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 .
Specification
The specification is objected to as failing to provide proper antecedent basis for the claimed subject matter. See 37 CFR 1.75(d)(1) and MPEP § 608.01(o). Correction of the following is required: specification should recite that the laser beam is focused so that each pulse of the laser pulse train reaches an illumination greater than 1018 Wcm-2, as claimed in claim 8, or claim 8 should be amended to bring it in line with the specification. The specification states a different value, 1017 Wcm-2. (“According to a characteristic of the invention, the laser beam can be focused so that each pulse of the laser pulse train reaches an illuminance greater than 1017 Wcm−2 in the gas cloud.” P 34).
Claim Interpretation
The independent claim recites “a step of generating at least one laser pulse that is focused into the gas cloud so as to create a plasma”. This limitation is considered to be a recitation of steps of generating at least one laser pulse (1st step) and focusing it into a gas cloud (2nd step). The phrase “so as to create a plasma” does not add any additional steps or add any meaningful limitations to the steps of generating and focusing the laser beam. In adherence with United States patent law, a clause in a method claim will not be given patentable weight if it merely recites an intended result. See ‘whereby clause in a method claim is not given weight when it simply expresses the intended result of a process step positively recited.’ Id. (quoting Minton v. Nat’l Ass’n of Securities Dealers, Inc., 336 F.3d 1373, 1381, 67 USPQ2d 1614, 1620 (Fed. Cir. 2003)). In this case, the phrasing “so as to” clearly links the creation of the plasma to the already recited steps.
Claim 1 also recited a step of setting a delay between successive pulses in a laser pulse train based on a plasma period that is a function of a plasma electron density n, and claim 10 further specifies that the method is “characterized in that the plasma electron density n is comprised between 1018 cm-3 and 1021 cm-3.” Claim 10 can therefore be considered to set boundaries on the plasma period and therefore the delay setting step, but does not actually require the presence of a plasma with the specified plasma electron density, because the creation of such a plasma is merely an intended result. In particular, the claimed electron density correlates to a plasma period between 113 fs and 3.5 fs, or a delay between two successive pulses of 10.5 fs to 3.39 ps.
Claims 11 and 12 both recite producing a gas cloud pulsed “at a frequency of the laser pulse”. This would appear to require the gas to be pulsed at a rate on the order of giga or terahertz, which is beyond the capabilities of state-of-the-art gas injectors. However, claim 12 further specifies that the gas cloud is emitted “at a frequency … with an opening duration greater than 1 ms.” Furthermore the specification states,
For each pulse train, the gas is ionized by the rising edge of the first pulse of the train. Then, all the other laser pulses of the train directly see a plasma. Each pulse train encounters a new gas cloud, for example every s, 10 ms, or 100 ms, etc. according to the cadence.
Based on this, examiner believes applicant is intending to claim producing a gas in a pulsed manner with pulses having a duration of 1 ms or longer. Examiner will interpret the claims accordingly for comparison to the prior art. Examiner will also make the required 112(a) rejections because producing gas “in a pulsed manner at a frequency of the laser pulse” is not enabled, and a 112(b) rejection of claim 12, for having two incompatible limitations.
Claim Rejections - 35 USC § 112(a)
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 11-12 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the enablement requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to enable one skilled in the art to which it pertains, or with which it is most nearly connected, to make and/or use the invention.
Claims 11-12 recite a gas cloud produced “in a pulsed fashion at the frequency of the laser pulses.” The laser pulses are disclosed as being spaced by approximately 100 femtoseconds or less (“Unlike the prior art, rather than a single high-energy pulse, a pulse train is used, with a delay between two pulses of the order of approximately one hundred femtoseconds for example.” Also, “Beyond 40 pulses, it is possible to envisage for example an operation with low peak power with pulses of a few femtoseconds.”). State of the art gas injectors generally operate on millisecond time scales, though durations on the order of microseconds are possible for high pressure jets. Even the microsecond time scales are still several orders of magnitude slower than the required hundreds of femtoseconds. The specification does not include details of an inventive gas injector and there is no reason to believe the generically disclosed gas injector would be capable of such rapid gas pulsing.
