[0001] This application claims priority to the provisional application with serial number 63/368,909 titled “SPECTRUM AND POLARIZATION PROGRAMMABLE LIGHT SOURCE,” filed July 20, 2022. The entire contents of the above noted provisional application are incorporated by reference as part of the disclosure of this document.

TECHNICAL FIELD

[0002] This description in this patent document relates to light sources that can produce light with changeable spectral and polarization characteristics.

BACKGROUND

[0003] Light sources that can generate outputs with changeable polarization states can be beneficial for many applications that utilize polarized light, including microscopy, imaging, LIDAR, surface and texture measurements, to name a few. In addition, it is advantageous to be able to control the spectral output of light sources, and to readily produce light within a particular spectral characteristics.

SUMMARY

[0004] The disclosed embodiments relate to programmable or adjustable light sources and associated methods that can be implemented in various embodiments to produce light having a desired spectrum and polarization state. The disclosed technology enables the production of an output light with customized spectral and polarization characteristics; these characteristics can be readily changed on-demand, such as by issuing commands that can be received by the various components of the light source to modify the spectral and polarization characteristics of the output light. The disclosed technology can be utilized to implement various devices, such as a tunable light source, a spectrum equalizer, a polarization compensator, a wavelength scanner, and/or a polarization state generator. Applications of the disclosed technology include, but are not limited to, telecommunication, 3D imaging, biomedical imaging, microscopy, remote sensing, ellipsometry, polarimetry and spectroscopy. [0005] One aspect of the disclosed embodiments relates to an adjustable light source apparatus that includes a dispersive element positioned to receive input light and to produce light having a plurality of spatially separated wavelength components, a digital micromirror device (DMD) including a plurality of micromirrors that are configured to operate in response to a first set of values. The DMD is positioned to receive the plurality of the spatially separated wavelength components and to modulate intensity of the plurality of the spatially separated wavelength components based on the first set of values. The adjustable light source also includes a polarizer positioned to receive light that is output from the DMD, and at least one pixelated spatial light modulator (SLM) configured to operate in response to at least a second set of values. The at least one pixelated SLM is positioned to receive polarized light from the polarizer and to impart a polarization change to the polarized light based on the second set of values. The DMD is configured to impart a particular spectral shape to the spectrally separated wavelength components based on the first set of values, the at least one pixelated SLM is operable, on a pixel-by-pixel basis, to move a polarization state of the polarized light incident on each pixel to another polarization state, and the first set of values and the second set of values are adjustable to enable customization of spectral and polarization characteristics of light that is output from the adjustable light source apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 illustrates an example output spectrum of a light source.

[0007] FIG. 2A illustrates an adjustable light source in accordance with an example embodiment.

[0008] FIG. 2B illustrates example orientations of the fast axes for the polarizer and the variable retarders of FIG. 2A.

[0009] FIG. 2C illustrates a Poincare sphere showing example transformations of the polarization state of light that propagates through the polarizer and variable retarders of FIG. 2B.

[0010] FIG. 2D illustrates an example configuration of a spatial light modulator with two sections and associated folded optics components that can be used for implementing a light source in accordance with an example embodiment. [0011] FIG. 3 illustrates an adjustable light source in accordance with another example embodiment.

[0012] FIG. 4 illustrates an adjustable light source in accordance with another example embodiment.

[0013] FIG. 5 illustrates an adjustable light source in accordance with another example embodiment.

[0014] FIG. 6 illustrates a block diagram of a system that includes an adjustable (or programmable) light source apparatus in accordance with an example embodiment.

[0015] FIG. 7 illustrates an adjustable light source that includes two adjustable light sources that cover an extended wavelength range in accordance with an example embodiment.

DETAILED DESCRIPTION

[0016] Some existing light sources can produce outputs that can be adjusted to produce a desired spectrum but, among other disadvantages, there is no or little control of the output polarization state of the light. The disclosed technology addresses this and other limitations of prior systems by integrating a broadband light source with a dispersive optical component, such as a grating or prism, an intensity control component, such as a digital micromirror device (DMD) and at least one spatial light modulator (SLMs) as components of a programmable light spectrum and polarization synthesis system. In some embodiments, the DMD controls the intensity of the different spectral components, whereas the SLM acts as a tunable waveplate to convert the different spectral components to different polarization states.

