DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 7/27/2026 has been entered.
Response to Arguments
Claim Objections
The objections to the claims are overcome by amendment.
Prior Art Rejections
Applicant’s first argument is that Wang does not teach a non-magnetic dispersive polarization-rotating crystal. Applicant’s second argument is that Klipov does not teach a tunable hyperspectral-polarimetric imaging system in which to place a non-magnetic dispersive polarization-rotating crystal. Both of these arguments are unpersuasive, as one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
Applicant’s third argument is that the previous action did not adequately explain why one of ordinary skill in the art would have expected the proposed combination to preserve Wang’s wavelength-selective spectral imaging functionality with a reasonable expectation of success. This argument is not persuasive. The previous action points out that Klipov teaches the use of quartz for use in optical rotators, further citing Chandrasekhar as a teaching reference to show that the optical rotation of quartz is dispersive, which fulfils the function performed by the magneto-optic materials taught explicitly by Wang. Further, it may be noted that the field of optical measuring and testing, to which the claimed invention belongs, is a relatively predictable field with a relatively high level of knowledge expected of one of ordinary skill. As a result, one of ordinary skill in the art could reasonably predict the effects of such a substitution. Nevertheless, a more detailed explanation is offered herein.
Wang teaches a device that uses dispersive polarization rotation to produce wavelength dependent spectral filtering. The mechanism of action is most concisely explained in FIG. 2 with later embodiments refining the principle in several ways, which shows a beam of light entering the system from the left-hand side of the figure. A variety of wavelengths (shown as three wavelengths in FIG. 2) are present in the beam as it enters, each in an unpolarized state. The first polarizing filter, labeled P0, causes light of all the wavelengths to be polarized along a single axis. A dispersive optical rotator is used to rotate the polarization directions of the different wavelengths of light by different amounts. As a result, light of the first wavelength is at a 45° angle to the second polarizer and is attenuated. Light of the second wavelength is aligned with the second polarizer and is allowed through unimpeded. Light of the third wavelength is orthogonal to the second polarizer and is essentially blocked. With this understanding of the mechanism of action of Wang, a different type of wavelength-dispersive polarization rotator that produces the same set of polarization directions for each wavelength would produce the same overall output attenuating, passing, and blocking those three wavelengths in the same manner. Klipov teaches an alternative type of polarization rotator, which Chandrasekhar demonstrates to be wavelength dispersive. If one wishes to tune the wavelengths that are attenuated, passed, and blocked, Wang teaches several ways of doing so, including an embodiment shown in FIG. 19, which relies on rotating the polarizing filters, not relying on an ability to tune the total extent of optical rotation after the device is constructed, as well as an embodiment in FIG. 27 that includes controlling actuators on each of the polarizers to control their orientations individually.
Applicant’s fourth argument is that Wang’s element operates through Faraday rotation and magnetic-field-dependent tuning, failing to teach the claimed a mechanism interchangeable for the claimed tuning method; however, this argument is not persuasive. While Wang does choose Faraday rotation as a means of rotating polarization states of light, Wang also teaches embodiments in which the tuning is or can be performed by rotating polarizing filters (FIG. 19 and FIG. 27), which does not rely on magnetic-field-dependent tuning. As a result, the embodiment of FIG. 19 is compatible with other materials that perform dispersive optical rotation even if the strength of the dispersive optical rotation is not tunable, since the tuning is performed by rotating the polarizers, and the embodiment of FIG. 27 is compatible with a polarizer-rotating approach as well.
In response to Applicant's fifth argument, that the examiner's conclusion of obviousness is based upon improper hindsight reasoning, it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971).
Applicant’s similar arguments regarding independent claims 15 and 19 are unpersuasive for similar reasons.
Since the independent claims are not allowed, the dependent claims are not automatically allowable.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claim(s) 1-10 and 12-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang (US Patent Publication 20200192133) in view of Klipov (Non-Patent Literature “Large Quartz Crystals for High Power Optical and Laser Applications”).
