The atomic-iodine hyperfine structure is shown to produce anomalous dispersion
effects on its hyperfine laser transition at 1.315 μm
whenever reasonable small-signal gains are available (~1% cm). This
dispersion effect is linearly dependent on the iodine inversion density. Such an
anomalous dispersion effect may produce strong phase-induced mode–media
interactions for all the lower-gain iodine hyperfine transitions in any low
pressure (<50 Torr) atomic-iodine laser. Fortunately, the highest-gain
hyperfine transition, F′ = 3 →
F″ = 4, has the smallest amount of
additional phase shift (or refractivity) introduced by this anomalous
dispersion. All the other transitions experience much larger anomalous
dispersion effects. This condition should act as an internal frequency
discriminator, forcing the iodine to lase on the highest-gain hyperfine
transition.
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F′ is the upper-state quantum number, whereas
F″ refers to the lower-state quantum
number.
Ref. 23.
Refs. 15 and 16. Values calculated by methods described in
text.
Table 2
Pressure-Broadening Coefficients
νPB (MHz/Torr)
for Various Buffer Gases
Stimulated-Emission Cross Section
σse in Units of
10−18 cm2 for each Atomic-Iodine Hyperfine
Transition as a Function of Total Pressure Broadening
Δν in Megahertza
Phase Shifts Δϕ (deg/m) per Meter Length for
Inversion Density of [NuT −
(NlT/2)] =
1016/cm3 as Function of Total Lorentz Broadening
in Megahertza
Δν
(MHz)
2–3
2–2
2–1
3–4
3–3
3–2
1
−5.785 (−2.114)
−5.166 (−1.887)
8.208 (2.999)
−0.5319 (−0.3110)
3.177 (1.161)
5.779 (2.111)
2.5
−5.785 (−2.114)
−5.166 (−1.887)
8.208 (2.999)
−0.5319 (−0.3110)
3.177 (1.161)
5.779 (2.111)
5
−5.785 (−2.114)
−5.165 (−1.887)
8.208 (2.999)
−0.5319 (−0.3110)
3.177 (1.161)
5.779 (2.111)
10
−5.785 (−2.114)
−5.165 (−1.887)
8.207 (2.999)
−0.5319 (−0.3110)
3.177 (1.161)
5.779 (2.111)
25
−5.785 (−2.114)
−5.160 (−1.885)
8.201 (2.996)
−0.5319 (−0.3110)
3.177 (1.161)
5.778 (2.111)
50
−5.784 (−2.113)
−5.145 (−1.880)
8.179 (2.988)
−0.5318 (−0.1943)
3.177 (1.161)
5.778 (2.111)
100
−5.778 (−2.111)
−5.084 (−1.858)
8.094 (2.957)
−0.5314 (−0.1941)
3.177 (1.161)
5.773 (2.109)
250
−5.743 (−2.098)
−4.694 (−1.715)
7.551 (2.759)
−0.5286 (−0.1931)
3.178 (1.161)
5.744 (2.098)
500
−5.620 (−2.053)
−3.688 (−1.347)
6.116 (2.235)
−0.5189 (−0.1896)
3.182 (1.163)
5.644 (2.062)
1000
−5.192 (−1.897)
−2.005 (−0.7326)
3.490 (1.166)
−0.4811 (−0.1758)
3.182 (1.163)
5.298 (1.936)
2500
−3.608 (−1.318)
−0.9222 (−0.3369)
0.5051 (0.1845)
−0.2677 (−0.0978)
2.978 (1.088)
4.027 (1.471)
5000
−2.170 (−0.7929)
−1.038 (−0.3793)
−0.5971 (0.2182)
0.1189 (−0.0434)
2.238 (0.8176)
2.722 (0.9944)
10000
−1.289 (−0.471)
−0.9710 (−0.3548)
−0.8512 (0.3110)
0.4145 (−0.0151)
1.280 (0.4676)
1.551 (0.5666)
The corresponding refractivities Δn ×
108 are given in parentheses. These results are
graphically depicted in Fig. 7.
