Non-Final Rejection
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claims 1-20 are pending.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1, 2, 6, 8, and 19 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by US 2006/0227819 (“Irikuchi”).
Regarding claim 1, Irikuchi discloses in Fig. 1 and the discussion thereof esp. [0029] a method for intracavity frequency conversion, comprising steps of: end-pumping (with laser 1) a solid-state gain medium 3 (Nd:YAG) in a laser resonator 7 with a pump laser beam from 1, having a pump power, to generate an intracavity laser beam circulating in the laser resonator;
imposing a loss on the intracavity laser beam (etalon 5 controls the output, compare Figs. 3-5, by imposing a loss via its transmittance);
frequency-converting a portion of the intracavity laser beam in a non-linear crystal 4 located in the laser resonator 7, to generate a frequency-converted laser beam having an output power; and
adjusting the pump power (control circuit 12 via pump drive circuit 9 to keep the power detected at 11 constant, [0030]) and the loss (control circuit 12 via temperature regulator keeps etalon temperature, [0030]; a person skilled in the art understands etalons are highly dependent on temperature. Indeed, if temperature was not important there would be no need for temperature regulator and drive circuit 22/24) to control the output power (again, [0030]) and at least one output beam parameter of the frequency-converted laser beam, the at least one output beam parameter being selected from the group consisting of beam waist size, beam waist location, beam divergence angle, and beam quality factor (by controlling the modes to make the output more like a single mode output, [0040], the etalon controls the beam quality factor).
Regarding claim 2, this is implicitly found in Irikuchi, as the pumping and the lasing will each contribute to thermal lensing in the gain medium, and the contribution from the pump will be higher in the case where a high pump power is used.
Regarding claim 6, Irikuchi is considered to stabilize both the output power and beam parameter as needed. However it is apparent this is only if needed; in the case where the power or beam parameter does not need to be kept stable (because it is already adequately stable) then the adjusting step would leave that unchanged as claimed, while adjusting the other as needed.
Regarding claim 8, Irikuchi monitors the frequency-converted laser beam via 11 to obtain a measure of the output power, the adjusting step including adjusting the pump power and the loss based, at least in part, on the measure of the output power. [0030].
Regarding claim 19, Irikiuchi discloses in Fig. 1 and the discussion thereof esp. [0029] a laser apparatus with intracavity frequency conversion, comprising: a laser resonator 7 including: a solid-state gain medium 3, a nonlinear crystal 4, and an adjustable loss element 5 arranged to impose an adjustable loss on the laser resonator; a pump laser 1 for generating a pump laser beam having a pump power and arranged to end-pump the gain medium so as to generate an intracavity laser beam circulating in the laser resonator and undergoing partial frequency-conversion in the nonlinear crystal to generate a frequency-converted laser beam having an output power; one or more sensors 11 for monitoring the output power and at least one output beam parameter of the frequency-converted laser beam, the at least one output beam parameter being selected from the group consisting of beam waist size, beam waist location, beam divergence angle, and beam quality factor; and a controller configured to control the output power and the at least one output beam parameter by adjusting the pump power and the loss according to monitored values of the output power and the at least one output beam parameter. (See discussion of claim 1 above).
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.
Claims 1-4, 6-8, 10, and 19 are rejected under 35 U.S.C. 103 as being unpatentable over US 2006/0072635 (“Wang”) in view of Irikuchi.