Regarding claim 1, Wang teaches a tunable hyperspectral-polarimetric imaging system, comprising:
a first polarizer (FIG. 2, polarizer P0) configured to transmit an electromagnetic radiation wave of first polarization in a first direction of polarization (FIG. 2, polarization state oriented vertically on the page), wherein the electromagnetic radiation wave of first polarization includes all wavelengths in a spectral range (FIG. 2, all three initial wavelengths are included in the polarized light downstream of polarizer P0);
a crystal filter (FIG. 2, dispersive magneto-optic material MO) in communication with the first polarizer to receive the electromagnetic radiation wave of first polarization (FIG. 2, note that the light coming from polarizer P0 is polarized vertically on the page), wherein the electromagnetic radiation wave of first polarization includes a plurality of different wavelengths within the spectral range (FIG. 2, wavelengths λ1, λ2, and λ3), and wherein the crystal filter is configured to dispersively rotate the first direction of polarization for the electromagnetic radiation wave of first polarization by different rotation angles for the different wavelengths in the spectral range to generate different directions of polarization for the different wavelengths (FIG. 2, each wavelength has a different polarization orientation downstream of dispersive magneto-optic material MO);
a second polarizer (FIG. 2, polarizer P1) in communication with the crystal filter, wherein the second polarizer is configured to transmit an electromagnetic radiation wave of second polarization in a second direction of polarization selected from the different directions of polarization generated by the crystal filter to generate a transmission spectrum of the imaging system (FIG. 2, light exiting polarizer P1, which transmits the light of wavelength λ2, but not the light of wavelength λ3. Note that the direction of polarization transmitted can be tuned by rotating the second polarizer, as shown in FIG. 19 and FIG. 27); and
a sensor configured to sense and output a signal indicative of a spectral image (FIG. 1, focal plane array 18) at a predetermined wavelength corresponding to the electromagnetic radiation wave of second polarization (FIG. 2, λ2).
Wang uses a magneto-optic material to achieve the dispersive optical rotation, so does not rotate the polarization of light without application of a magnetic field.
In the same field of endeavor of optical rotation, Klipov does teach a way to rotate the polarization of light without application of a magnetic field (second page, third full paragraph, which describes how the screw component in the crystal structure of quartz explains its optical activity (rotation) in a particular direction. Note that the screw component and the associated optical rotation are present even without applying a magnetic field. Note that the optical rotation of quartz is dispersive based on wavelength (see the first paragraph of page 483 of Chandrasekhar (Non-Patent Literature “Theoretical Interpretation of the Optical Activity of Quartz”))). By using quartz, Klipov is able to observe optical rotation without needing to apply a magnetic field.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the tunable hyperspectral-polarimetric imaging system of Wang with the quartz crystals of Klipov in order to produce optical rotation without needing the complication of applying a magnetic field achieving the same predictable result of filtering light in a way that can be tuned by the angle of one or more polarizers (see paragraph 20 of Wang). Since quartz was used in optical rotators (Klipov, page 2, third full paragraph) and was known to be wavelength-dispersive in its optical activity (as described by Chandrasekhar), one of ordinary skill in the art would have had a reasonable expectation of success in accomplishing the wavelength-dispersive optical rotation shown in FIG. 2 of Wang even when replacing the magneto-optic material with quartz without applying a magnetic field, thereby achieving wavelength-selective filtering with the two polarizers.
Regarding claim 2, Wang, as modified by Klipov, teaches or renders obvious the tunable hyperspectral-polarimetric imaging system of claim 1 (as described above).
Wang further teaches controller circuitry configured (FIG. 27, master controller 40) to rotate the second polarizer to change the electromagnetic radiation wave of second polarization to another second direction of polarization to tune the electromagnetic radiation wave of second polarization (FIG. 27, actuator A1).