Claim Rejections - 35 USC § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-9 & 11-15 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites “generating a laser pulse train with a delay between two successive laser pulses comprised between three times and thirty times the plasma period Tp, such that:
T
p
=
λ
p
c
λp being the plasma wavelength defined by:
λ
p
=
2
π
c
*
n
e
2
m
ε
o
-
1
/
2
where c is the light celerity, n is the plasma electron density in cm-3, e=1.6e-19 C is the electron charge, m=9.1e-31 kg is the electron mass, and εo = 8.85 x 10-12 m-3 kg-1 s4 A2 is the vacuum permittivity.”
The delay is claimed as a function of a plasma period, but the plasma period will depend on the plasma electron density, which is both unspecified and variable depending on gas species and pressure, neither of which is claimed to be known, controlled, or determined. It is therefore impossible to determine the length of delay required to meet the limitation. It is noted that claim 10 does specify the plasma electron density and therefore is not rejected on these grounds.
Claims 8 and 11-13 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 8 recites an “illumination” of a laser pulse in units of Wcm-2. The term illumination is generally used when considering only visible light and expressed in lux or lumens per area, taking into account the spectrum of light and its perceived brightness. It appears applicant intends to claim irradiance.
Also regarding claim 8, the claim recites a method “characterized in that the laser beam is focused so that each pulse of the laser pulse train reaches an illumination greater than 1018 Wcm-2 in the gas cloud”. This is not a proper recitation of a method step or function, but an intended result of the previously claimed focusing step.
Claim 11 recites the method “characterized in that the gas cloud is produced either continuously or in pulsed fashion at the frequency of the laser pulse.” No method step of producing a gas cloud is claimed, only steps for generating and focusing laser pulses, therefore it is unclear what it means for a method to be “characterized in that” the gas cloud is produced in such a manner. It is suggested that applicant amend to positively recite the relevant process step, for example, by amending the claim to recite a method “further comprising a step of producing a gas cloud either continuously or in pulsed fashion at the frequency of the laser pulse.”
Claim 12 recites a method “characterized in that the gas cloud is emitted in pulsed fashion at the frequency of the laser pulses with an opening duration greater than 1 ms.” The claim appears to require two different pulsing durations/frequencies. On the one hand, the claim specifies that the pulsing is done “at the frequency of the laser pulses” which correlates with a duration on the order of femtoseconds to picoseconds, and on the other “with an opening duration greater than 1 ms.”
Claim 13 recites the method “characterized in that the plasma length is comprised between 0.02 mm and 100 mm.” This is not a proper recitation of a method step or function, but an intended result of the previously claimed steps.
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.
Claim(s) 1-10 and 13-15 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by “Excitation and Control of Plasma Wakefields by Multiple Laser Pulses” (Cowley et al.).
Regarding claim 1, Cowley et al. disclose a method for producing energetic electron beams by means of a laser-plasma accelerator comprising a laser and a device for generating a gas cloud in a vacuum chamber, the method comprising; a step of generating at least one laser pulse that is focused into the gas cloud so as to create a plasma (‘The pulse train was directed to an f =1 m off-axis paraboloid, used at f/18, which focused the pulses through a hydrogen gas cell;’); generating at least one laser pulse including at least generating a laser pulse train (‘Single, temporally chirped pulses from the laser system were converted into pulse trains by placing a Michelson interferometer between the final laser amplifier and its vacuum compressor,’) with a delay between two successive laser pulses comprised between three times and thirty times the plasma period Tp, such that:
T
p
=
λ
p
c
λp being the plasma wavelength defined by:
λ
p
=
2
π
c
*
n
e
2
m
ε
o
-
1
/
2
where c is the light celerity, n is the plasma electron density in cm-3, e=1.6e-19 C is the electron charge, m=9.1e-31 kg is the electron mass, and εo = 8.85 x 10-12 m-3 kg-1 s4 A2 is the vacuum permittivity (fig. 3(b) & (c) and associated text, showing delay between successive laser pulse of 420fs and 112fs, respectively).
Regarding claim 2, Cowley et al. discloses the method according to claim 1, characterized in that the duration of each pulse is comprised between 5 femtoseconds and 100 femtoseconds (“The fit yields τ0 = (49 ± 8) fs, which is consistent with the value of τ0 = (46 ± 7) fs measured with the SSA.”).
