Abstract

We have measured 527-nm absorption for induced spatial incoherence (ISI) and non-ISI illumination of high-Z targets over the 0.5–3.5 × 1014-W/cm2 laser intensity range using energy balance with a custom designed 30-cm diam light integrating sphere. Induced spatial incoherence of the laser beam was produced by inserting echelons in the beam path and operating the laser at wide bandwidth (0.2%). To produce ISI and non-ISI data for comparison, we irradiated a large number of 180-μm diam gold disks with 0.5–1.5-ns pulses with echelons in the beam path with and without wide laser bandwidths. Our data show an increase in absorption of 5–11% for the ISI illuminated targets and also suggest a weaker dependence of absorption on laser intensity for ISI illumination than for non-ISI.

© 1990 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. R. H. Lehmberg, S. P. Obenschain, “Use of Induced Spatial Incoherence for Uniform Illumination of Laser Fusion Targets,” Opt. Commun. 46, 27–31 (1983).
    [Crossref]
  2. S. P. Obenschain et al., “Laser–Target Interaction with Induced Spatial Incoherence,” Phys. Rev. Lett. 56, 2807–2809 (1986).
    [Crossref] [PubMed]
  3. A. N. Mostovych et al., “Brillouin-Scattering Measurements from Plasmas Irradiated with Spatially and Temporally Incoherent Laser Light,” Phys. Rev. Lett. 59, 1193–1196 (1987).
    [Crossref] [PubMed]
  4. D. R. Kania, P. Bell, S. P. Obenschain, “Effects of ISI on the Interaction of 1.05 μm Light with High Z Plasmas,” Proc. Soc. Photo-Opt. Instrum. Eng. 913, 98 (1988).
  5. J. D. Simpson, D. J. Drake, T. Speziale, “Light-Integrating Cylinder for ICF Light Balance Measurements in Mirror Illumination Systems,” Rev. Sci. Instrum. 57, 2951–2956 (1986).
    [Crossref]
  6. J. P. Anthes, M. A. Palmer, M. A. Gusinow, M. D. Matzen, “Absorption of Laser Radiation by Al, Fe, and Au Planar Metallic Targets,” Appl. Phys. Lett. 34, 841–843 (1979).
    [Crossref]
  7. R. P. Godwin, R. Sachsenmaier, R. Sigel, “Angle-Dependent Reflectance of Laser-Produced Plasmas,” Phys. Rev. Lett. 39, 1198–1201 (1977).
    [Crossref]
  8. R. Kristal, “Surface Plasma Absorption in an Integrating Sphere at High Optical Flux Levels,” Appl. Opt. 21, 1885–1887 (1982).
    [Crossref] [PubMed]
  9. Catalog LBS-004, Labsphere, Inc., P.O. Box 70, North Sutton, NH 03260.

1988 (1)

D. R. Kania, P. Bell, S. P. Obenschain, “Effects of ISI on the Interaction of 1.05 μm Light with High Z Plasmas,” Proc. Soc. Photo-Opt. Instrum. Eng. 913, 98 (1988).

1987 (1)

A. N. Mostovych et al., “Brillouin-Scattering Measurements from Plasmas Irradiated with Spatially and Temporally Incoherent Laser Light,” Phys. Rev. Lett. 59, 1193–1196 (1987).
[Crossref] [PubMed]

1986 (2)

S. P. Obenschain et al., “Laser–Target Interaction with Induced Spatial Incoherence,” Phys. Rev. Lett. 56, 2807–2809 (1986).
[Crossref] [PubMed]

J. D. Simpson, D. J. Drake, T. Speziale, “Light-Integrating Cylinder for ICF Light Balance Measurements in Mirror Illumination Systems,” Rev. Sci. Instrum. 57, 2951–2956 (1986).
[Crossref]

1983 (1)

R. H. Lehmberg, S. P. Obenschain, “Use of Induced Spatial Incoherence for Uniform Illumination of Laser Fusion Targets,” Opt. Commun. 46, 27–31 (1983).
[Crossref]

1982 (1)

1979 (1)

J. P. Anthes, M. A. Palmer, M. A. Gusinow, M. D. Matzen, “Absorption of Laser Radiation by Al, Fe, and Au Planar Metallic Targets,” Appl. Phys. Lett. 34, 841–843 (1979).
[Crossref]

1977 (1)

R. P. Godwin, R. Sachsenmaier, R. Sigel, “Angle-Dependent Reflectance of Laser-Produced Plasmas,” Phys. Rev. Lett. 39, 1198–1201 (1977).
[Crossref]

Anthes, J. P.

