Now generally refer to Figure 1A , various aspects of the optical scanner 100 are described in more detail according to one or more embodiments of the present disclosure.

[0037] Light beam 106 may include light of one or more selected wavelengths, including but not limited to ultraviolet (UV) radiation, visible radiation, or infrared (IR) radiation. In addition, light beam 106 from light source 104 may 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 may 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 may be integrated into the optical scanner 100, the system 102, or as an external component. In some embodiments, the light source 104 includes a narrow-band laser source that provides light centered at 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 CO2 laser can provide a light beam 106 having a wavelength in the range of 9 to 12 nanometers, but this is intended to be illustrative and not limiting.

[0040] The AOD 108 may include any type of deflector known in the art suitable for controlling the deflection angle of the light beam 106 via diffraction of acoustic waves through a material. Figure 2 is a simplified schematic diagram of the AOD 108 according to one or more embodiments of the present disclosure.

[0041] In some embodiments, AOD 108 includes at least one transducer 202 coupled to a body material 204. Body material 204 may include any type of material suitable for interacting with light beam 106, such as, but not limited to, glass or crystal. For example, body material 204 may be transparent to light beam 106. As an illustration, body material 204 may have an absorptivity below a selected threshold for wavelengths associated with light beam 106, and / or may have a transmittance above a selected threshold for wavelengths associated with light beam 106.

[0042] Transducer 202 may be any component suitable for generating acoustic waves in body material 204. In some embodiments, transducer 202 is a piezoelectric material that can expand or contract in response to an applied voltage (eg, drive signal 116), which can generate acoustic waves in body 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 bulk material 204, which may operate as a diffraction grating 206 adapted to diffract the light beam 106. In particular, the periodic distribution of acoustic waves may provide a periodic distribution of refractive index in the bulk material 204 operating as the diffraction grating 206.

[0044] Diffraction of the light beam 106 by the diffraction grating 206 may 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 diffraction order may 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 into first order diffraction 210 (e.g., +1st order diffraction or -1st order diffraction). Thus, the first order diffraction 210 may represent the deflected light beam 106, and the deflection angle 214 of the light beam 106 from the AOD 108 may correspond to the first order diffraction angle 216.

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

[0046] d(sinθ i -sinθ m )=mλ (1)

[0047] Where d is the period of the diffraction grating 206, m is the diffraction order, λ is the wavelength of the light beam 106, θ i is the incident angle of the light beam 106, and θ m is the diffraction angle of the associated diffraction order of the beam 106. Therefore, the first order diffraction angle 216 is

[0048] θ1=asin(sinθ i -λ\d) (2) and varies based on the wavelength (λ) of the light beam 106 and the period (d) of the diffraction grating 206. More generally, equation (1) states that the non-zero diffraction orders, including but not limited to the first order diffraction 210, are spectrally dispersed such that the diffraction angle θ m Varies based on the wavelength (λ) of the light beam 106 .

[0049] The power of the first order diffraction 210, and therefore the efficiency of the AOD 108 for deflecting the light beam 106, may depend on various factors, including, but not limited to, the magnitude of the variation in the refractive index of the host material 204 associated with the diffraction grating 206 (Δn, where n is the refractive index of the host material 204), which may be referred to as the modulation depth of the diffraction grating 206. In the AOD 108, this modulation depth (Δn) may be based on the amplitude of the acoustic wave generated 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 may be varied within a scan range (e.g., a travel window) by adjusting the frequency of the drive signal 116. The period (d) of the diffraction grating 206 may be inversely related to the frequency of the drive signal 116. For example, the controller 110 may generate the drive signal 116 and may 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 may exhibit various instabilities, such as, but not limited to, instabilities in the spectrum or beam size of the light beam 106. In the case of a laser source, such instabilities may, but are not required to, be associated with mode hopping between different supported modes, each of which may have a different wavelength (e.g., a central wavelength).