[0017] FIG. 1 illustrates an example output spectrum of a light source. This example spectrum can be divided into four spectral (or wavelength) components 101 , 102, 103 and 104. Each spectral component 101 , 102, 103 and 104 (spanning a range of frequency or wavelength values) has a different intensity profile and polarization state. As shown, spectral component 101 has circular polarization 111 ; spectral component 102 has linear polarization 112; spectral component 103 has elliptical polarization 113; and spectral component 104 has a different elliptical polarization 114 than elliptical polarization 113. [0018] One example embodiment of the light source is shown in FIG. 2A. Light from a broadband light source 201 is incident on a collimating lens 202. Examples of the input broadband light source include a xenon arc lamp, a laser-driven light source, a supercontinuum light source, an optical frequency comb, a light emitting diode (LED) array and/or a combination thereof. The ideal input light source has wide-spectrum (e.g., all of visible spectrum, all of IR spectrum, etc.), high power efficiency, small emitting area, low form factor, long lifetime and stable output. Example values are power efficiencies of greater than 10%, emitter area of 1 to 10 mm ² , form factor (excluding power supply) of 10 cm ³ , lifetime greater than 1500 hours and output stability of less than 0.5% per hour. The collimated light is reflected from a grating 203 which spatially separates the light into different wavelength components. The diffracted light with spatially separated wavelength components is incident on a DMD 204, which redirects the components onto a polarizer 205. The DMD controls the intensity of the spatially separated wavelength components and can therefore spectrally shape the light that is incident thereon by preferentially allowing certain wavelength components to be deflected in the desired direction with little or no loss. For example, assuming a rectangular array of micromirror devices, each column of the rectangular array can receive one wavelength component, and each individual mirror (e.g., pixel) in that column can controllably deflect the incident light (e.g., via deflecting or not deflecting the incident light in the desired direction) to modulate the intensity value. The individual mirrors of the pixeled array can be controlled based on, for example, an applied voltage to the DMD. It should be noted that in the above example, more than one column of the rectangular array may be configured to receive light associated with a particular wavelength component.

[0019] Referring back to FIG. 2A, light that is output from the DMD 204 reaches a polarizer 205, becomes polarized after passing through the polarizer 205 and is incident onto a pixelated SLM 206. The polarizer 205 can produce a linearly polarized light, for example. The SLM 206 can be a liquid crystal spatial light modulator. The SLM 206 acts as a variable retarder that modifies the polarization of the light that is incident thereon. The light that is incident on the SLM 206 has different wavelength components that are spatially separated and can have intensity variations that are imparted by the DMD. The light subsequently passes through a second pixelated SLM 207, which acts as a second variable retarder. For example, the first retarder can operate as a half wave plate for each wavelength component, and the second retarder can operate as a quarter wave plate for that wavelength component.

[0020] The variable retarder has a fast axis and a slow axis that are perpendicular to each other. When linearly polarized light propagates through a variable retarder, a phase shift is introduced to the light polarized in the fast axis, and a different phase shift is introduced to the light polarized in the slow axis. The retardance 5(7) is usually defined as the phase difference between the slow axis phase shift (the longer optical path length) and the fast axis phase shift (the shorter optical path length) and is a function of the applied voltage V (e.g., applied to the liquid crystal elements). The Mueller matrix of a linear retarder with fast axis at an angle 6 and retardance 6 is given by:

[0021] FIG. 2B illustrates example orientations of the fast axes (shown as hash lines) for the polarizer 205 and the variable retarders 206 and 207 of FIG. 2A. This configuration is capable of generating all polarization states. In this example configuration, unpolarized or partially polarized light 220B propagates through a linear polarizer 205B with transmission axis of 45° with respect to the fast axis of the variable retarder 206B and subsequently through the variable retarder 207B. The fast axis of the variable retarder 207B is at -45° with respect to the fast axis of the variable retarder 206B. The Stokes parameters of the linearly polarized light through the linear polarizer 205B are:

[0022] After propagation through the retarder 206B of retardance 5! and the retarder 207B of retardance 5 ₂ , the output Stokes parameters S _out becomes:

[0023] Geometrically, this is illustrated on the Poincare sphere in FIG. 2C. In this illustration, linearly polarized light at location 205C on the sphere is rotated to location 206C by retarder 206B about the axis. It is subsequently rotated to location 207C by retarder 207B about the S ₂ axis. By tuning the voltages and, thus, the retardances <5 _{1 2} , the combination of elements 205, 206 and 207 converts the spatially separated wavelength components that are received from the DMD 204 to any desired or to an arbitrary polarization state, i.e. , any location on the Poincare sphere.