Regarding claim 1, Wang discloses a method for intracavity frequency conversion (Fig. 12, frequency converter 38 is within the resonator, [0060]), comprising steps of:
End pumping (pump system 24,26 is shown as side pumping, but see [0027] disclosing end pumping as being an alternative to the side-pumping shown) a solid state gain medium 23 (Nd:YVO4, [0045]) in a laser resonator (constituted by mirrors 21 and 22, [0026], [0060]) with a pump laser beam, having a pump power, to generate an intracavity laser beam circulating in the laser resonator;
frequency-converting a portion of the intracavity laser beam in a non-linear crystal (frequency converter 38, see e.g. [0034], [0039]) located in the laser resonator, to generate a frequency-converted laser beam having an output power; and
adjusting the pump power (see [0033] pump power is adjusted by controller 50) and the loss (frequency converter is adjusted, see [0033], by e.g. temperature tuning which changes the conversion efficiency and therefore the loss to the fundamental beam, see also temperature adjustment of Irikuchi etalon discussed below) to control the output power ([0033] disclose that thereby the frequency converted power is maintained at a desired value, i.e. controlled) and at least one output beam parameter of the frequency-converted laser beam, the at least one output beam parameter being selected from the group consisting of beam waist size, beam waist location, beam divergence angle, and beam quality factor ([0033] discloses that the output beam position is maintained at a desired position, i.e. controlled, this means that at least the output beam parameter “beam waist location” is controlled and maintained at the desired location; [0039] also states that the temperature tuning changes the beam position, i.e. it changes the beam waist location).
There is not necessarily shown imposing a loss on the intracavity laser beam. Irikuchi teaches that a diode pumped frequency converted laser may further include an etalon 5 that controls the output, compare Figs. 3-5, by imposing a loss via its transmittance. Irikuchi further discusses that the control circuit 12 via temperature regulator keeps etalon temperature, [0030]; a person skilled in the art understands etalons are highly dependent on temperature and thus temperature control controls the loss. It would have been obvious to a person of ordinary skill in the art to control the etalon transmittance in this way as it controls the laser output to be closer to single mode, as taught by Irikuchi. [0013]; [0029].
Regarding claim 2, this is implicitly found in Wang, as the pumping and the lasing will each contribute to thermal lensing in the gain medium, and the contribution from the pump will be higher in the case where a high pump power is used.
Regarding claim 3, Wang may operate in the uv range. [0045].
Regarding claim 4, since Wang may operate in the uv range, see claim 3 rejection, any adjustment will necessarily occur in the presence of uv degradation of the nonlinear crystal.
Regarding claim 6, Wang explicitly describes maintaining the power only, [0033], so it is apparent it could do so while leaving the other parameter unchanged.
Regarding claim 7, Wang is concerned with beam waist location is discussed re: claim 1.
Regarding claim 8, Wang discloses monitoring the frequency-converted laser beam to obtain a measure of the output power (by PSD 46), and the adjusting from the controller 50 is based, at least in part, on the measure of the output power. [0032]-[0033].
Regarding claim 10, again the output beam location is desired to be kept in the same location, so the adjustments are based at least in part on the measure of this parameter.
Regarding claim 19, this is a device claim but the features are taught by Wang and Irikiuchi as discussed above in the rejection of claim 1, which discusses all of the corresponding structure.
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Irikuchi in view of US 2008/0259969 (“Piper”).
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Wang and Irikuchi as applied to claim 1, and further in view of Piper.
Regarding claim 5, the primary references show the features of claim 1 as above, but it is not shown that the nonlinear crystal is shifted transversely to the propagation direction of the laser beam, then the output power/parameter are reset after the shift. Piper teaches that it was known for a nonlinear frequency converting medium to be translated transverse to the incoming laser beam. [0009], [0160]. It would have been obvious to a person of ordinary skill in the art to do so as with certain types of nonlinear medium that permits tuning the wavelength of the beam, as taught by Piper.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Irikuchi in view of US 2019/0089119 (“Lu”).
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Wang and Irikuchi as applied to claim 1, and further in view of Lu.
Regarding claim 9, the primary references show the features of claim 1 as above, but it is not shown that the intracavity laser beam is monitored to obtain a measure of power of the intracavity laser beam, wherein adjustment of the pump power in the adjusting step is further based on the measure of the power of the intracavity laser beam. As noted above re: parent claim 8 the primary references monitor the output beam for this purpose. Lu shows a laser with frequency converter and an intracavity beam is monitored to obtain power so that adjustments can be provided. [0024]-[0025], photodetector 12. It would have been obvious to a person of ordinary skill in the art that the monitoring could be done here instead as a simple substitution of one element for another to yield predictable results. MPEP 2143 I.B. The base device of the primary references monitor the output of the output to determine if changes should be made, but Lu instead monitors intracavity like the claim. A person skilled in the art could have used this instead of the other way and the result of doing that would have been predictable. Monitoring is monitoring and is predictable no matter where in the system it happens. As long as you know what is happening in the system and what you want to happen, based on what you have detected, then monitoring and adjusting would have been predictable, whether it is done at the output or intracavity. It would have been obvious to a person of ordinary skill in the art to do one rather than the other.
