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 .
Acknowledgement made of amendment filed 3/27/2026.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
Claim(s) 1-4, 9, 11-12 14 and 16-18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Edwards et al. (US 6,041,610) in view of Hehlen et al. (First demonstration of an all-solid-state optical cryocooler), copy of NPL provided by applicant.
Regarding claim 1, Edwards teaches a multi-pass optical cavity (10, Disk of cooling material, figure 1);
A first mirrored glass (column 6 lines 34-35);
A first mirror (14, Tuned dielectric mirror, figure 1) comprising a hole (26, figure 1) that allows a pump laser (24, figure 1) beam to enter, wherein the first mirror is positioned at a first end of the first mirrored glass (see lower side of 10, figure 1),
A second mirror (12, Broadband dielectric mirror, figure 1), and
A laser source (24, figure 1) that produces a divergent laser beam or that produces a laser beam that is made divergent using one or more optical elements that is coupled into the first mirrored glass (see 22 is made divergent by something upon entering 26 as shown in figure 1),
Wherein the laser beam is reflected within the first mirrored glass between the first mirror and the second mirror by total internal reflection (column 5 lines 39-43), and
the first mirror has a low reflectivity for longer wavelengths of a fluorescence spectrum (column 5 lines 1-8).
Edwards does not teach the working material is a crystal.
Hehlen teaches the working material is a crystal of YB doped YLF material (see abstract) and making the laser beam divergent using a lens (Focusing lens, figure 1).
It would have been obvious to a person having ordinary skill in the art at the time the invention was made to modify solid state cryocooler of Edwards to use a crystal such as taught in Hehlen in order to improve cooling efficiency over Yb doped ZBLAN (see Introduction, page 1 left column).
Regarding claim 2, Edwards teaches the first mirror comprises a spectrally selective coating (14, figure 1) to suppress amplified spontaneous emission and parasitic lasing to avoid undesired heat generation in a material being cooled in the multi-pass optical cavity and the spectrally selective coating is deposited on the mirrored Yb doped glass such that a stable laser resonator is not formed (column 5 lines 29-39).
Edwards does not teach the working material is a crystal.
Hehlen teaches the working material is a crystal of YB doped YLF material (see abstract) and making the laser beam divergent using a lens (Focusing lens, figure 1)
It would have been obvious to a person having ordinary skill in the art at the time the invention was made to modify solid state cryocooler of Edwards to use a crystal such as taught in Hehlen in order to improve cooling efficiency over Yb doped ZBLAN (see Introduction, page 1 left column).
Regarding claim 3, Edwards teaches the spectrally selective coating of the first mirror comprises a long pass mirror coating and the spectrally selective coating of the second mirror comprises a short pass mirror coating (column 5 lines 9-20).
Regarding claim 4 and 9, Edwards does not specify one or more optical elements comprise one or more lenses or one or more aberrator plates.
Hehlen teaches an optical element comprises one or more lenses (Focusing lens, figure 1).
It would have been obvious to a person having ordinary skill in the art at the time the invention was made to modify the cryogenic cooler of Edwards to use the lens of Hehlen in order to focus the laser onto a narrower opening in the spectrally selective mirror to improve efficiency.
Regarding claim 11, Edwards does not specify a first mirrored crystal.
Hehlen teaches the working material is a crystal of YB doped YLF material (see abstract).
It would have been obvious to a person having ordinary skill in the art at the time the invention was made to modify solid state cryocooler of Edwards to use a crystal such as taught in Hehlen in order to improve cooling efficiency over Yb doped ZBLAN (see Introduction, page 1 left column).
Regarding claim 12, Edwards teaches the spectrally selective coating introduces a loss at wavelengths longer than a pump laser and prevents buildup of ASE and eliminates laser oscillation at longer wavelengths by ensuring a net optical gain that never exceeds losses in each roundtrip in the multi-pass optical cavity (column 5 lines 29-39).
Regarding claim 14, Edwards teaches the spectrally selective coating comprises a dielectric coating (Tuned dielectric mirror, figure 1).