[0024] Referring back to FIG. 2A, the light that is output from the second retarder 207 is then reflected from a second grating 208, which reverses the effect of the first grating 203 by combining the spatially separated wavelength components. In some embodiments, an additional achromatic wave plate is placed in the optical path between the gratings 203 and 208 to reduce polarization dependent loss (PDL). In the example configuration of FIG. 2A, the SLM’s 206 and 207 have the same number of pixels that are in alignment with each other. In some embodiments, relay optics, which is not shown in the figure, can be added to relay the light from, for example, SLM 206 onto SLM 207 while maintaining the same pixel-to-pixel correspondence between the SLMs 206 and 207. Light is collected by a lens 209 and can be coupled to an output optical fiber 210, for example. In some embodiments, the projected area of the pixels in the DMD 204 and SLMs 206, 207 is the same or, or the pixels in the two devices are an integer multiple of each other. The projected area depends on the tilt angle between the pixels. If the projected area of the pixels is different, additional magnification or de-magnification optics, which are not shown, may be placed between the DMD 204 and the SLM 206 and between SLM 206 and SLM 207.

[0025] The spectrum and polarization states of the output light can be tuned by adjusting the voltages for the pixels in the DMD 204 and the SLMs 206 and 207. For example, as explained earlier, individual pixels of the DMD 204 can be controlled via a first set of voltage values to implement a first spectral shape of the output light. The individual pixels of each of the SLM 206 and 207 can be controlled using a second and a third set of voltage values, respectively, to produce the desired output polarization states for the spectrally shaped light. By changing the first set of voltage values, the spectral shape of the output light can be changed. By changing the second and third set of voltage values, the output polarization characteristics of the spectrally shaped light can be modified.

[0026] It should be noted that in some embodiments, the order of operations (and thus the positioning of the components) may be changed to first impart the desired polarization characteristics by the SLMs, and then perform the spectral shaping by the DMD. That is the light with spectrally separated components is first received at the polarizer, onto the SLMs, and then to the DMD.

[0027] In some embodiments, only one SLM can be utilized instead of the two SLMs that are shown in FIG. 2A. For example, the pixels on the single SLM are divided into two parts: the first part is used as a tunable retarder similar to the way SLM 206 was used in FIG. 2A. The second part of the SLM is used as a tunable retarder similar to the way SLM 207 was used in FIG. 2A. In this case, light is first incident on the first part, and is subsequently incident on the second part after passing through a folded optics geometry and rotation. In this configuration, the spatial granularity or resolution is reduced. Alternatively, the size of the SLM can be enlarged to offset some or all of the lost resolution. FIG. 2D illustrates an example configuration, where the SLM includes two sections 206D-1 and 206D-2. The first section 206D-1 receives the polarized light 215D and operates as a first retarder as explained above. Four reflectors 211 D, 212D, 213D and 214D are used to direct the light that is output from the first section 206D-1 to the second section 206D-2 of the SLM, which operates as the second retarder. In this case, the changes in the polarization state due to reflectors 211 D, 212D, 213D and 214D are taken into account in the determination of the final polarization state.