Regarding claim 3, Wang, as modified by Klipov, teaches or renders obvious the tunable hyperspectral-polarimetric imaging system of claim 1 (as described above).
Wang does not explicitly teach that the crystal filter comprises at least one of quartz, Te, Se, TeO2, AgGaS2, Benzil, LiIO3, HIO3, Bi12GeO20, HgS, Hg3Te2Cl2, GaSe, or (GaxIn1-x)2Se3.
In the same field of endeavor of optical rotation, Klipov does teach that the crystal filter comprises at least one of quartz, Te, Se, TeO2, AgGaS2, Benzil, LiIO3, HIO3, Bi12GeO20, HgS, Hg3Te2Cl2, GaSe, or (GaxIn1-x)2Se3 (quartz, described on the second page, third full paragraph, and elsewhere as having optical rotation). By using quartz, Klipov is able to observe optical rotation without needing to apply a magnetic field.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the tunable hyperspectral-polarimetric imaging system of Wang, as modified by Klipov, by using the quartz crystal of Klipov as the specific means to produce the magnetic field-free way of rotating light, with predictable results and a reasonable expectation of success.
Regarding claim 4, Wang, as modified by Klipov, teaches or renders obvious the tunable hyperspectral-polarimetric imaging system of claim 1 (as described above).
Wang does not explicitly teach that the crystal filter is a crystal in a crystal class, the crystal class comprising class 1, class 2, class 222, class 4, class 422, class 3, class 32, class 6, class 622, class 432, class 23, class m, class mm2, class
4
-
or class
4
-
2m.
In the same field of endeavor of optical rotation, Klipov does teach that the crystal filter is a crystal in a crystal class, the crystal class comprising class 1, class 2, class 222, class 4, class 422, class 3, class 32 (second page, second full paragraph, points out that quartz crystal has point symmetry group 32), class 6, class 622, class 432, class 23, class m, class mm2, class
4
-
or class
4
-
2m. By using quartz, which belongs to one of the claimed crystal classes, Klipov is able to observe optical rotation without needing to apply a magnetic field (see second page, second paragraph).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the tunable hyperspectral-polarimetric imaging system of Wang, as modified by Klipov, by using the quartz crystal of Klipov, which belongs to one of the claimed crystal classes, as the specific means to produce the magnetic field-free way of rotating light, with predictable results and a reasonable expectation of success.
Regarding claim 5, Wang, as modified by Klipov, teaches or renders obvious the tunable hyperspectral-polarimetric imaging system of claim 1 (as described above).
Wang further teaches that the crystal filter is substantially transparent (FIG. 2, note that the electromagnetic waves that enter dispersive magneto-optic material MO also exit it) and has dispersive optical-activity (DOA) at the spectral range (FIG. 2, different wavelengths of light are dispersed in terms of polarization direction). Note that the quartz of Klipov also exhibits these properties (see the first paragraph of section 1 of Klipov) and that it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have used a kind of quartz with these properties as the quartz used in the tunable hyperspectral-polarimetric imaging system of Wang, as modified by Klipov. Also see the first paragraph of page 483 of Chandrasekhar (Non-Patent Literature “Theoretical Interpretation of the Optical Activity of Quartz”), which points out the rotary dispersion of quartz.
Regarding claim 6, Wang, as modified by Klipov, teaches or renders obvious the tunable hyperspectral-polarimetric imaging system of claim 1 (as described above).
Wang further teaches controller circuitry (FIG. 27, master controller 40) configured to independently rotate the first polarizer (FIG. 27, using actuator A0) and the second polarizer (FIG. 27, using actuator A1), the first polarizer rotated by the controller circuitry to change the electromagnetic radiation wave of first polarization to another first direction of polarization, and the second polarizer rotated by the controller circuitry to change the electromagnetic radiation wave of second polarization to another second direction of polarization to tune the electromagnetic radiation wave of first polarization and the electromagnetic radiation wave of second polarization (paragraph 130. Also see FIG. 2, which shows the electromagnetic waves in ways that may be instructive in interpreting FIG. 27).