Claims 11 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Irikuchi in view of US 2010/0002732 (“Tidemand-Lichtenberg”).
Claims 11, 13, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Wang and Irikuchi as applied to claim 1, and further in view of Tidemand-Lichtenberg.
Regarding claims 11 and 20, the parent claims are taught as above, but it is not taught that there is also the step of superimposing a second laser beam on the intracavity laser beam in the nonlinear crystal to generate the frequency-converted laser beam from mixing of the intracavity laser beam with the second laser beam, or as in claim 20 a second laser for delivering a second laser beam to the nonlinear crystal to mix with the intracavity laser beam so as to generate the frequency-converted laser beam. Tidemand-Lichtenberg teaches in Fig. 1 that it is known to include two separate lasers at 121,122 delivering a second laser superimposed in a laser cavity on a nonlinear crystal to generate a frequency converted beam from mixing the two laser beams. It would have been obvious to a person of ordinary skill in the art to use two lasers as in Tidemand-Lichenberg to provide for sum or difference frequency generation, another type of nonlinear conversion that is often used. [0002]. Really it just depends on what type of output or application is desired, as sum frequency generation is useful in particular applications, and thus it would be obvious to use two lasers in such situation.
Regarding claim 13, Wang may operate in the uv range. [0045].
Claim 12 is rejected under 35 U.S.C. 103 as being unpatentable over Irikuchi and Tidemand-Lichenberg as applied to claim 11, and further in view of Piper.
Claim 12 is rejected under 35 U.S.C. 103 as being unpatentable over Wang, Irikuchi, and Tidemand-Lichenberg as applied to claim 11, and further in view of Piper.
Regarding claim 12, there is not taught in the primary references that the superimposing step includes focusing the second laser beam to a waist in the nonlinear crystal; and the adjusting step includes matching size and location of a waist of the intracavity laser beam to size and location of a waist of the second laser beam. Piper teaches that it was known in the art to match the pump laser beam waist with the cavity laser beam waist. [0107]. It would have been obvious to a person of ordinary skill in the art to do so as this helps to achieve optimal power, as taught by Piper.
Allowable Subject Matter
Claims 14-18 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Regarding claim 14, there is not taught or disclosed in the prior art the method for intracavity frequency conversion as found in claim 1, where the imposing step includes out-coupling a fraction of the intracavity laser beam from the laser resonator. It is of course known to control how to outcouple light from a laser cavity. But note that in claim 1 the imposing step is imposing a loss on the intracavity laser beam, and this loss is adjusted to control the output power and at least one of four particular output beam parameters as claimed, so this is further limiting that step. There is not shown the method of intracavity frequency conversion of claim 1 where the laser output coupling as in claim 14 is adjusted to adjust the loss and control these particular parameters as in claim 1.
For example, WO 2014/012847 describes a frequency converted laser having an outcoupling mirror 5 that outcouples part of the laser beam A, which adjusts how much frequency converted beam B gets output. This can be adjusted by modulator 10,11,21, changing the polarization of the beam to change the amount outcoupled at A (and B). This will adjust the output power. But there is no indication that this is adjusted to control the beam waist size, beam waist location, divergence angle, or quality factor as claimed.
Claims 15-18 depend from claim 14 and are allowable for the same reasons.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to James Menefee whose telephone number is (571)272-1944. The examiner can normally be reached M-F 7-4.
Examiner interviews are available via telephone and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, MinSun Harvey can be reached at (571) 272-1835. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of applications may be obtained from Patent Center. See: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/JAMES A MENEFEE/Primary Examiner, Art Unit 2828