[0028] Another example embodiment of the adjustable light source is shown in FIG. 3. Light from a broadband light source 301 is incident on a collimating lens 302. The collimated light passes through a transmission grating 303 which separates spatially the light into different wavelength components. The diffracted light having spatially separated wavelength components is incident on a DMD 304, which modulates the intensity of the spectrally separated wavelength components and redirects them onto a polarizer 305. As described in connection with FIG. 2A, the DMD 304 shapes the spectrum by controlling the intensity of the spatially separated wavelength components. The light that is received from the DMD 304 becomes polarized (linearly polarized) after passing through the polarizer 305 and is incident onto a pixelated SLM 306. For example, the SLM 306 can be a liquid crystal on silicon (LCoS) spatial light modulator. The SLM 306 acts as a variable retarder that rotates the polarization of the light as explained earlier. The light subsequently reflects from a second pixelated SLM 307, which acts as another variable retarder. Relay optics, not shown in the figure, can be placed in the light path to relay the light from SLM 306 to SLM 307. The SLM 307 can also be an LCoS spatial light modulator. The combination of elements 305, 306 and 307 converts the light having spatially separated wavelength components to any desired polarization state, similar to that discussed for FIG. 2A. The light is then incident on a second transmission grating 308, which reverses the effects of the first grating 303 by combining spatially the different wavelength components. Light is collected by a lens 309 and coupled to, for example, an output optical fiber 310. The spectrum and polarization states of the output light can be tuned by adjusting the voltages for the pixels in the DMD 304 and the SLMs 306 and 307.

[0029] In some embodiments, an additional achromatic wave plate can be placed in the optical path between the gratings 303 and 308 to reduce PDL. As evident from the comparison with FIG. 2A, the gratings 303 and 308 of FIG. 3 operate in transmission as opposed to their counterparts in FIG. 2A which operate in reflection. Conversely, the SLMs 306 and 307 operate in reflection as opposed to their counterparts in FIG. 2A which operate in transmission. In other implementations, the components can be positioned differently to operate in any combination of transmissive or reflective configurations.

[0030] In some embodiments, only one SLM can be utilized instead of two. For example, the pixels on a single SLM can be divided into two parts: the first part is used as a first tunable retarder and the second part is used as a second tunable retarder. In this case, polarized light is first incident on the first part and is subsequently incident on the second part after passing through a folded optics geometry and rotation.

[0031] FIG. 4 and FIG. 5 illustrate two example embodiments of the spectrum and polarization programmable light source. In these two configurations, a second grating is not used to reduce the degradation of the polarization states. Instead of using a second grating, a lens, 409 in FIG. 4 and 509 in FIG. 5, is used to focus the light to an output light guide, 410 in FIG. 4 and 510 in FIG. 5. The remaining components remain similar to those in prior figures. For example, FIGS. 4 and 5 each include a broadband light source 401/501 , a collimating lens 402/502, a grating 403/503, a DMD 404/504, SLMs 406/506 and 407/507, a polarizer 405/505 and a lens 409/509 that delivers the light to, for example, a fiber 410/510. In these configurations, the cost, weight and/or footprint of the device is also reduced, but the size of the output light beam is larger than that in the prior configurations. However, depending on the application, a smaller size of the beam (or a larger numerical aperture) may not be important or may be tolerated.

[0032] The programmable light source can be calibrated for different temperatures and humidity. In some implementations, the light source can be packaged in a fixed temperature and humidity container. The initial calibration includes the characterization of the polarizer, lens, grating, optical filter, DMD and SLM(s). For example, the wavelength and intensity distribution on each pixel of the DMD is measured and stored for different applied voltages. The Mueller matrices for the polarizer, lens, DMD and SLM(s) are also measured for light of different wavelength components and SLM applied voltages. The light source is then assembled to maximize the output spectrum and operating dynamic range. The Stokes parameters of the output light of the assembled light source is then measured by using a calibrated polarimeter for different wavelength components and applied voltages on the DMD and SLMs. In practical applications, the optical components, including the DMD and the SLMs, have polarization aberrations, such as diattenuation and retardance that are wavelength dependent and cannot be easily removed. The calibration process can determine the operating voltages that are needed for the generation of the desired output state of light, taking into account these polarization aberrations of the entire system.

[0033] FIG. 6 illustrates a block diagram of system 600 that includes an adjustable (or programmable) light source apparatus 602 in accordance with an example embodiment. The adjustable light source apparatus 602 receives input light from one of more optical light sources 601. A computation and/or control device 603 is communicatively coupled to the adjustable light source apparatus 602 and can provide the adjustable values to the components of the adjustable light source apparatus 602 as disclosed herein; the computation and/or control device 603 includes at least a processor and a memory, as disclosed herein. The adjustments, programming and/or any changes to the values may be made through a user interface 604, such as a keyboard, a mouse, voice prompts and the like. In some embodiments, the user interface 604 can communicate directly with the adjustable light source apparatus 602. In some embodiments, the user interface 604 is integrated as part of the computation and/or control device 603. In some embodiments, one of both of the user interface 604 and the computation and/or control device 603 are implemented as part of the adjustable light source apparatus 602. The output light from the adjustable light source apparatus 602 may be provided to a receiving device 605, such as an optical fiber, a camera, or another optical system.