Regarding claim 7, Wang, as modified by Klipov, teaches or renders obvious the (as described above).
Wang further teaches the controller circuitry is configured to initially rotate the first polarizer and the second polarizer to a predetermined same direction of polarization to align the first polarizer and the second polarizer (FIG. 6 shows a case, case 1, in which polarizer P0 and polarizer P1 are aligned vertically along the page), before independent rotation of the first polarizer and the second polarizer to tune the electromagnetic radiation wave of first polarization and the electromagnetic radiation wave of second polarization (FIG. 27, using separate actuators, A0 and A1).
Regarding claim 8, Wang, as modified by Klipov, teaches or renders obvious the tunable hyperspectral-polarimetric imaging system of claim 1 (as described above).
Wang further teaches a motor configured to physically rotate at least one of the first polarizer (FIG. 27, actuator A0), the second polarizer (FIG. 27, actuator A1), or the crystal filter.
Regarding claim 9, Wang, as modified by Klipov, teaches or renders obvious the tunable hyperspectral-polarimetric imaging system of claim 1 (as described above).
Wang further teaches a controller circuitry (FIG. 27, master controller 40) configured to rotate the first polarizer (FIG. 27, actuator A0), the second polarizer (FIG. 27, actuator A1), or both, wherein the first polarizer, or the second polarizer, or both comprise an electro-optically tunable polarizer tunably controlled by control signals from the controller circuitry (FIG. 27, master controller 40 uses electrical signals to tune the optical properties of the polarizers, specifically the direction of polarization).
Regarding claim 10, Wang, as modified by Klipov, teaches or renders obvious the tunable hyperspectral-polarimetric imaging system of claim 1 (as described above).
Wang further teaches that the spectral range of the electromagnetic radiation wave is in a range of wavelengths from 400nm to 750nm (FIG. 1A, visible image sensor 1A. Note that wavelengths of 400 nm to 750 nm roughly correspond to the portion of the electromagnetic spectrum considered to be visible light.).
Wang does not explicitly teach that the crystal filter comprises a quartz single crystal cut along a (0001) surface.
In the same field of endeavor of optical rotation, Klipov does teach a quartz single crystal cut along a (0001) surface (second page, second and third full paragraphs). Klipov points out that (0001) cut quartz is often used for optical rotation.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the tunable hyperspectral-polarimetric imaging system of Wang, as modified by Klipov, with the (0001) cut quartz of Klipov as a means to perform the optical rotation of the polarization state of the light studied by Wang, due to the well-known suitability of such quartz for the purpose of optical rotation.
Regarding claim 12, Wang, as modified by Klipov, teaches or renders obvious the tunable hyperspectral-polarimetric imaging system of claim 1 (as described above).
Wang further teaches that the first polarizer and the second polarizer are linear polarizers (FIG. 2, the polarization states downstream of polarizer P0 are shown as linear polarization states, indicating that P0 is a linear polarizer. Polarizer P1 is shown as taking in one linear polarization state and transmitting it (associated with wavelength λ2), while the orthogonal polarization state (associated with wavelength λ3) is blocked. One of ordinary skill in the art would understand from this that polarizer P1 is a linear polarizer. Additionally, a component described as a “polarizer” (as Wang uses), absent any evidence to the contrary, would have been understood by one of ordinary skill in the art to refer to a linear polarizer. Wang lacks such contrary evidence.).
Regarding claim 13, Wang, as modified by Klipov, teaches or renders obvious the tunable hyperspectral-polarimetric imaging system of claim 1 (as described above).