Table 5
Phase Shifts Δϕ (deg/m) and Associated
Refractivities Δn × 108 (in
Parentheses) for F′ = 3 →
F″ = 4 Hyperfine Transition Versus the
Amount off Line Center in Wave Numbers ka
F′ is the upper-state quantum number, whereas
F″ refers to the lower-state quantum
number.
Ref. 23.
Refs. 15 and 16. Values calculated by methods described in
text.
Table 2
Pressure-Broadening Coefficients
νPB (MHz/Torr)
for Various Buffer Gases
Stimulated-Emission Cross Section
σse in Units of
10−18 cm2 for each Atomic-Iodine Hyperfine
Transition as a Function of Total Pressure Broadening
Δν in Megahertza
Phase Shifts Δϕ (deg/m) per Meter Length for
Inversion Density of [NuT −
(NlT/2)] =
1016/cm3 as Function of Total Lorentz Broadening
in Megahertza
Δν
(MHz)
2–3
2–2
2–1
3–4
3–3
3–2
1
−5.785 (−2.114)
−5.166 (−1.887)
8.208 (2.999)
−0.5319 (−0.3110)
3.177 (1.161)
5.779 (2.111)
2.5
−5.785 (−2.114)
−5.166 (−1.887)
8.208 (2.999)
−0.5319 (−0.3110)
3.177 (1.161)
5.779 (2.111)
5
−5.785 (−2.114)
−5.165 (−1.887)
8.208 (2.999)
−0.5319 (−0.3110)
3.177 (1.161)
5.779 (2.111)
10
−5.785 (−2.114)
−5.165 (−1.887)
8.207 (2.999)
−0.5319 (−0.3110)
3.177 (1.161)
5.779 (2.111)
25
−5.785 (−2.114)
−5.160 (−1.885)
8.201 (2.996)
−0.5319 (−0.3110)
3.177 (1.161)
5.778 (2.111)
50
−5.784 (−2.113)
−5.145 (−1.880)
8.179 (2.988)
−0.5318 (−0.1943)
3.177 (1.161)
5.778 (2.111)
100
−5.778 (−2.111)
−5.084 (−1.858)
8.094 (2.957)
−0.5314 (−0.1941)
3.177 (1.161)
5.773 (2.109)
250
−5.743 (−2.098)
−4.694 (−1.715)
7.551 (2.759)
−0.5286 (−0.1931)
3.178 (1.161)
5.744 (2.098)
500
−5.620 (−2.053)
−3.688 (−1.347)
6.116 (2.235)
−0.5189 (−0.1896)
3.182 (1.163)
5.644 (2.062)
1000
−5.192 (−1.897)
−2.005 (−0.7326)
3.490 (1.166)
−0.4811 (−0.1758)
3.182 (1.163)
5.298 (1.936)
2500
−3.608 (−1.318)
−0.9222 (−0.3369)
0.5051 (0.1845)
−0.2677 (−0.0978)
2.978 (1.088)
4.027 (1.471)
5000
−2.170 (−0.7929)
−1.038 (−0.3793)
−0.5971 (0.2182)
0.1189 (−0.0434)
2.238 (0.8176)
2.722 (0.9944)
10000
−1.289 (−0.471)
−0.9710 (−0.3548)
−0.8512 (0.3110)
0.4145 (−0.0151)
1.280 (0.4676)
1.551 (0.5666)
The corresponding refractivities Δn ×
108 are given in parentheses. These results are
graphically depicted in Fig. 7.
Table 5
Phase Shifts Δϕ (deg/m) and Associated
Refractivities Δn × 108 (in
Parentheses) for F′ = 3 →
F″ = 4 Hyperfine Transition Versus the
Amount off Line Center in Wave Numbers ka