Regarding claim 3, Cowley et al. discloses the method according to claim 1, characterized in that the total number of pulses in the laser pulse train is comprised between 2 and 200 (fig. 3b,c uses N = 2 and 7, also discloses that N up to 80 are possible “we note that our previous particle-in-cell simulations [21] show (for a hydrogen pressure of 3.6 mbar) that linear growth of the wake amplitude with 𝑁 could be maintained for trains of up to 𝑁 =80.”).
Regarding claim 4, Cowley et al. discloses the method according to claim 1, characterized in that the total laser energy is comprised between 100 mJ and 20J (“E = 160 mJ,”).
Regarding claim 5, Cowley et al. discloses the method according to claim 1, characterized in that the energy laser pulse is comprised between 25mJ and 2J (total E for pulse train is 160mJ “E = 160 mJ,” for N = 2 pulses, hence energy per pulse is 80mJ).
Regarding claim 6, Cowley et al. discloses the method according to claim 1, characterized in that the laser emits a laser beam having a wavelength of 800 nm (“a center wavelength λ0 = 800 nm”).
Regarding claim 7, Cowley et al. discloses the method according to claim 1, characterized in that all the laser pulses have one and the same wavelength or different wavelengths comprising a wavelength and harmonics (“identical driving pulses”).
Regarding claim 8, Cowley et al. discloses the method according to claim 1, characterized in that the laser beam is focused so that each pulse of the laser pulse train reaches an illumination greater than 1018 Wcm-2 in the gas cloud (intended result and therefore non-limiting).
Regarding claim 9, Cowley et al. discloses the method according to claim 1, characterized in that the gas comprises one or a mixture of the following gases: He, H2, Ar, N2 (“hydrogen gas cell”).
Regarding claim 10, Cowley et al. discloses the method according to claim 1, characterized in that the plasma electron density n is comprised between 1018 cm-3 and 1021 cm-3. As explained in the claim interpretation section, this will be interpreted to mean the pulse train is generated with a delay between two successive pulses of 10.5 fs to 3.39 ps, which is disclosed in Cowley et al. (fig. 3(b) & (c) and associated text, showing delay between successive laser pulse of 420fs and 112fs, respectively).
Regarding claim 13, Cowley et al. discloses the method according to claim 1, characterized in that the plasma length is comprised between 0.02 mm and 100 mm (intended result, note also “focused the pulses through a hydrogen gas cell; this was 3 mm long,”).
Regarding claim 14, Cowley et al. discloses a laser-plasma accelerator for producing energetic electron beams by implementing the method according to claim 1; the laser-plasma accelerator comprising: a laser for emitting a laser beam a laser compressor; a splitter of the laser beam into a pulse train; a device for producing a gas cloud in a vacuum chamber; and focusing optics (fig. 1).
Regarding claim 15, Cowley et al. discloses the laser-plasma accelerator according to claim 14, characterized in that said laser is a laser incorporating the chirped pulse amplification technique (CPA) (“Single, temporally chirped pulses from the laser system were converted into pulse trains”).
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.
Claim(s) 11-12 is/are rejected under 35 U.S.C. 103 as being unpatentable over “Excitation and Control of Plasma Wakefields by Multiple Laser Pulses” (Cowley et al.).
Regarding claim 11, Cowley et al. discloses the claimed invention except is it silent as to whether the gas cloud is produced either continuously or in pulsed fashion at the frequency of the laser pulses. Methods of producing gas clouds both continuously and in a pulsed manner are well known in the art, and it would have been obvious to a person having ordinary skill in the art at the time the application was filed to modify the method to include production of the gas in such a manner so that the gas pressure at the could be controlled to provide the desired electron density.
Regarding claim 12, Cowley et al. discloses the claimed invention except for gas cloud being emitted in pulsed fashion at the frequency of the laser pulses with an opening duration greater than 1 ms. Methods of producing gas clouds in a pulsed manner are well known in the art, and it would have been obvious to a person having ordinary skill in the art at the time the application was filed to modify the method of Cowley to emit the gas cloud in a pulsed fashion with an opening duration greater than 1ms to avoid wasting gas and increasing the pressure in the vacuum cell by producing gas between pulse trains.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ELIZA W OSENBAUGH-STEWART whose telephone number is (571)270-5782. The examiner can normally be reached 10am - 6pm Pacific Time M-F.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Robert Kim can be reached at 571-272-2293. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/ELIZA W OSENBAUGH-STEWART/Primary Examiner, Art Unit 2881
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