Abstract

Filaments of semicircular cross section (diam 0.25–0.32 mm) were mounted in bulbs with plane windows. Chopped plane-polarized radiant flux was reflected from the flat surface, then passed through an analyzer whose plane of polarization made a 45° angle with the plane of reflection at the filament. The orientation of the polarizer was varied in 45° steps, and wavelengths from 0.47 to 2.0 μ were used. The metals studied were W, Mo, Ta, Ir, Re, Nb, and Pt. Filament temperatures ranged from 300 to 2400–2500°K. (Maximum for Pt was 1900°.) n-vs-λ curves for different temperatures were close together in the visible, but spread apart with increasing wavelength in the infrared. Curves showing k vs λ and e vs λ usually crossed one another near a common point. Deviations from previously published data ranged up to 15 or 20%. Systematic errors in some of the infrared data, due to difficulty in centering the reflecting surface in the beam from the source lamp, are quite obvious. Rough agreement with a simplified form of the Drude theory is approached with increasing wavelength in certain cases.

© 1966 Optical Society of America

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References

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  1. D. G. Avery, Proc. Phys. Soc. (London) 65B, 425 (1952).
    [Crossref]
  2. N≡ n− ik.
  3. J. N. Hodgson, Proc. Phys. Soc. (London) 68B, 593 (1955).
    [Crossref]
  4. J. R. Beattie and G. K. T. Conn, Phil. Mag. 46, 222 (1955); J. R. Beattie, Phil. Mag. 46, 235 (1955).
  5. For references to Drude’s articles and a discussion of the advantages of the theory based on two types of free-charge carriers, see S. Roberts, Phys. Rev. 100, 1667 (1955).
    [Crossref]

1955 (3)

J. N. Hodgson, Proc. Phys. Soc. (London) 68B, 593 (1955).
[Crossref]

J. R. Beattie and G. K. T. Conn, Phil. Mag. 46, 222 (1955); J. R. Beattie, Phil. Mag. 46, 235 (1955).

For references to Drude’s articles and a discussion of the advantages of the theory based on two types of free-charge carriers, see S. Roberts, Phys. Rev. 100, 1667 (1955).
[Crossref]

1952 (1)

D. G. Avery, Proc. Phys. Soc. (London) 65B, 425 (1952).
[Crossref]

Avery, D. G.

D. G. Avery, Proc. Phys. Soc. (London) 65B, 425 (1952).
[Crossref]

Beattie, J. R.

J. R. Beattie and G. K. T. Conn, Phil. Mag. 46, 222 (1955); J. R. Beattie, Phil. Mag. 46, 235 (1955).

Conn, G. K. T.

J. R. Beattie and G. K. T. Conn, Phil. Mag. 46, 222 (1955); J. R. Beattie, Phil. Mag. 46, 235 (1955).

Hodgson, J. N.

J. N. Hodgson, Proc. Phys. Soc. (London) 68B, 593 (1955).
[Crossref]

Roberts, S.

For references to Drude’s articles and a discussion of the advantages of the theory based on two types of free-charge carriers, see S. Roberts, Phys. Rev. 100, 1667 (1955).
[Crossref]

Phil. Mag. (1)

J. R. Beattie and G. K. T. Conn, Phil. Mag. 46, 222 (1955); J. R. Beattie, Phil. Mag. 46, 235 (1955).

Phys. Rev. (1)

For references to Drude’s articles and a discussion of the advantages of the theory based on two types of free-charge carriers, see S. Roberts, Phys. Rev. 100, 1667 (1955).
[Crossref]

Proc. Phys. Soc. (London) (2)

D. G. Avery, Proc. Phys. Soc. (London) 65B, 425 (1952).
[Crossref]

J. N. Hodgson, Proc. Phys. Soc. (London) 68B, 593 (1955).
[Crossref]

Other (1)

N≡ n− ik.

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Figures (7)

Fig. 1
Fig. 1

Diagram of optical setup. S, source lamp; C, chopper; T, test lamp; L, achromatic lens; D, diaphragm; P, polarizer; A, analyzer; and M, monochromator.

Fig. 2
Fig. 2

Test lamp with filament of semicircular cross section and tantalum leads to upper end of filament.

Fig. 3
Fig. 3

Optical constants vs wavelength, at various filament temperatures for molybdenum and tungsten.

Fig. 4
Fig. 4

Optical constants for niobium and tantalum.

Fig. 5
Fig. 5

Optical constants vs wavelength for rhenium and iridium. Parameter, filament temperature.

Fig. 6
Fig. 6

Above: Spectral emissivity of niobium and tantalum. Below: Optical constants vs wavelength for platinum.

Fig. 7
Fig. 7

Spectral emissivity data obtained on molybdenum, tungsten, iridium, and rhenium filaments.

Tables (1)

Tables Icon

Table I Comparison of spectral emissivity and optical constants values from other sources with those read from Figs. 3 and 7.