Abstract

A new method is presented for measuring the absorptance of evaporated metal films as a function of wavelength with a possible precision of ±1.4%. The sample consists of a temperature-sensitive quartz crystal which is plated on both sides with the metal film. The small temperature rise of the plated crystal due to the energy absorbed from the incident beam of radiation is measured by monitoring the frequency change of the quartz crystal when it is driven in an oscillator. The absorptance, relative to a black surface, is determined from frequency rates at a particular temperature as the crystal goes through a heating and cooling cycle. Results are given on the absorptance of an aluminum film at room temperature as a function of wavelength between 0.45 and 2 μ.

© 1966 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. P. Drude, Theory of Optics (Longmans Green and Co., Inc., New York, 1902).
  2. P. Drude, Ann. Physik 14, 677, 936 (1904).
    [Crossref]
  3. H. E. Bennett, J. M. Bennett, and E. J. Ashley, J. Opt. Soc. Am. 52, 1245 (1962).
    [Crossref]
  4. R. A. Heising, Quartz Crystals for Electrical Circuits (D. Van Nostrand Co., Inc., New York, 1946).
  5. W. P. Mason, Electromechanical Transducers and Wave Filters (D. Van Nostrand Co., Inc., Princeton, New Jersey, 1942).
  6. RCA Transistor Manual (RCA Semiconductor and Materials Division, Somerville, New Jersey, 1962), p. 38.
  7. D. K. Edwards, J. T. Gier, K. E. Nelson, and R. D. Roddick, J. Opt. Soc. Am. 51, 1279 (1961).
    [Crossref]
  8. W. M. Brandenberg, J. Opt. Soc. Am. 54, 1235 (1964).
    [Crossref]
  9. G. Hass and J. E. Waylonis, J. Opt. Soc. Am. 51, 719 (1961).
    [Crossref]

1964 (1)

1962 (1)

1961 (2)

1904 (1)

P. Drude, Ann. Physik 14, 677, 936 (1904).
[Crossref]

Ann. Physik (1)

P. Drude, Ann. Physik 14, 677, 936 (1904).
[Crossref]

J. Opt. Soc. Am. (4)

Other (4)

P. Drude, Theory of Optics (Longmans Green and Co., Inc., New York, 1902).

R. A. Heising, Quartz Crystals for Electrical Circuits (D. Van Nostrand Co., Inc., New York, 1946).

W. P. Mason, Electromechanical Transducers and Wave Filters (D. Van Nostrand Co., Inc., Princeton, New Jersey, 1942).

RCA Transistor Manual (RCA Semiconductor and Materials Division, Somerville, New Jersey, 1962), p. 38.

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

Optical schematic of absorptance apparatus. The components are: (1) quartz prism monochromator, (2) tungsten lamp, (3) beam shutter, (4) spherical collector mirror, (5) vacuum chamber, (6) quartz window, (7) quartz crystal, (8) aluminized hemisphere.

Fig. 2
Fig. 2

Quartz crystal mount with aluminized hemisphere and turning mechanism. The components are: (1) base plate, (2) turning mechanism, (3) electrical lead through, (4) electrical leads, (5) quartz crystal, (6) aluminized hemisphere, (7) entrance port, (8) sample electrode, (9) crystal holder base.

Fig. 3
Fig. 3

Equivalent circuit of a quartz crystal.

Fig. 4
Fig. 4

Transistor crystal oscillator and buffer circuit. All capacitors are given in μμF, resistors in ohms.

Fig. 5
Fig. 5

Heating and cooling curves of quartz crystals for evaporated aluminum (fs,fs′) and blackbody (fb,fb′), λ = 0.8 μ.

Fig. 6
Fig. 6

Exponential dependence of heating and cooling curves for aluminum and blackbody, λ = 0.8 μ.

Fig. 7
Fig. 7

Goniometric measurements of benzene-smoke coating showing reflected intensity versus angle of reflection, angle of incidence equals 10°.

Fig. 8
Fig. 8

Absorptance of evaporated aluminum between 0.45 and 2.0 μ, ⊙ present results, — Bennett et al.3

Tables (2)

Tables Icon

Table I Reflectance ρ of hemisphere, absorptance αb of blackbody, and absorptance αs of evaporated aluminum film.

Tables Icon

Table II Thermal properties of benzene-black, aluminum film, and quartz crystal.

Equations (20)

Equations on this page are rendered with MathJax. Learn more.

( m c p ) d T s / d t = α s I 0 + P - K 1 ( T s - T 1 ) - K 2 ( T s - T 2 ) - K 3 ( T s 4 - T 3 4 ) ,
( m c p ) d T s / d t = P - K 1 ( T s - T 1 ) - K 2 ( T s - T 2 ) - K 3 ( T s 4 - T 3 4 ) ,
α s I 0 / ( m c p ) = d T s / d t - d T s / d t ,             T s = T s .
α b I 0 / ( m c p ) = d T b / d t - d T b / d t ,             T b = T b ,
α s / α b = [ d T s / d t - d T s / d t ] T s = T s / [ d T b / d t - d T b / d t ] T b = T b .
( m c p ) d T s / d t = ( α s I 0 + P + K 1 T 1 + K 2 T 2 + 4 K 3 T 3 4 ) - ( K 1 + K 2 + 4 K 3 T 3 3 ) T s .
T s = A s - ( A s - T i ) e - c s ( t - t i ) ,
A s = ( α s I 0 + P + K 1 T 1 + K 2 T 2 + 4 K 3 T 3 4 ) / ( K 1 + K 2 + 4 K 3 T 3 3 ) , c s = ( K 1 + K 2 + 4 K 3 T 3 3 ) / ( m c p ) ,
T = β 0 + β 1 f .
f s = a s - b s e - c s ( t - t i ) ,
a s = ( A s - β 0 ) / β 1 b s = ( A s - T i ) / β 1 .
α s / α b = [ d f s / d t - d f s / d t ] f s = f s / [ d f b / d t - d f b / d t ] f b = f b .
d f s / d t = c s b s e - c s ( t - t i ) = c s ( a s - f s ) .
α s / α b = [ c s ( a s - f s ) - c s ( a s - f s ) ] / [ c b ( a b - f b ) - c b ( a b - f b ) ] .
and             f s = ( a s + a s ) / 2 , f b = ( a b + a b ) / 2.
α s / α b = [ ( c s + c s ) / ( c b + c b ) ] [ ( a s - a s ) / ( a b - a b ) ] .
a = f 1 + b , b = δ 2 2 / ( δ 2 - δ 3 ) , c = ( 1 / Δ t ) ln ( δ 2 / δ 3 ) .
α b = α b b n = 0 j [ ( 1 - α b b ) ρ h ] n ,
α b = α b b [ 1 + ( 1 - α b b ) ρ h ] .
Δ α b / α b ( 1 - ρ h ) ( Δ α b b / α b b ) + ρ h ( 1 - α b b ) ( Δ ρ / ρ ) .