Wang further teaches that the crystal filter comprises a plurality of crystal filters and the second polarizer comprises a plurality of second polarizers (FIG. 27), and wherein a first one of the crystal filters (FIG. 27, MO1) and a first one of the second polarizers (FIG. 27, polarizer P1) are optically aligned to form a first group, and a second one of the crystal filters (FIG. 27, MO2) and a second one of the second polarizers (FIG. 27, P2) are optically aligned to form a second group, the first group optically and sequentially aligned with the first polarizer (FIG. 27, P0) such that the first one of the crystal filters is in optical communication with the first polarizer, and the first one of the second polarizers is optically aligned to optically communicate with the second one of the crystal filters (FIG. 27, optical communication occurs along optical axis 16).
Regarding claim 14, Wang, as modified by Klipov, teaches or renders obvious the tunable hyperspectral-polarimetric imaging system of claim 13 (as described above).
Wang further teaches that the crystal filters comprise right-handed crystals having a clockwise rotational direction of polarization for the electromagnetic radiation wave and left-handed crystals having a counter-clockwise rotational direction of polarization for the electromagnetic radiation wave (FIG. 26. While not explicit which set of crystal filters has clockwise and which has counter-clockwise rotation, the dispersive element in device 210 has a rotation direction opposite those in filter 200, so both rotation directions are represented).
Note that the quartz crystals used by Klipov also have left and right handed forms with opposite directions of rotation (see the first paragraph of page 483 of Chandrasekhar (Non-Patent Literature “Theoretical Interpretation of the Optical Activity of Quartz”), which points out that the two enantiomers of quartz have opposite rotation directions) and that it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have designed the tunable hyperspectral-polarimetric imaging system of Wang, as modified by Klipov, to use the two enantiomers of quartz to provide the two rotation directions, with predictable results and a reasonable expectation of success.
Regarding claim 15, Wang teaches a method of image analysis comprising:
transmitting electromagnetic radiation through a first polarizer (FIG. 2, polarizer P0);
generating, with the first polarizer, an electromagnetic radiation wave of first polarization in a first direction of polarization (FIG. 2, polarization state oriented vertically on the page), wherein the electromagnetic radiation wave of first polarization includes all wavelengths in a spectral range (FIG. 2, all three initial wavelengths are included in the polarized light downstream of polarizer P0);
receiving, with a crystal filter in communication with the first polarizer, the electromagnetic radiation wave of first polarization, wherein the crystal filter has dispersive optical activity at the spectral range (FIG. 2, dispersive magneto-optic material MO);
dispersively rotating, with the crystal filter, the first direction of polarization for the electromagnetic radiation wave of first polarization by different rotation angles for different wavelengths in the spectral range (FIG. 2, each wavelength has a different polarization orientation downstream of dispersive magneto-optic material MO);
receiving, with a second polarizer in communication with the crystal filter, the plurality of different wavelengths (FIG. 2, polarizer P1);
transmitting, with the second polarizer, an electromagnetic radiation wave of second polarization in a second direction of polarization selected from the different directions of polarization generated by the crystal filter (FIG. 2, light exiting polarizer P1, which transmits the light of wavelength λ2, but not the light of wavelength λ3. Note that the direction of polarization transmitted can be tuned by rotating the second polarizer, as shown in FIG. 19 and FIG. 27);
sensing, with a sensor, the electromagnetic radiation wave of second polarization (FIG. 1, focal plane array 18); and
outputting, with the sensor, a signal representative of a spectral image at a predetermined wavelength corresponding to the electromagnetic radiation wave of second polarization (FIG. 2, λ2).
Wang uses a magneto-optic material to achieve the dispersive optical rotation, so does not rotate the polarization of light without application of a magnetic field.