Regarding claim 16-18, Edwards teaches directing a divergent laser beam (see 24, 22, going through opening 26, wherein laser input is shown to be made divergent after passing through 26, figure 1) into a multi-pass optical cavity (10, figure 1), the multi-pass cavity comprising a first mirror (12, figure 1) positioned at a first end of the multi-pass cavity and a second mirror (14, figure 1) positioned at a second end of the multi-pass optical cavity, wherein the second mirror (tuned dielectric mirror, 14, figure 1) comprises a spectrally selective coating to suppress amplified spontaneous emission and parasitic lasing to avoid undesired heat generation in a material being cooled in the mutli-pass optical cavity (column 5 lines 15-21) and the spectrally selective coating is deposited onto the Yb doped glass such that a stable laser resonator is not formed (column 5 lines 29-39); the first mirror has a low reflectivity for longer wavelengths of a fluorescence spectrum (column 5 lines 1-8) and
Optically cooling the material by repeated passes of the pump laser beam (column 5 lines 29-39).
Edwards does not teach the working material is a crystal.
Hehlen teaches the working material is a crystal of YB doped YLF material (see abstract).
It would have been obvious to a person having ordinary skill in the art at the time the invention was made to modify solid state cryocooler of Edwards to use a crystal such as taught in Hehlen in order to improve cooling efficiency over Yb doped ZBLAN (see Introduction, page 1 left column).
Claim(s) 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Edwards et al. (US 6,041,610) in view of Hehlen et al. (First demonstration of an all-solid-state optical cryocooler), copy provided by Applicant, as applied to claim 1 above and further in view of Rubin (US 2019/0049364 A1).
Regarding claim 15, Edwards in view of Hehlen does not teach an optical fiber that couples the laser source to the first mirrored crystal.
Rubin teaches an optical fiber coupling a laser into a Herriott cell (56, figure 2).
It would have been obvious to a person having ordinary skill in the art at the time the invention was made to modify the cryocooler of Edwards in view of Hehlen to use a fiber laser as taught in Rubin in order to allow more flexible placement of the laser to make the device more compact, while still keeping allow the laser heat source to be placed away from the working material.
Response to Arguments
Applicant's arguments filed 3/27/2026 have been fully considered but they are not persuasive.
Regarding Applicant’s arguments that Edwards teaches the opposite of the claimed ‘first mirror, the second mirror, or both the first mirror and the second mirror have low reflectivity for longer wavelengths of a fluorescence spectrum’ (see arguments page 6, paragraph 1), examiner respectfully notes that the claim does not specify the range of the wavelengths for which reflection is low, therefore, even teaching tuning the mirror for ‘shorter wavelength radiation’ as long as it is fluorescent radiation would be sufficient for the claim, because even the shorter wavelength radiation is longer than other parts of the electromagnetic spectrum. Nevertheless, regarding Applicant’s assertion that Edwards teaches the reflection at the low-energy portion of the fluorescent spectrum is high (>0.999) is incorrect. In column 5 line 6, the reflectivity is greater than or equal to 90% not 99.9%. The 99.9% reflectivity is reserved for pump radiation wavelength. Thus 90% reflectivity of the fluorescent wavelength can be considered low relative to the 99.9% reflectivity for the pump wavelength. In either interpretation, Applicant’s arguments on this point are not persuasive.
Regarding the argument (page 6-7) that the laser beam does not produce a divergent laser beam and that instead the lines represent alternative angles of the input laser beam, examiner notes that there is no teaching in Edwards to support this assertion, This would require a complicated scanning architecture in between he input holes to create the multiple photon paths shown after the input hole 26.. Edwards teaches (column 5 lines 27-31) that the ‘Solid lines, 22, depict pump photons from laser 24. The pump light enters the cooling material 10 through an input hole 26, in mirror 14). These photons are reflected between he mirrors until they are absorbed (denoted by large, black dots, 28).” Figure 1 clearly shows there are multiple photon lines entering the cooling glass between mirror 14 and 12 after going through hole 26), and without the explicit teaching of a complex optical device to change the input angle through the second hole temporally, one of ordinary skill in the art, would opt for the simpler solution of a laser beam made divergent upon entering 26 by some kind of optical element. Nevertheless, the teaching of Edwards was not relied upon alone to teach this feature. Hehlen was used to teach the focusing lens for focusing laser light at the entrance aperture. And if light is made to focus at the aperture by a lens then it necessarily diverges past the aperture without any additional optical elements. (see figure 1 of Hehlen, and Results and Discussion section on page 4, subsection ‘Cooling crystal and Herriott cell’ wherein the laser is explicitly stated as being focused into the cell with a spherical lens through a 400 micrometer diameter center hole in the input mirror, therefore Applicant’s arguments on this point are not persuasive.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to RYAN D HOWARD whose telephone number is (571)270-5358. The examiner can normally be reached M-F 8-5:00.
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/RYAN D HOWARD/Primary Examiner, Art Unit 2882 5/20/2026
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