[0034] In some embodiments, multiple adjustable/programmable light sources can be combined into a single instrument to cover a broad wavelength range. For example, a programmable light source designed to operate in the visible spectrum (380 nm to 750 nm) can be combined with a programmable light source designed to operate in the near infrared (NIR) (750 nm to 1 micron) and shortwave infrared (SWIR) (1 micron to 2.5 micron). The multiple programmable light sources can each utilize a different input light source, grating, polarizer, DMD and SLMs that are optimized to operate at their respective wavelength ranges. FIG. 7 shows one example configuration. Light 701 A from an input broadband light source 701 is split by a dichroic filter 702 into two spectral components 701 B and 701 C. The component 701 B passes through a programmable light source device 706 optimized for the spectral range of the spectral component 701 B and reflects off a mirror 704. The spectral component 701 C passes through another programmable light source device 707 optimized for the spectral range of the spectral component 701 C and reflects off a mirror 703. The reflected light from mirrors 703 and 704 are combined by a second dichroic filter 705 into output 701 D. The dichroic filter 702 is not needed if the separate input light sources are used.

[0035] The number of possible output states of light can be determined by the number of pixels in the DMD and the bit depth for the SLMs. As an example, the DMD can be a 100 by 100 array or 10,000 pixels, and each of the two SLMs can have an 8- bit depth or 256 states. In this example, the wavelength spectrum of the output light can have 100 components, and each component can have 100 different intensity values. The output light can have 256 by 256 or 65,536 different possible polarization states.

[0036] The control of DMDs and SLMs with individual element (pixel) granularity can be implemented based on voltage values. It is understood, however, that the DMDs and SLMs can be responsive to values that may represent current values, magnitude values, signed integer values, real numbers, analog values, or digital values, to name a few. For example, suitable values may be programmed in various ways, such as transmission via wireless or wired means, or entry by a user or operator. Responsive to those values, the DMDs and SLMs effectuate the desired intensity modulation and polarization changes to produce an output light with desired spectral and polarization characteristics. In some implementations, the values may be stored in a storage device or a memory (e.g., in the form of a lookup table, in a database, etc.), which can subsequently be retrieved and used by DMDs and SLMs. Additionally, or alternatively, in some implementations, the proper values may be computed using a processor based on functional relationships and then provided to the DMDs and SLMs. The values are changeable or reprogrammable, which enables customization of spectral and polarization characteristics of light that is output from the adjustable light source apparatus.

[0037] In some applications such as telecommunication, the input light to the light source apparatus can be multiple arrays of lasers that are delivered via multiple channels (e.g., fibers) with differing polarization and spectral characteristics, for example covering the standard telecommunication ITU grid. In this scenario, the light source apparatus can be configured to produce output light with uniform spectral and polarization characteristics for all channels, thus eliminating or reducing the variability that would be otherwise present in the light from multiple channels. In other scenarios, the light source apparatus can also be configured to optimize the information transmission through an optical fiber network.

[0038] In some embodiments, devices other than a DMD can be used to modulate the intensity of the spectrally separated wavelength components. For example, in some implementations a pixelated SLM can be used to modify the intensity of the spectrally separated wavelength components responsive to a set of values (voltage values) applied the one or more pixels of the SLM. Any additional polarization aberrations that are introduced by the SLM can be corrected, if needed, by including additional polarization control elements, and/or compensated during the calibration process as discussed above.