In the same field of endeavor of optical rotation, Klipov does teach a way to rotate the polarization of light without application of a magnetic field (second page, third full paragraph, which describes how the screw component in the crystal structure of quartz explains its optical activity (rotation) in a particular direction. Note that the screw component and the associated optical rotation are present even without applying a magnetic field. Note that the optical rotation of quartz is dispersive based on wavelength (see the first paragraph of page 483 of Chandrasekhar (Non-Patent Literature “Theoretical Interpretation of the Optical Activity of Quartz”))). By using quartz, Klipov is able to observe optical rotation without needing to apply a magnetic field.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of image analysis of Wang with the quartz crystals of Klipov in order to produce optical rotation without needing the complication of applying a magnetic field achieving the same predictable result of filtering light in a way that can be tuned by the angle of one or more polarizers (see paragraph 20 of Wang). Since quartz was used in optical rotators (Klipov, page 2, third full paragraph) and was known to be wavelength-dispersive in its optical activity (as described by Chandrasekhar), one of ordinary skill in the art would have had a reasonable expectation of success in accomplishing the wavelength-dispersive optical rotation shown in FIG. 2 of Wang even when replacing the magneto-optic material with quartz without applying a magnetic field, thereby achieving wavelength-selective filtering with the two polarizers.
Regarding claim 16, Wang, as modified by Klipov, teaches or renders obvious the method of claim 15 (as described above).
Wang further teaches controlling, with a controller circuitry (FIG. 27, master controller 40), rotation of the first polarizer to change the electromagnetic radiation wave of first polarization to another first direction of polarization (FIG. 27, using actuator A0), and controlling, with the controller circuitry, rotation of the second polarizer to change the electromagnetic radiation wave of second polarization to another second direction of polarization (FIG. 27, using actuator A1) to tune the electromagnetic radiation wave of first polarization and the electromagnetic radiation wave of second polarization (paragraph 130. Also see FIG. 2, which shows the electromagnetic waves in ways that may be instructive in interpreting FIG. 27).
Regarding claim 17, Wang, as modified by Klipov, teaches or renders obvious the method of claim 15 (as described above).
Wang further teaches controlling, with a controller circuitry (FIG. 27, master controller 40), rotation of the second polarizer to change the electromagnetic radiation wave of second polarization to another second direction of polarization to tune the electromagnetic radiation wave of second polarization (FIG. 27, actuator A1).
Regarding claim 18, Wang, as modified by Klipov, teaches or renders obvious the method of claim 15 (as described above).
Wang further teaches sequentially rotating the second polarizer to a plurality of different rotatable orientations to change the electromagnetic radiation wave of second polarization to multiple different corresponding second directions of polarization to tune the electromagnetic radiation wave of second polarization (shown in FIG. 19, but used elsewhere, too, including FIG. 27).
Regarding claim 19, Wang teaches a tunable hyperspectral-polarimetric imaging system, comprising:
a first polarizer (FIG. 2, polarizer P0) configured to generate from electromagnetic radiation a polarized electromagnetic radiation of one direction (FIG. 2, polarization state oriented vertically on the page) comprising a plurality of wavelengths (FIG. 2, all three initial wavelengths are included in the polarized light downstream of polarizer P0);
a crystal filter (FIG. 2, dispersive magneto-optic material MO) in optical axial alignment with the first polarizer, the crystal filter configured to receive the polarized electromagnetic radiation of one direction, wherein the crystal filter has dispersive optical activity at the spectral range and is configured to dispersively rotate the direction of polarization with different rotation angles for different wavelengths to generate different directions of polarization for the different wavelengths (FIG. 2, each wavelength has a different polarization orientation downstream of dispersive magneto-optic material MO);
a second polarizer (FIG. 2, polarizer P1) in optical axial alignment with the crystal filter, the second polarizer configured as a tunable spectral filter to generate a transmission spectrum at each of a plurality of different polarization directions corresponding to the different directions of polarization generated by the crystal filter according to an axial orientation of the second polarizer according to an axial orientation of the second polarizer with respect to an optical axis of the second polarizer (FIG. 2, light exiting polarizer P1, which transmits the light of wavelength λ2, but not the light of wavelength λ3. Note that the direction of polarization transmitted can be tuned by rotating the second polarizer, as shown in FIG. 19 and FIG. 27); and
a sensor configured to generate a spectral frame (FIG. 1, focal plane array 18) for the transmission spectrum at each of the plurality of different polarization directions, the spectral frame representative of a spectral image at a respective polarization direction (FIG. 2, λ2).