[0052] Variations in the spectrum of the light beam 106 (e.g., associated with such instabilities of the light source 104 or more generally associated with any mechanism) may induce errors in the deflection angle of the light beam 106. Figure 2 , which are considered as non-limiting examples, spectral variations of the light beam 106 may affect the first-order diffraction angle 216 and thus the deflection angle 214 of the light beam 106 from the AOD 108 based on equations (1) and (2). Therefore, a shift in the wavelength (λ) of the light beam 106 from an expected value (e.g., due to spectral variations) may result in an error in the deflection angle 214 from the AOD 108.

[0053] Although such deflection angle errors can be avoided by using wavelength insensitive scanning techniques (e.g., mechanical techniques, such as but not limited to galvanometers or rotating polygons) or selecting a light source 104 with reduced spectral variation, such approaches are not always desirable. For example, mechanical beam scanning techniques generally may have slower positioning rates (e.g., scanning rates) and thus may limit the processing capabilities of the system. As another example, techniques that provide a beam 106 with high spectral stability may limit the achievable power of the beam 106. In other words, mode hopping (and associated spectral instability) may be a result of high power operation of some laser sources (e.g., but not limited to CO2 laser sources).

[0054] Thus, in some applications, it may 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 may be selected to provide a beam 106 having a selected power without regard to spectral instabilities and without sacrificing scanning speed or accuracy.

[0055] Reference again Figure 1A to 1B In some embodiments, the optical scanner 100 includes various components for compensating for spectral variations of the light 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 spectral variations of the sampled beam 120 and, therefore, spectral variations of the beam 106. The controller 110 can then adjust the drive signal 116 of the AOD 108 to compensate for the spectral variations of the beam 106 over time to provide an accurate deflection angle 214 of the beam 106 despite the spectral variations.

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

[0058] The dispersive element 122 may 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 dispersive element 122 (and the detector 124) may be an online or real-time spectrometer. For example, in the case of a diffraction grating, the dispersive element 122 may generate a plurality of diffraction orders based on equation (1), wherein non-zero diffraction orders are spectrally dispersed. In some embodiments, as described with respect to the diffraction grating 206 of the AOD 108, the dispersive 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 first order diffraction.

[0059] The dispersive element 122 may generally have any dispersion value. In some embodiments, the dispersive 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. As an illustration, the dispersive element 122 may include, but is not required to include, a diffraction grating having 150 lines per millimeter 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 graph of a spatially dispersed sampled beam 120 according to one or more embodiments of the present disclosure. In particular, Figure 3 The graph corresponds to a spatially dispersed sampled light beam 120 associated with a CO 2 laser and depicts light dispersed along a dispersion direction 302 .

[0061] The spectral variation of the light beam 106 may manifest in a variety of ways and may depend on the particular light source 104. In some embodiments, the light beam 106 may include power centered around a single wavelength (e.g., a single central wavelength), where this wavelength may shift over time. For example, this behavior may be associated with, but is not limited to, thermal variations in the light source 104. In some embodiments, such as Figure 3 , a light source 104 may generate a light beam 106 having a 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) may exist at any particular time, and the distribution of wavelengths may change over time (e.g., due to mode hopping).

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

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

[0064] The controller 110 may then provide a drive signal 116 to the AOD 108 using any technique suitable for compensating 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 the center of mass (COM) of the spectrally dispersed sampled light beam 120 and dynamically adjusts the frequency of the drive signal 116 to the AOD 108 based on the COM of the spectrally dispersed sampled light beam 120.

[0065] As an illustration, the controller 110 may calculate a first frequency (f0) of the drive signal 116. This first frequency may be selected 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 to provide a desired deflection angle 214 of the light beam 106.

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

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

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

[0069] It is contemplated herein that adjusting the frequency of the drive signal 116 based on deviations in the COM of the spectrally dispersed sampled light beam 120 may 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 every optical mode or at every specific wavelength of the sampled light beam 120. Rather, the COM of the spectrally dispersed sampled light beam 120 may provide an indicator of spectral variations in a manner that is related to compensation for the effects of spectral variations on the deflection angle 214.

[0070] For example, where the spectrum of the sampled beam 120 (and therefore the beam 106) includes power centered about a single central wavelength that is shifted over time, the COM of the sampled beam 120 may correspond to this central wavelength such that the frequency (f2) of the drive signal 116 may be adjusted to track this central wavelength.