[0039] One aspect of the disclosed embodiments relates to an adjustable light source apparatus that includes a dispersive element positioned to receive input light and to produce light having a plurality of spatially separated wavelength components, a digital micromirror device (DMD) including a plurality of micromirrors that are configured to operate in response to a first set of values, the DMD positioned to receive the plurality of the spatially separated wavelength components and to modulate intensity of the plurality of the spatially separated wavelength components based on the first set of values. The adjustable light source also includes a polarizer positioned to receive light that is output from the DMD, and at least one pixelated spatial light modulator (SLM) configured to operate in response to at least a second set of values. The at least one pixelated SLM is positioned to receive polarized light from the polarizer and to impart a polarization change to the polarized light based on the second set of values. The DMD is configured to impart a particular spectral shape to the spectrally separated wavelength components based on the first set of values, the at least one pixelated SLM is operable, on a pixel-by-pixel basis, to move a polarization state of the polarized light incident on each pixel to another polarization state, and the first set of values and the second set of values are adjustable to enable customization of spectral and polarization characteristics of light that is output from the adjustable light source apparatus.

[0040] In one example embodiment, the dispersive element is a first dispersive element, and the adjustable light source apparatus further includes a second dispersive element positioned to receive light that is output from the at least one SLM, and to spatially combine the spatially separated wavelength components. In another example embodiment, the adjustable light source apparatus includes a collimating lens positioned to receive the input light prior to reaching the dispersive element (the first dispersive element), and to produce collimated light directed to the dispersive element (the first dispersive element). In yet another example embodiment, the adjustable light source includes a focusing lens configured to receive light that is output from the at least one SLM or from the second dispersive element and to produce focused light at a focal plane thereof.

[0041] According to another example embodiment, the at least one pixelated SLM includes a first and a second pixelated SLMs positioned in a series configuration and with pixels of the first SLM being in alignment with pixels of the second SLM, the second set of values includes a first subset of values associated with the first pixelated SLM and a second subset of values associated with the second pixelated SLM, the first pixelated SLM is responsive to the first subset of values to modify a polarization state of light that is incident on the first pixelated SLM to an interim polarization state, and the second pixelated SLM is responsive to the second subset of values to modify the interim polarization state to a final polarization state. In one example embodiment, the adjustable light source apparatus includes a relay optics positioned between the first and the second pixelated SLMs.

[0042] In another example embodiment, the at least one pixelated SLM consists of one pixelated SLM including two sections, wherein a first section of the pixelated SLM is positioned to receive the polarized light and a second section of the pixelated SLM is positioned to receive light from the first section of the pixelated SLM. In this configuration, the second set of values includes a first subset of values associated with the first section of the pixelated SLM and a second subset of values associated with the second section of the pixelated SLM, the first section of the pixelated SLM is responsive to the first subset of values to modify a polarization state of light that is incident on the first section of the pixelated SLM to an interim polarization state, and the second section of the pixelated SLM is responsive to the second subset of values to modify the interim polarization state to a final polarization state.

[0043] In yet another example embodiment, one or both of the first or the second dispersive elements are: (a) operable in transmission, or (b) operable in reflection. In another example embodiment, the at least one pixelated SLM is operable in (a) transmission or (b) reflection. In still another example embodiment, the adjustable light source apparatus includes an input light source, for example, the input light source is one, or a combination, of: a xenon lamp, a laser, a supercontinuum light source, an optical frequency comb, or a light emitting diode (LED) array. In another example embodiment, the input light has a spectral bandwidth in one or more of the following ranges: 380 nm to 750 nm, 750 nm to 1 micron, or 1 micron to 2.5 micron.

[0044] In one example embodiment, the adjustable light source apparatus is configured to produce the light that is output therefrom having at least four wavelength components, wherein each of the wavelength components has a different polarization state compared to each of the other wavelength components. In another example embodiment, the polarization state of the light that is output from the adjustable light source apparatus includes linear, circular and elliptical polarization states. In still another example embodiment, the polarizer is a linear polarizer. In yet another example embodiment, the adjustable light source apparatus includes an achromatic wave plate that is positioned in an optical path between the first and the second dispersive elements to reduce polarization dependent loss (PDL).