Wang uses a magneto-optic material to achieve the dispersive optical rotation, so does not rotate the polarization of light without application of a magnetic field.
In the same field of endeavor of optical rotation, Klipov does teach a way to rotate the polarization of light without application of a magnetic field (second page, third full paragraph, which describes how the screw component in the crystal structure of quartz explains its optical activity (rotation) in a particular direction. Note that the screw component and the associated optical rotation are present even without applying a magnetic field. Note that the optical rotation of quartz is dispersive based on wavelength (see the first paragraph of page 483 of Chandrasekhar (Non-Patent Literature “Theoretical Interpretation of the Optical Activity of Quartz”))). By using quartz, Klipov is able to observe optical rotation without needing to apply a magnetic field.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the tunable hyperspectral-polarimetric imaging system of Wang with the quartz crystals of Klipov in order to produce optical rotation without needing the complication of applying a magnetic field achieving the same predictable result of filtering light in a way that can be tuned by the angle of one or more polarizers (see paragraph 20 of Wang). Since quartz was used in optical rotators (Klipov, page 2, third full paragraph) and was known to be wavelength-dispersive in its optical activity (as described by Chandrasekhar), one of ordinary skill in the art would have had a reasonable expectation of success in accomplishing the wavelength-dispersive optical rotation shown in FIG. 2 of Wang even when replacing the magneto-optic material with quartz without applying a magnetic field, thereby achieving wavelength-selective filtering with the two polarizers.
Regarding claim 20, Wang, as modified by Klipov, teaches or renders obvious the tunable hyperspectral-polarimetric imaging system of claim 19 (as described above).
Wang further teaches a controller circuitry configured to axially rotate the second polarizer to each of the different polarization directions (FIG. 27, master controller 40, connected to actuator A1).
Claim(s) 11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang (US Patent Publication 20200192133) in view of Klipov (Non-Patent Literature “Large Quartz Crystals for High Power Optical and Laser Applications”) and Ades (Non-Patent Literature “Optical activity of tellurium to 20 µm”).
Regarding claim 11, Wang, as modified by Klipov, teaches or renders obvious the tunable hyperspectral-polarimetric imaging system of claim 1 (as described above).
While Wang generally teaches the use of a broader spectral range (see FIG. 7, FIG. 8, etc., which plot a spectral range from 2 or 3 µm to 14 µm), a spectral range of the electromagnetic radiation wave in a range of wavelengths from 3.8 µm to 6 µm is encompassed by the range disclosed by Wang.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have studied the particular subrange of 3.8 µm to 6 µm out of the broader range studied by Wang in order to measure particular optical phenomena associated with that particular subrange of wavelengths.
Wang does not explicitly teach that the crystal filter comprises a tellurium (Te) single crystal cut along a (0001) surface.
In the same field of endeavor of rotating the polarization of light, Ades teaches that the crystal filter comprises a tellurium (Te) single crystal cut along a (0001) surface (paragraph 1). Ades shows that tellurium cut along that particular plane can be used for left- and right-handed optical rotations in the wavelength range claimed (FIG. 1).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the tunable hyperspectral-polarimetric imaging system of Wang, as modified by Klipov, with the (0001) cut tellurium of Ades as an alternative to the quartz of Klipov in order to take advantage of the dispersive levorotatory and/or dextrorotatory effects of tellurium in the desired wavelength range, still without applying a magnetic field.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to PAUL D SCHNASE whose telephone number is (703)756-1691. The examiner can normally be reached Monday - Friday 8:30 AM - 5:00 PM ET.
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/PAUL SCHNASE/Examiner, Art Unit 2877
/TARIFUR R CHOWDHURY/Supervisory Patent Examiner, Art Unit 2877
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