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

[0072] As an illustration, Figures 4A to 4C Depicted are variations in the COM of the sampled light beam 120 in response to various spectral variations in accordance with one or more embodiments of the present disclosure. Figure 4A is a simplified conceptual schematic diagram of a first spectrally dispersed sampled light beam 120 including a single lobe 402 associated with a first wavelength (λ0) in accordance with one or more embodiments of the present disclosure. Figure 4B is a simplified conceptual diagram of a second spectrally dispersed sampled light beam 120 including a single lobe 404 associated with a second wavelength (λ1) in accordance with one or more embodiments of the present disclosure. Figure 4C is a simplified conceptual diagram of a third spectrally dispersed sampled light 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 present disclosure.

[0073] exist Figures 4A to 4C In FIG. 4 , lobes 402 to 408 each have a symmetrical power distribution (not illustrated) and the same physical size. Figure 4A and 4B In , lobes 402, 404 each contain the full power of sampled beam 120. Figure 4C, the power of the sampled light beam 120 is evenly distributed between the lobes 406 , 408 .

[0074] exist Figure 4A , the COM of the sampled beam 120 may correspond to the center of the lobe 402. Furthermore, the center of the lobe 402 may correspond to the physical center of the detector 124, which may correspond to the expected COM position (COM0). In this case, Figure 4A May correspond to a situation where compensation for the frequency of the drive signal 116 is not required.

[0075] exist Figure 4B , the COM of the spectrally distributed sampled light beam 120 may correspond to the center of the lobe 404. This may correspond to a simple shift of the central wavelength of the sampled light beam 120 relative to λ0 to λ1 and a corresponding COM shift (ΔCOM) of the spectrally distributed sampled light beam 120. Therefore, the controller 110 may provide a frequency adjustment (Δf) to compensate for the COM shift (ΔCOM).

[0076] exist Figure 4C , the COM of the spectrally distributed sampled light beam 120 may correspond to an additional wavelength λ4, where the sampled light beam 120 may or may not provide light at this wavelength. Figure 4C Two lobes at wavelengths λ2 and λ3 are illustrated, with the COM corresponding to an additional wavelength λ4 positioned between the two lobes. In any case, the specific wavelength λ4 may correspond to the COM of the spectral power distribution of the sampled light beam 120, and thus may provide a convenient wavelength to use as a basis for adjusting the frequency of the drive signal 116 to deflect the light beam 106. Although various portions of the light beam 106 may have different deflection angles 214, the COM associated with the power of the light beam 106 may be associated with this additional wavelength λ4.

[0077] Generally speaking Figures 4A to 4C , it should be understood that Figures 4A to 4C and the associated description are provided for illustrative purposes only and should not be construed as limiting. Rather, the spectrally distributed sampled light beam 120 may have any distribution across the detector 124.

[0078] Reference again Figure 1A , the optical scanner 100 may include any type of detector 124 suitable for determining the COM of the spectrally distributed sampled light 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 1D measurement or an area sensor for 2D measurement. For example, the detector 124 may be formed as, but 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 light beam 120 may be determined using any suitable technique. For example, each pixel may correspond to a wavelength range of the sampled light beam 120, such that the COM may be determined based on the signal amplitude of the various pixels.

[0080] In some embodiments, 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 may include one or more pixels in each of two or more segments. In this way, the COM of the incident light can be determined by the relative ratio of the signals in each segment. As an illustration, a segmented sensor with 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 with four segments arranged as quadrants can provide a bidirectional measurement and can be suitable for, but not limited to, accounting for misalignment between detector 124 and dispersion element 122. By way of another example, a lateral effect photodiode may include a single extended photodiode element with multiple contacts, wherein the COM of the incident light can be determined based on the relative signals from the multiple contacts.

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

[0082] It is further contemplated herein that 1D measurements may be sufficient to provide compensation for multiple AODs 108 along multiple scan axes. 2D measurements may be applicable to configurations where the beam 106 is sampled after the AOD 108 and frequency correction is done in a closed loop to return the COM to the 2D center on the imaged plane of the AOD 108 plane (e.g., after the beam sampler and optical relays).