J. P. Anthes, M. A. Palmer, M. A. Gusinow, M. D. Matzen, “Absorption of Laser Radiation by Al, Fe, and Au Planar Metallic Targets,” Appl. Phys. Lett. 34, 841–843 (1979).
[Crossref]

Bell, P.

D. R. Kania, P. Bell, S. P. Obenschain, “Effects of ISI on the Interaction of 1.05 μm Light with High Z Plasmas,” Proc. Soc. Photo-Opt. Instrum. Eng. 913, 98 (1988).

Drake, D. J.

J. D. Simpson, D. J. Drake, T. Speziale, “Light-Integrating Cylinder for ICF Light Balance Measurements in Mirror Illumination Systems,” Rev. Sci. Instrum. 57, 2951–2956 (1986).
[Crossref]

Godwin, R. P.

R. P. Godwin, R. Sachsenmaier, R. Sigel, “Angle-Dependent Reflectance of Laser-Produced Plasmas,” Phys. Rev. Lett. 39, 1198–1201 (1977).
[Crossref]

Gusinow, M. A.

J. P. Anthes, M. A. Palmer, M. A. Gusinow, M. D. Matzen, “Absorption of Laser Radiation by Al, Fe, and Au Planar Metallic Targets,” Appl. Phys. Lett. 34, 841–843 (1979).
[Crossref]

Kania, D. R.

D. R. Kania, P. Bell, S. P. Obenschain, “Effects of ISI on the Interaction of 1.05 μm Light with High Z Plasmas,” Proc. Soc. Photo-Opt. Instrum. Eng. 913, 98 (1988).

Kristal, R.

Lehmberg, R. H.

R. H. Lehmberg, S. P. Obenschain, “Use of Induced Spatial Incoherence for Uniform Illumination of Laser Fusion Targets,” Opt. Commun. 46, 27–31 (1983).
[Crossref]

Matzen, M. D.

J. P. Anthes, M. A. Palmer, M. A. Gusinow, M. D. Matzen, “Absorption of Laser Radiation by Al, Fe, and Au Planar Metallic Targets,” Appl. Phys. Lett. 34, 841–843 (1979).
[Crossref]

Mostovych, A. N.

A. N. Mostovych et al., “Brillouin-Scattering Measurements from Plasmas Irradiated with Spatially and Temporally Incoherent Laser Light,” Phys. Rev. Lett. 59, 1193–1196 (1987).
[Crossref] [PubMed]

Obenschain, S. P.

D. R. Kania, P. Bell, S. P. Obenschain, “Effects of ISI on the Interaction of 1.05 μm Light with High Z Plasmas,” Proc. Soc. Photo-Opt. Instrum. Eng. 913, 98 (1988).

S. P. Obenschain et al., “Laser–Target Interaction with Induced Spatial Incoherence,” Phys. Rev. Lett. 56, 2807–2809 (1986).
[Crossref] [PubMed]

R. H. Lehmberg, S. P. Obenschain, “Use of Induced Spatial Incoherence for Uniform Illumination of Laser Fusion Targets,” Opt. Commun. 46, 27–31 (1983).
[Crossref]

Palmer, M. A.

J. P. Anthes, M. A. Palmer, M. A. Gusinow, M. D. Matzen, “Absorption of Laser Radiation by Al, Fe, and Au Planar Metallic Targets,” Appl. Phys. Lett. 34, 841–843 (1979).
[Crossref]

Sachsenmaier, R.

R. P. Godwin, R. Sachsenmaier, R. Sigel, “Angle-Dependent Reflectance of Laser-Produced Plasmas,” Phys. Rev. Lett. 39, 1198–1201 (1977).
[Crossref]

Sigel, R.

R. P. Godwin, R. Sachsenmaier, R. Sigel, “Angle-Dependent Reflectance of Laser-Produced Plasmas,” Phys. Rev. Lett. 39, 1198–1201 (1977).
[Crossref]

Simpson, J. D.