[0045] According to another example embodiment, the dispersive element, the DMD, the polarizer and the at least one pixelated SLM are configured as a first section of the adjustable light source apparatus that is positioned to receive the input light that is in a first range of spectral values, the adjustable light source apparatus further includes an additional dispersive element, and additional DMD, an additional polarizer and at least one additional pixelated SLM that are positioned in a second section of the adjustable light source apparatus. In this configuration, the additional dispersive element is positioned to receive the input light that is in a second range of spectral values different than the first range of spectral values, and the additional DMD and the at least one additional pixelated SLM are configured, respectively, to receive an additional first set of values and an additional second set of values to enable customization of the spectral and polarization characteristics of light that is output from the adjustable light source apparatus in the second range of spectral values. In another example embodiment, the first range of spectral values is in a visible range of spectrum, and the second range of spectral values in is an infrared range of spectrum.

[0046] Another aspect of the disclosed embodiments relates to a programmable light source apparatus that includes a dispersive element positioned to receive input light and to produce light having a plurality of spatially separated wavelength components, a polarizer, at least one pixelated spatial light modulator (SLM) configured to operate in response to a first set of programmable values, and a pixelated intensity modulator configured to operate in response to second set of programmable values. In this configuration, the at least one pixelated SLM is operable, on a pixel-by-pixel basis, to move a polarization state of polarized light incident on each pixel to another polarization state based on a corresponding value of the first set of programmable values; the pixelated intensity modulator is configured to modulate an intensity of the spectrally separated wavelength components based on a corresponding value received by each pixel thereof, and the first set of programmable values and the second set of programmable values can be reprogrammed to enable customization of spectral and polarization characteristics of light that is output from the adjustable light source apparatus.

[0047] In one example embodiment, the pixelated intensity modulator is a digital micromirror device (DMD) that includes a plurality of micromirrors. In another example embodiment, the pixelated intensity modulator is a spatial light modulator (SLM). In yet another example configuration, the pixelated intensity modulator is positioned to receive the plurality of spatially separated wavelength components from the dispersive element, the polarizer is positioned to received light from the pixelated intensity modulator, and the at least one pixelated SLM is positioned to receive the polarized light that is output from the polarizer.

[0048] According to another example embodiment, the polarizer is positioned to receive the plurality of spatially separated wavelength components from the dispersive element, the at least one pixelated SLM is positioned to receive the polarized light that is output from the polarizer, and the pixelated intensity modulator is positioned to received light that is output from the at least one pixelated SLM. In yet another example embodiment, the first set of values correspond to a first set of voltage values, and the second set of values correspond to a second set of voltage values.

[0049] It is understood that the various disclosed embodiments may be implemented individually, or collectively, using devices comprised of various optical components, electronics hardware and/or software modules and components. These devices, for example, may comprise a processor, a memory unit, an interface that are communicatively connected to each other, and may range from desktop and/or laptop computers, to mobile devices and the like. The processor and/or controller can perform various disclosed operations based on execution of program code that is stored on a storage medium. The processor and/or controller can, for example, be in communication with at least one memory and with at least one communication unit that enables the exchange of data and information, directly or indirectly, through the communication link with other entities, devices and networks. The communication unit may provide wired and/or wireless communication capabilities in accordance with one or more communication protocols, and therefore it may comprise the proper transmitter/receiver antennas, circuitry and ports, as well as the encoding/decoding capabilities that may be necessary for proper transmission and/or reception of data and other information. For example, the processor may be configured to determine the voltage, current or other signal values for controlling the operations of spatial light modulators and digital microdevices based on the techniques disclosed herein.

[0050] Various information and data processing operations described herein may be implemented in one embodiment by a computer program product, embodied in a computer-readable medium, including computer-executable instructions, such as program code, executed by computers in networked environments. A computer- readable medium may include removable and non-removable storage devices including, but not limited to, Read Only Memory (ROM), Random Access Memory (RAM), compact discs (CDs), digital versatile discs (DVD), etc. Therefore, the computer-readable media that is described in the present application comprises non- transitory storage media. Generally, program modules may include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes.

[0051] The foregoing description of embodiments has been presented for purposes of illustration and description. The foregoing description is not intended to be exhaustive or to limit embodiments of the present invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments. The embodiments discussed herein were chosen and described in order to explain the principles and the nature of various embodiments and its practical application to enable one skilled in the art to utilize the present invention in various embodiments and with various modifications as are suited to the particular use contemplated. While operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. The features of the embodiments described herein may be combined in all possible combinations of methods, apparatus, modules, and systems.