[0083] In some embodiments, the optical scanner 100 and / or the system 102 include an adaptive optical element 134 that provides spatially adjustable control of different portions of the light beam 106. For example, the adaptive optical 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 mirror pair). The adaptive optical element 134 may be adapted to control any beam parameter, such as, but not limited to, beam size, beam divergence, or beam propagation direction.

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

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

[0086] It is contemplated herein that various instabilities of the light beam 106 may result in variations in the spot size and / or divergence of the light beam 106 after being deflected by the AOD 108. For example, where the light beam 106 includes light at multiple wavelengths, different wavelengths will have different deflection angles 214 (e.g., based on equation (1)) from the AOD 108. This may be the case even if the frequency of the drive signal 116 for the AOD 108 has been adjusted as previously described herein. Thus, variations in the spectrum of the light beam 106 may result in variations in the beam divergence from the AOD 108. As another example, it may be the case that different optical modes of the light source 104 may produce light beams 106 having different spot sizes, beam profiles, and / or divergences due to different mode profiles in the light source 104. In this way, various aspects of the light beam 106 before the AOD 108 may vary.

[0087] Thus, the optical power of the adaptive optical element 134 may be adjusted (eg, by a drive signal 136 provided by the controller 110 ) to provide consistent beam properties (eg, divergence, beam size, beam profile, or the like) despite variations in the beam 106 .

[0088] As an illustration, the optical power of the adaptive optical element 134 can be adjusted based on the signals from the one or more detectors 124 to provide the collimated light beam 106 despite the variations of the light beam 106. As another illustration, in Figure 1B In the context of the system 102 illustrated in , the optical power of the adaptive optical element 134 can be adjusted based on signals from one or more detectors 124 to provide a consistent focused spot size on the sample 128 (e.g., in conjunction with additional components such as focusing optics 130 or additional optics).

[0089] It is contemplated herein that the controller 110 may utilize any type of detector 124 for modifying the drive signal 136 to the adaptive optical element 134. In some embodiments, the 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 sensors. For example, it may be desirable to adjust the optical power of the adaptive optical element 134 based on the spectral width of the sampled light beam 120, which may affect the overall divergence of the light beam 106 from the AOD 108 along the scan direction. Thus, the increased spectral resolution provided by the multi-pixel sensor array may facilitate a more sensitive measurement of the spectral width than a position sensitive detector. However, it should be understood that this is merely illustrative and should not be construed as limiting. In some cases, the controller 110 may utilize a signal from a position sensitive detector to adjust the drive signal 136 to the adaptive optical element 134.

[0090] Now again, refer to Figure 1A and 1B , various additional aspects of the optical scanner 100 are described in more detail according to one or more embodiments of the present disclosure.

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

[0092] Figure 5is a simplified schematic diagram of a portion of an optical scanner 100 including an additional detector 502 for monitoring the performance of the AOD 108 in accordance with one or more embodiments of the present disclosure. In particular, Figure 5 yes Figure 2 The change of Figure 2 The associated description can be extended to 5.

[0093] In some embodiments, the optical scanner 100 includes at least one additional detector 502 to monitor the power of at least one diffraction order of the light beam 106 generated 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 the second order diffraction 212 and / or the additional first order diffraction beam 504 having an opposite sign to 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 described with respect to Figure 2 First order diffraction 210 is depicted, where first order diffraction 210 may be either +1st or -1st order diffraction based on a selected sign convention. However, it may be the case that at least some minor portion of the power of beam 106 may be in additional first order diffracted beam 504 of opposite sign.

[0094] It is contemplated herein that the additional non-zero diffraction orders may be advantageously physically separated from the main scanning range (e.g., the main operating window) to provide easy access without detracting from the power output of the AOD 108. In contrast, some alternative techniques for monitoring thermal drift of the AOD may 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 may 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 may be positioned to capture the dispersed light generated by this additional drive signal (e.g., by the periodic acoustic waves generated by this additional drive signal) associated with diffraction from the grating.