J. D. Simpson, D. J. Drake, T. Speziale, “Light-Integrating Cylinder for ICF Light Balance Measurements in Mirror Illumination Systems,” Rev. Sci. Instrum. 57, 2951–2956 (1986).
[Crossref]

Speziale, T.

J. D. Simpson, D. J. Drake, T. Speziale, “Light-Integrating Cylinder for ICF Light Balance Measurements in Mirror Illumination Systems,” Rev. Sci. Instrum. 57, 2951–2956 (1986).
[Crossref]

Appl. Opt. (1)

Appl. Phys. Lett. (1)

J. P. Anthes, M. A. Palmer, M. A. Gusinow, M. D. Matzen, “Absorption of Laser Radiation by Al, Fe, and Au Planar Metallic Targets,” Appl. Phys. Lett. 34, 841–843 (1979).
[Crossref]

Opt. Commun. (1)

R. H. Lehmberg, S. P. Obenschain, “Use of Induced Spatial Incoherence for Uniform Illumination of Laser Fusion Targets,” Opt. Commun. 46, 27–31 (1983).
[Crossref]

Phys. Rev. Lett. (3)

S. P. Obenschain et al., “Laser–Target Interaction with Induced Spatial Incoherence,” Phys. Rev. Lett. 56, 2807–2809 (1986).
[Crossref] [PubMed]

A. N. Mostovych et al., “Brillouin-Scattering Measurements from Plasmas Irradiated with Spatially and Temporally Incoherent Laser Light,” Phys. Rev. Lett. 59, 1193–1196 (1987).
[Crossref] [PubMed]

R. P. Godwin, R. Sachsenmaier, R. Sigel, “Angle-Dependent Reflectance of Laser-Produced Plasmas,” Phys. Rev. Lett. 39, 1198–1201 (1977).
[Crossref]

Proc. Soc. Photo-Opt. Instrum. Eng. (1)

D. R. Kania, P. Bell, S. P. Obenschain, “Effects of ISI on the Interaction of 1.05 μm Light with High Z Plasmas,” Proc. Soc. Photo-Opt. Instrum. Eng. 913, 98 (1988).

Rev. Sci. Instrum. (1)

J. D. Simpson, D. J. Drake, T. Speziale, “Light-Integrating Cylinder for ICF Light Balance Measurements in Mirror Illumination Systems,” Rev. Sci. Instrum. 57, 2951–2956 (1986).
[Crossref]

Other (1)

Catalog LBS-004, Labsphere, Inc., P.O. Box 70, North Sutton, NH 03260.

Cited By

OSA participates in Crossref's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (8)

Fig. 1
Fig. 1

Schematic diagram of the experimental setup during ISI absorption experiments showing the integrating sphere and other required diagnostics.

Fig. 2
Fig. 2

Schematic of the 30-cm diam integrating sphere used to measure scattered light. The diagram shows the diffuser placement for calibration shots as well as the baffles used to prevent direct viewing of the target by the photodiodes. The sphere is hinged to allow interior access for target and diffuser insertion and removal.

Fig. 3
Fig. 3

Integrating sphere calibration response as a function of shot order. The top curve is the front diode response, while the lower curve is the rear diode response. Each data set is fitted with a third-order polynomial.

Fig. 4
Fig. 4

Signal ratio between rear Vr and front Vf photodiodes for calibration (circles) and target (stars) shots. The lines are polynomial fits of the calibration and target shot data points.

Fig. 5
Fig. 5

Ratio of scattered energy as measured by rear Er and front Ef diodes. The line is a polynomial fit of the data.

Fig. 6
Fig. 6

Raw data plot of the absorbed energy fraction as a function of the laser intensity on the target. Data are fitted with second-order polynomials with the upper curve representing wideband (ISI) and the lower curve representing narrowband (non-ISI) response. Error bars represent measurement uncertainty for the diagnostics and recording instruments used.

Fig. 7
Fig. 7

Smoothed data plot of absorbed energy fraction vs intensity. All absorption values within a 10% intensity range were averaged, and error bars were determined from the resulting standard deviations.

Fig. 8
Fig. 8

Increase in absorption with ISI as a function of incident laser intensity. The curve is a point by point difference between the polynomials shown in Fig. 7.

Tables (2)

Tables Icon

Table I Calibration Shot Data

Tables Icon

Table II Target Shot Area

Metrics