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

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

[0097] In some embodiments, the controller 110 is further configured to adjust the amplitude of the drive signal 116 to the AOD 108 based on the signal from any of the more than one detectors 124. Figure 2 As described, 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 light beam 106. In this way, the controller 110 can adjust the intensity or power of the light beam 106 deflected by the AOD 108.

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

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

[0100] As another example, the power of the beam 106 deflected by the AOD 108 may vary based on the thermal drift of the AOD 108, which may be measured using, for example, Figure 5 An additional first order diffracted beam 504 is described for detection.

[0101] As another example, the power of the light 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 variations of the light beam 106. Such power fluctuations may be monitored by additional detectors (not shown), and / or may be predicted based on the known wavelength response of the element and the spectral variations of the light beam 106 as measured by the one or more detectors 124.

[0102] Reference again Figure 1A to 1B It is contemplated herein that the controller 110 may use any technique known in the art to produce any of the adjustments described herein (e.g., the frequency and / or amplitude of the drive signal 116 for the AOD 108, the drive signal 136 for the adaptive optical element 134, or the like).

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

[0104] In some embodiments, the controller 110 generates the adjustments using a control loop (eg, a PID control loop or the like) or a machine learning based technique.

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

[0106] Reference Figure 6 , Figure 6is a flow chart illustrating the steps performed in a method 600 for dynamic control of an optical scanner according to one or more embodiments of the present disclosure. Applicants mention that the embodiments and implementation techniques previously described herein in the context of the optical scanner 100 should be interpreted as extending to the method 600. However, it should be further noted that the method 600 is not limited to the architecture of the optical scanner 100.

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

[0108] In some embodiments, method 600 includes step 604 of spectrally dispersing sampled light beam 120 along dispersion direction 302. For example, step 604 may 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 the selected deflection angle 214 based on the centroid. In addition, in the case of multiple AODs 108 (e.g., providing different scanning directions), a drive signal 116 may be generated for each of the AODs 108. The drive signals 116 of these AODs 108 may be the same if they operate at the same frequency, or may be different if they operate at different frequencies. For example, operation at different frequencies may be suitable for addressing specific portions of the total 2D field of view.

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

[0113] The subject matter described herein sometimes illustrates different components contained in or connected to other components. It should be understood that such depicted architectures are only exemplary, and in fact many other architectures that realize the same functionality can be implemented. In a conceptual sense, any component arrangement for realizing the same functionality is effectively "associated" so as to realize the desired functionality. Therefore, any two components combined to realize a specific functionality in this article can be regarded as "associated" with each other so as to realize the desired functionality, regardless of the architecture or intermediate components. Similarly, any two components so associated can also be regarded as "connected" or "coupled" to realize the desired functionality, and any two components that can be so associated can also be regarded as "coupleable" to each other to realize the desired functionality. Specific examples that can be coupled include but are not limited to physically interactable and / or physically interactive components and / or wirelessly interactive and / or wirelessly interactive components and / or logically interactive and / or logically interactive components.

[0114] It is believed that the present disclosure and its many attendant advantages will be understood from the foregoing description, and it will be appreciated that various changes may be made to the form, construction, and arrangement of components without departing from the disclosed objects or sacrificing all of their material advantages. The forms described are merely illustrative, and the appended claims are intended to cover and encompass such changes. Furthermore, it should be understood that the invention is defined by the appended claims.

Claims

1. An optical scanner, comprising: a sampler for receiving the light beam and providing a sampled light beam comprising a portion of the light beam; a dispersive element for spectrally dispersing the sampled light beam along a dispersion direction; one or more detectors configured 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 communicatively coupled to at least the one or more AODs and the one or more detectors, the controller comprising one or more processors configured to execute program instructions causing the one or more processors to: 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; and A drive signal is generated 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.

2. The optical scanner of claim 1 , wherein generating the drive signal comprises: calculating a first frequency of the drive signal for providing the selected deflection angle based on an expected value of the centroid associated with an expected wavelength of the sampled light beam; calculating an adjustment frequency based on a deviation of the centroid of the sampled light beam dispersed along the dispersion direction from the expected value of the centroid; and The driving signal having a second frequency is generated based on the first frequency and the adjustment frequency.

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

4. The optical scanner of claim 3, wherein the position sensitive sensor comprises: A segmented sensor having two or more segments, wherein the centroid is determinable based on relative intensities of the sampled light beams 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 is determinable based on relative intensities of the sampled light beams in the two segments.

6. The optical scanner of claim 4, wherein the segmented sensor comprises four segments arranged as quadrants, wherein the centroid is determinable based on relative intensities of the sampled light beams 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 line array sensor comprises individual rows of pixels distributed along the dispersion direction.

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

10. The optical scanner according to claim 1, further comprising: an adaptive optical element having adjustable optical power, wherein the adaptive optical 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: An additional drive signal for the adaptive optical element is generated to control the optical power.

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

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

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

15. The optical scanner according to claim 1, further comprising: a wavelength-sensitive polarizing optical device in a 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 of the light beam from the wavelength sensitive polarizing optics and the one or more AODs.

16. The optical scanner of claim 1, further comprising: additional detectors configured to receive at least portions of additional diffraction orders of the light beam from the one or more AODs; The program instructions are further configured to cause the one or more processors to: The one or more AODs are monitored for thermal drift based on the power of the additional diffraction orders.

17. The optical scanner of claim 1, wherein the program instructions further cause the one or more processors to: comparing the power of the additional diffraction order to the centroid; and Based on the centroid, the thermal drift of the one or more AODs is isolated from variations in the spectrum of the sampled light 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 a wavelength in the range of 9 to 12 microns.

19. A system comprising: a light source configured to generate a light beam; A scanner comprising: a sampler for receiving the light beam and providing a sampled light beam comprising a portion of the light beam; a dispersive element for spectrally dispersing the sampled light beam along a dispersion direction; one or more detectors configured 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; a controller communicatively coupled to at least the one or more AODs and the one or more detectors, the controller comprising one or more processors configured to execute program instructions causing the one or more processors to: 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; and generating 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; and One or more focusing optics configured to focus the light beam deflected by the one or more AODs onto a sample.

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

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

22. The system of claim 19, wherein generating the drive signal comprises: calculating a first frequency of the drive signal for providing the selected deflection angle based on an expected value of the centroid associated with an expected wavelength of the sampled light beam; calculating an adjustment frequency based on a deviation of the centroid of the sampled light beam dispersed along the dispersion direction from the expected value of the centroid; and The driving signal having a second frequency is generated based on the first frequency and the adjustment 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 is determinable based on relative intensities of the sampled light beams 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 is determinable based on relative intensities of the sampled light beams in the two segments.

26. The system of claim 24, wherein the segmented sensor comprises four segments arranged as quadrants, wherein the centroid is determinable based on relative intensities of the sampled light beams 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 line array sensor comprises individual rows of pixels distributed along the dispersion direction.

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

30. The system of claim 19, further comprising: an adaptive optical element having adjustable optical power, wherein the adaptive optical 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: An additional drive signal for the adaptive optical element is generated to control the optical power.

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

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

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

35. The system of claim 19, further comprising: a wavelength-sensitive polarizing optical device in a 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 of the light 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 light beam from the AOD; The program instructions are further configured to cause the one or more processors to: Thermal drift of the AOD is monitored based on the power of the additional diffraction order.

37. The system of claim 19, wherein the program instructions further cause the one or more processors to: comparing the power of the additional diffraction order to the centroid; and Based on the centroid, the thermal drift of the AOD is isolated from variations in the spectrum of the sampled light beam.

38. A method comprising: generating a sampled beam from the received beam, wherein the sampled beam comprises a portion of the beam; spectrally dispersing the sampled light beam along a dispersion direction; detecting, using one or more detectors, at least a portion of the sampled light beam dispersed along the dispersion direction; 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; generating a drive signal for an acousto-optic deflector (AOD) to deflect the light beam along a selected deflection angle based on the centroid; and The light beam is deflected using the AOD driven by the drive signal.

39. The method of claim 38, further comprising: An additional drive signal for an adaptive optical element is generated to collimate or focus at least one of the light beams based on at least one of the centroid or a width of the sampled light beam dispersed along the dispersion direction.

Images